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Merge branch 'master' of https://github.com/eugenp/tutorials into task/BAEL-20665

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# Conflicts:
#	core-groovy-2/src/test/groovy/com/baeldung/metaprogramming/MetaprogrammingUnitTest.groovy
#	core-java-modules/pom.xml
#	pom.xml
This commit is contained in:
Dhawal Kapil
2020-01-12 20:55:19 +05:30
parent 73b5664785 6ff4e49984
commit 9b6b14a40b
296 changed files with 4437 additions and 457 deletions
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52
core-java-modules/core-java-14/pom.xml Normal file
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@@ -0,0 +1,52 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.baeldung</groupId>
<artifactId>core-java-14</artifactId>
<version>1.0.0-SNAPSHOT</version>
<name>core-java-14</name>
<packaging>jar</packaging>
<url>http://maven.apache.org</url>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
<relativePath>../../</relativePath>
</parent>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>${maven.compiler.source.version}</source>
<target>${maven.compiler.target.version}</target>
<compilerArgs>
<compilerArg>
--enable-preview
</compilerArg>
</compilerArgs>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>3.0.0-M3</version>
<configuration>
<argLine>--enable-preview</argLine>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<maven.compiler.source.version>14</maven.compiler.source.version>
<maven.compiler.target.version>14</maven.compiler.target.version>
</properties>
</project>

50
core-java-modules/core-java-14/src/main/java/com/baeldung/serial/MySerialClass.java Normal file
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@@ -0,0 +1,50 @@
package com.baeldung.serial;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamException;
import java.io.ObjectStreamField;
import java.io.Serial;
import java.io.Serializable;
/**
* Class showcasing the usage of the Java 14 @Serial annotation.
*
* @author Donato Rimenti
*/
public class MySerialClass implements Serializable {
@Serial
private static final ObjectStreamField[] serialPersistentFields = null;
@Serial
private static final long serialVersionUID = 1;
@Serial
private void writeObject(ObjectOutputStream stream) throws IOException {
// ...
}
@Serial
private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
// ...
}
@Serial
private void readObjectNoData() throws ObjectStreamException {
// ...
}
@Serial
private Object writeReplace() throws ObjectStreamException {
// ...
return null;
}
@Serial
private Object readResolve() throws ObjectStreamException {
// ...
return null;
}
}

35
core-java-modules/core-java-arrays-2/pom.xml
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@@ -19,6 +19,16 @@
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>${commons-lang3.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-core</artifactId>
<version>${jmh.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-generator-annprocess</artifactId>
<version>${jmh.version}</version>
</dependency>
<!-- test scoped -->
<dependency>
@@ -37,9 +47,34 @@
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<finalName>benchmarks</finalName>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>org.openjdk.jmh.Main</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<properties>
<jmh.version>1.19</jmh.version>
<!-- util -->
<commons-lang3.version>3.9</commons-lang3.version>
<!-- testing -->

72
core-java-modules/core-java-arrays-2/src/main/java/com/baeldung/arraysort/ArraySortingBenchmark.java Normal file
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@@ -0,0 +1,72 @@
package com.baeldung.arraysort;
import java.util.Arrays;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;
@BenchmarkMode(Mode.AverageTime)
@Warmup(iterations = 5)
@Measurement(iterations = 10)
@Fork(2)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
public class ArraySortingBenchmark {
@State(Scope.Benchmark)
public static class ArrayContainer {
@Param({ "1000", "10000", "100000", "1000000" })
int arraySize;
// initial unsorted array
int[] unsortedArray;
//cloned array to sort
int[] arrayToSort;
@Setup(Level.Trial)
public void createUnSortedArray() {
unsortedArray = new int[arraySize];
for (int i = 0; i < arraySize; i++) {
unsortedArray[i] = new Random().nextInt(1000);
}
}
@Setup(Level.Invocation)
public void createUnSortedArrayCopy() {
arrayToSort = unsortedArray.clone();
}
int[] getArrayToSort() {
return arrayToSort;
}
}
@Benchmark
public void benchmark_arrays_parallel_sort(ArrayContainer d, Blackhole b) {
int[] arr = d.getArrayToSort();
Arrays.parallelSort(arr);
b.consume(arr);
}
@Benchmark
public void benchmark_arrays_sort(ArrayContainer d, Blackhole b) {
int[] arr = d.getArrayToSort();
Arrays.sort(arr);
b.consume(arr);
}
}

18
core-java-modules/core-java-collections-list-3/src/main/java/com/baeldung/list/duplicatescounter/DuplicatesCounter.java
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@@ -24,11 +24,21 @@ public class DuplicatesCounter {
return resultMap;
}
public static <T> Map<T, Long> countByClassicalLoopWithMapCompute(List<T> inputList) {
public static <T> Map<T, Long> countByForEachLoopWithGetOrDefault(List<T> inputList) {
Map<T, Long> resultMap = new HashMap<>();
for (T element : inputList) {
resultMap.compute(element, (k, v) -> v == null ? 1 : v + 1);
}
inputList.forEach(e -> resultMap.put(e, resultMap.getOrDefault(e, 0L) + 1L));
return resultMap;
}
public static <T> Map<T, Long> countByForEachLoopWithMapCompute(List<T> inputList) {
Map<T, Long> resultMap = new HashMap<>();
inputList.forEach(e -> resultMap.compute(e, (k, v) -> v == null ? 1L : v + 1L));
return resultMap;
}
public static <T> Map<T, Long> countByForEachLoopWithMapMerge(List<T> inputList) {
Map<T, Long> resultMap = new HashMap<>();
inputList.forEach(e -> resultMap.merge(e, 1L, Long::sum));
return resultMap;
}

16
core-java-modules/core-java-collections-list-3/src/test/java/com/baeldung/list/duplicatescounter/DuplicatesCounterUnitTest.java
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@@ -11,7 +11,6 @@ import static org.assertj.core.data.MapEntry.entry;
class DuplicatesCounterUnitTest {
private static List<String> INPUT_LIST = Lists.list(
"expect1",
"expect2", "expect2",
@@ -24,10 +23,21 @@ class DuplicatesCounterUnitTest {
verifyResult(result);
}
@Test
void givenInput_whenCountByForEachLoopWithGetOrDefault_thenGetResultMap() {
Map<String, Long> result = DuplicatesCounter.countByForEachLoopWithGetOrDefault(INPUT_LIST);
verifyResult(result);
}
@Test
void givenInput_whenCountByClassicalLoopWithMapCompute_thenGetResultMap() {
Map<String, Long> result = DuplicatesCounter.countByClassicalLoopWithMapCompute(INPUT_LIST);
void givenInput_whenCountByForEachLoopWithMapCompute_thenGetResultMap() {
Map<String, Long> result = DuplicatesCounter.countByForEachLoopWithMapCompute(INPUT_LIST);
verifyResult(result);
}
@Test
void givenInput_whenCountByForEachLoopWithMapMerge_thenGetResultMap() {
Map<String, Long> result = DuplicatesCounter.countByForEachLoopWithMapMerge(INPUT_LIST);
verifyResult(result);
}

63
core-java-modules/core-java-concurrency-advanced-3/pom.xml
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@@ -23,6 +23,37 @@
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.jcabi</groupId>
<artifactId>jcabi-aspects</artifactId>
<version>${jcabi-aspects.version}</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${aspectjrt.version}</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>${guava.version}</version>
</dependency>
<dependency>
<groupId>org.cactoos</groupId>
<artifactId>cactoos</artifactId>
<version>${cactoos.version}</version>
</dependency>
<dependency>
<groupId>com.ea.async</groupId>
<artifactId>ea-async</artifactId>
<version>${ea-async.version}</version>
</dependency>
</dependencies>
<build>
@@ -36,6 +67,30 @@
<target>${maven.compiler.target}</target>
</configuration>
</plugin>
<plugin>
<groupId>com.jcabi</groupId>
<artifactId>jcabi-maven-plugin</artifactId>
<version>${jcabi-maven-plugin.version}</version>
<executions>
<execution>
<goals>
<goal>ajc</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjtools</artifactId>
<version>${aspectjtools.version}</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>${aspectjweaver.version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
<resources>
<resource>
@@ -49,6 +104,14 @@
<assertj.version>3.14.0</assertj.version>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<jcabi-aspects.version>0.22.6</jcabi-aspects.version>
<aspectjrt.version>1.9.5</aspectjrt.version>
<guava.version>28.2-jre</guava.version>
<cactoos.version>0.43</cactoos.version>
<ea-async.version>1.2.3</ea-async.version>
<jcabi-maven-plugin.version>0.14.1</jcabi-maven-plugin.version>
<aspectjtools.version>1.9.1</aspectjtools.version>
<aspectjweaver.version>1.9.1</aspectjweaver.version>
</properties>
</project>

57
core-java-modules/core-java-concurrency-advanced-3/src/main/java/com/baeldung/async/EAAsyncExample.java Normal file
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@@ -0,0 +1,57 @@
package com.baeldung.async;
import static com.ea.async.Async.await;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import com.ea.async.Async;
public class EAAsyncExample {
static {
Async.init();
}
public static void main(String[] args) throws Exception {
usingCompletableFuture();
usingAsyncAwait();
}
public static void usingCompletableFuture() throws InterruptedException, ExecutionException, Exception {
CompletableFuture<Void> completableFuture = hello()
.thenComposeAsync(hello -> mergeWorld(hello))
.thenAcceptAsync(helloWorld -> print(helloWorld))
.exceptionally( throwable -> {
System.out.println(throwable.getCause());
return null;
});
completableFuture.get();
}
public static CompletableFuture<String> hello() {
CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello");
return completableFuture;
}
public static CompletableFuture<String> mergeWorld(String s) {
CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> {
return s + " World!";
});
return completableFuture;
}
public static void print(String str) {
CompletableFuture.runAsync(() -> System.out.println(str));
}
private static void usingAsyncAwait() {
try {
String hello = await(hello());
String helloWorld = await(mergeWorld(hello));
await(CompletableFuture.runAsync(() -> print(helloWorld)));
} catch (Exception e) {
e.printStackTrace();
}
}
}

183
core-java-modules/core-java-concurrency-advanced-3/src/main/java/com/baeldung/async/JavaAsync.java Normal file
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@@ -0,0 +1,183 @@
package com.baeldung.async;
import static com.ea.async.Async.await;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import com.google.common.util.concurrent.AsyncCallable;
import com.google.common.util.concurrent.Callables;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.common.util.concurrent.MoreExecutors;
import com.jcabi.aspects.Async;
import com.jcabi.aspects.Loggable;
public class JavaAsync {
static {
com.ea.async.Async.init();
}
private static final ExecutorService threadpool = Executors.newCachedThreadPool();
public static void main (String[] args) throws InterruptedException, ExecutionException {
int number = 20;
//Thread Example
factorialUsingThread(number).start();
//FutureTask Example
Future<Long> futureTask = factorialUsingFutureTask(number);
System.out.println("Factorial of " + number + " is: " + futureTask.get());
// CompletableFuture Example
Future<Long> completableFuture = factorialUsingCompletableFuture(number);
System.out.println("Factorial of " + number + " is: " + completableFuture.get());
// EA Async example
System.out.println("Factorial of " + number + " is: " + factorialUsingEAAsync(number));
// cactoos async example
Future<Long> asyncFuture = factorialUsingCactoos(number);
System.out.println("Factorial of " + number + " is: " + asyncFuture.get());
// Guava example
ListenableFuture<Long> guavaFuture = factorialUsingGuavaServiceSubmit(number);
System.out.println("Factorial of " + number + " is: " + guavaFuture.get());
ListenableFuture<Long> guavaFutures = factorialUsingGuavaFutures(number);
System.out.println("Factorial of " + number + " is: " + guavaFutures.get());
// @async jcabi-aspect example
Future<Long> aspectFuture = factorialUsingJcabiAspect(number);
System.out.println("Factorial of " + number + " is: " + aspectFuture.get());
}
/**
* Finds factorial of a number
* @param number
* @return
*/
public static long factorial(int number) {
long result = 1;
for(int i=number;i>0;i--) {
result *= i;
}
return result;
}
/**
* Finds factorial of a number using Thread
* @param number
* @return
*/
@Loggable
public static Thread factorialUsingThread(int number) {
Thread newThread = new Thread(() -> {
System.out.println("Factorial of " + number + " is: " + factorial(number));
});
return newThread;
}
/**
* Finds factorial of a number using FutureTask
* @param number
* @return
*/
@Loggable
public static Future<Long> factorialUsingFutureTask(int number) {
Future<Long> futureTask = threadpool.submit(() -> factorial(number));
while (!futureTask.isDone()) {
System.out.println("FutureTask is not finished yet...");
}
return futureTask;
}
/**
* Finds factorial of a number using CompletableFuture
* @param number
* @return
*/
@Loggable
public static Future<Long> factorialUsingCompletableFuture(int number) {
CompletableFuture<Long> completableFuture = CompletableFuture.supplyAsync(() -> factorial(number));
return completableFuture;
}
/**
* Finds factorial of a number using EA Async
* @param number
* @return
*/
@Loggable
public static long factorialUsingEAAsync(int number) {
CompletableFuture<Long> completableFuture = CompletableFuture.supplyAsync(() -> factorial(number));
long result = await(completableFuture);
return result;
}
/**
* Finds factorial of a number using Async of Cactoos
* @param number
* @return
* @throws InterruptedException
* @throws ExecutionException
*/
@Loggable
public static Future<Long> factorialUsingCactoos(int number) throws InterruptedException, ExecutionException {
org.cactoos.func.Async<Integer, Long> asyncFunction = new org.cactoos.func.Async<Integer, Long>(input -> factorial(input));
Future<Long> asyncFuture = asyncFunction.apply(number);
return asyncFuture;
}
/**
* Finds factorial of a number using Guava's ListeningExecutorService.submit()
* @param number
* @return
*/
@Loggable
public static ListenableFuture<Long> factorialUsingGuavaServiceSubmit(int number) {
ListeningExecutorService service = MoreExecutors.listeningDecorator(threadpool);
ListenableFuture<Long> factorialFuture = (ListenableFuture<Long>) service.submit(()-> factorial(number));
return factorialFuture;
}
/**
* Finds factorial of a number using Guava's Futures.submitAsync()
* @param number
* @return
*/
@Loggable
public static ListenableFuture<Long> factorialUsingGuavaFutures(int number) {
ListeningExecutorService service = MoreExecutors.listeningDecorator(threadpool);
AsyncCallable<Long> asyncCallable = Callables.asAsyncCallable(new Callable<Long>() {
public Long call() {
return factorial(number);
}
}, service);
return Futures.submitAsync(asyncCallable, service);
}
/**
* Finds factorial of a number using @Async of jcabi-aspects
* @param number
* @return
*/
@Async
@Loggable
public static Future<Long> factorialUsingJcabiAspect(int number) {
Future<Long> factorialFuture = CompletableFuture.supplyAsync(() -> factorial(number));
return factorialFuture;
}
}

6
core-java-modules/core-java-datetime-computations/README.md → core-java-modules/core-java-date-operations-1/README.md
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@@ -1,6 +1,5 @@
## Java Date/time computations Cookbooks and Examples
This module contains articles about date and time computations in Java.
## Core Date Operations (Part 1)
This module contains articles about date operations in Java.
### Relevant Articles:
- [Difference Between Two Dates in Java](http://www.baeldung.com/java-date-difference)
@@ -13,3 +12,4 @@ This module contains articles about date and time computations in Java.
- [Increment Date in Java](http://www.baeldung.com/java-increment-date)
- [Add Hours To a Date In Java](http://www.baeldung.com/java-add-hours-date)
- [Introduction to Joda-Time](http://www.baeldung.com/joda-time)
- [[Next -->]](/core-java-modules/core-java-date-operations-2)

6
core-java-modules/core-java-datetime-computations/pom.xml → core-java-modules/core-java-date-operations-1/pom.xml
View File

@@ -2,9 +2,9 @@
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>core-java-datetime-computations</artifactId>
<artifactId>core-java-date-operations-1</artifactId>
<version>${project.parent.version}</version>
<name>core-java-datetime-computations</name>
<name>core-java-date-operations-1</name>
<packaging>jar</packaging>
<parent>
@@ -41,7 +41,7 @@
</dependencies>
<build>
<finalName>core-java-datetime-computations</finalName>
<finalName>core-java-date-operations-1</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>

0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/date/AgeCalculator.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/date/AgeCalculator.java
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0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/date/DateWithoutTime.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/date/DateWithoutTime.java
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0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/datetime/AddHoursToDate.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/datetime/AddHoursToDate.java
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0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/datetime/DateExtractYearMonthDayIntegerValues.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/datetime/DateExtractYearMonthDayIntegerValues.java
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0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/datetime/LocalDateExtractYearMonthDayIntegerValues.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/datetime/LocalDateExtractYearMonthDayIntegerValues.java
View File

0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/datetime/LocalDateTimeExtractYearMonthDayIntegerValues.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/datetime/LocalDateTimeExtractYearMonthDayIntegerValues.java
View File

0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/datetime/OffsetDateTimeExtractYearMonthDayIntegerValues.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/datetime/OffsetDateTimeExtractYearMonthDayIntegerValues.java
View File

0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/datetime/ZonedDateTimeExtractYearMonthDayIntegerValues.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/datetime/ZonedDateTimeExtractYearMonthDayIntegerValues.java
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0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/datetime/modify/DateIncrementer.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/datetime/modify/DateIncrementer.java
View File

0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/gregorian/calendar/GregorianCalendarExample.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/gregorian/calendar/GregorianCalendarExample.java
View File

0
core-java-modules/core-java-datetime-computations/src/main/java/com/baeldung/java9/time/TimeApi.java → core-java-modules/core-java-date-operations-1/src/main/java/com/baeldung/java9/time/TimeApi.java
View File

0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/date/AgeCalculatorUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/date/AgeCalculatorUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/date/DateDiffUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/date/DateDiffUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/date/DateWithoutTimeUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/date/DateWithoutTimeUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/datetime/AddHoursToDateUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/datetime/AddHoursToDateUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/datetime/DateExtractYearMonthDayIntegerValuesUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/datetime/DateExtractYearMonthDayIntegerValuesUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/datetime/LocalDateExtractYearMonthDayIntegerValuesUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/datetime/LocalDateExtractYearMonthDayIntegerValuesUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/datetime/LocalDateTimeExtractYearMonthDayIntegerValuesUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/datetime/LocalDateTimeExtractYearMonthDayIntegerValuesUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/datetime/OffsetDateTimeExtractYearMonthDayIntegerValuesUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/datetime/OffsetDateTimeExtractYearMonthDayIntegerValuesUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/datetime/ZonedDateTimeExtractYearMonthDayIntegerValuesUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/datetime/ZonedDateTimeExtractYearMonthDayIntegerValuesUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/datetime/modify/DateIncrementerUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/datetime/modify/DateIncrementerUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/dst/DaylightSavingTimeExamplesUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/dst/DaylightSavingTimeExamplesUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/dst/DaylightSavingTimeJavaTimeExamplesUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/dst/DaylightSavingTimeJavaTimeExamplesUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/gregorian/calendar/GregorianCalendarTester.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/gregorian/calendar/GregorianCalendarTester.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/java9/time/TimeApiUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/java9/time/TimeApiUnitTest.java
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0
core-java-modules/core-java-datetime-computations/src/test/java/com/baeldung/jodatime/JodaTimeUnitTest.java → core-java-modules/core-java-date-operations-1/src/test/java/com/baeldung/jodatime/JodaTimeUnitTest.java
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3
core-java-modules/core-java-date-operations/README.md → core-java-modules/core-java-date-operations-2/README.md
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@@ -1,4 +1,4 @@
## Core Date Operations
## Core Date Operations (Part 2)
This module contains articles about date operations in Java.
### Relevant Articles:
@@ -6,3 +6,4 @@ This module contains articles about date operations in Java.
- [Skipping Weekends While Adding Days to LocalDate in Java 8](https://www.baeldung.com/java-localdate-add-days-skip-weekends)
- [Checking If Two Java Dates Are on the Same Day](https://www.baeldung.com/java-check-two-dates-on-same-day)
- [Converting Java Date to OffsetDateTime](https://www.baeldung.com/java-convert-date-to-offsetdatetime)
- [[<-- Prev]](/core-java-modules/core-java-date-operations-1)

11
core-java-modules/core-java-date-operations/pom.xml → core-java-modules/core-java-date-operations-2/pom.xml
View File

@@ -3,9 +3,9 @@
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>core-java-date-operations</artifactId>
<artifactId>core-java-date-operations-2</artifactId>
<version>${project.parent.version}</version>
<name>core-java-date-operations</name>
<name>core-java-date-operations-2</name>
<packaging>jar</packaging>
<parent>
@@ -31,11 +31,18 @@
<artifactId>hirondelle-date4j</artifactId>
<version>${hirondelle-date4j.version}</version>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<properties>
<joda-time.version>2.10</joda-time.version>
<hirondelle-date4j.version>1.5.1</hirondelle-date4j.version>
<assertj.version>3.14.0</assertj.version>
</properties>
</project>

120
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/date/comparison/DateComparisonUtils.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/date/comparison/DateComparisonUtils.java
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@@ -1,55 +1,65 @@
package com.baeldung.date.comparison;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.ZoneId;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import org.apache.commons.lang3.time.DateUtils;
import hirondelle.date4j.DateTime;
public class DateComparisonUtils {
public static boolean isSameDayUsingLocalDate(Date date1, Date date2) {
LocalDate localDate1 = date1.toInstant()
.atZone(ZoneId.systemDefault())
.toLocalDate();
LocalDate localDate2 = date2.toInstant()
.atZone(ZoneId.systemDefault())
.toLocalDate();
return localDate1.isEqual(localDate2);
}
public static boolean isSameDayUsingSimpleDateFormat(Date date1, Date date2) {
SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
return fmt.format(date1)
.equals(fmt.format(date2));
}
public static boolean isSameDayUsingCalendar(Date date1, Date date2) {
Calendar calendar1 = Calendar.getInstance();
calendar1.setTime(date1);
Calendar calendar2 = Calendar.getInstance();
calendar2.setTime(date2);
return calendar1.get(Calendar.YEAR) == calendar2.get(Calendar.YEAR) && calendar1.get(Calendar.MONTH) == calendar2.get(Calendar.MONTH) && calendar1.get(Calendar.DAY_OF_MONTH) == calendar2.get(Calendar.DAY_OF_MONTH);
}
public static boolean isSameDayUsingApacheCommons(Date date1, Date date2) {
return DateUtils.isSameDay(date1, date2);
}
public static boolean isSameDayUsingJoda(Date date1, Date date2) {
org.joda.time.LocalDate localDate1 = new org.joda.time.LocalDate(date1);
org.joda.time.LocalDate localDate2 = new org.joda.time.LocalDate(date2);
return localDate1.equals(localDate2);
}
public static boolean isSameDayUsingDate4j(Date date1, Date date2) {
DateTime dateObject1 = DateTime.forInstant(date1.getTime(), TimeZone.getDefault());
DateTime dateObject2 = DateTime.forInstant(date2.getTime(), TimeZone.getDefault());
return dateObject1.isSameDayAs(dateObject2);
}
}
package com.baeldung.date.comparison;
import java.text.SimpleDateFormat;
import java.time.Instant;
import java.time.LocalDate;
import java.time.ZoneId;
import java.time.temporal.ChronoUnit;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import org.apache.commons.lang3.time.DateUtils;
import hirondelle.date4j.DateTime;
public class DateComparisonUtils {
public static boolean isSameDayUsingLocalDate(Date date1, Date date2) {
LocalDate localDate1 = date1.toInstant()
.atZone(ZoneId.systemDefault())
.toLocalDate();
LocalDate localDate2 = date2.toInstant()
.atZone(ZoneId.systemDefault())
.toLocalDate();
return localDate1.isEqual(localDate2);
}
public static boolean isSameDayUsingInstant(Date date1, Date date2) {
Instant instant1 = date1.toInstant()
.truncatedTo(ChronoUnit.DAYS);
Instant instant2 = date2.toInstant()
.truncatedTo(ChronoUnit.DAYS);
return instant1.equals(instant2);
}
public static boolean isSameDayUsingSimpleDateFormat(Date date1, Date date2) {
SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
return fmt.format(date1)
.equals(fmt.format(date2));
}
public static boolean isSameDayUsingCalendar(Date date1, Date date2) {
Calendar calendar1 = Calendar.getInstance();
calendar1.setTime(date1);
Calendar calendar2 = Calendar.getInstance();
calendar2.setTime(date2);
return calendar1.get(Calendar.YEAR) == calendar2.get(Calendar.YEAR) && calendar1.get(Calendar.MONTH) == calendar2.get(Calendar.MONTH) && calendar1.get(Calendar.DAY_OF_MONTH) == calendar2.get(Calendar.DAY_OF_MONTH);
}
public static boolean isSameDayUsingApacheCommons(Date date1, Date date2) {
return DateUtils.isSameDay(date1, date2);
}
public static boolean isSameDayUsingJoda(Date date1, Date date2) {
org.joda.time.LocalDate localDate1 = new org.joda.time.LocalDate(date1);
org.joda.time.LocalDate localDate2 = new org.joda.time.LocalDate(date2);
return localDate1.equals(localDate2);
}
public static boolean isSameDayUsingDate4j(Date date1, Date date2) {
DateTime dateObject1 = DateTime.forInstant(date1.getTime(), TimeZone.getDefault());
DateTime dateObject2 = DateTime.forInstant(date2.getTime(), TimeZone.getDefault());
return dateObject1.isSameDayAs(dateObject2);
}
}

0
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/datetime/CalendarUtils.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/datetime/CalendarUtils.java
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0
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/datetime/DateUtils.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/datetime/DateUtils.java
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0
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/datetime/sql/DateUtils.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/datetime/sql/DateUtils.java
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0
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/datetime/sql/TimeUtils.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/datetime/sql/TimeUtils.java
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0
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/datetime/sql/TimestampUtils.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/datetime/sql/TimestampUtils.java
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0
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/offsetdatetime/ConvertToOffsetDateTime.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/offsetdatetime/ConvertToOffsetDateTime.java
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0
core-java-modules/core-java-date-operations/src/main/java/com/baeldung/skipweekends/AddSubtractDaysSkippingWeekendsUtils.java → core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/skipweekends/AddSubtractDaysSkippingWeekendsUtils.java
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19
core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/timer/DatabaseMigrationTask.java Normal file
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@@ -0,0 +1,19 @@
package com.baeldung.timer;
import java.util.List;
import java.util.TimerTask;
public class DatabaseMigrationTask extends TimerTask {
private List<String> oldDatabase;
private List<String> newDatabase;
public DatabaseMigrationTask(List<String> oldDatabase, List<String> newDatabase) {
this.oldDatabase = oldDatabase;
this.newDatabase = newDatabase;
}
@Override
public void run() {
newDatabase.addAll(oldDatabase);
}
}

14
core-java-modules/core-java-date-operations-2/src/main/java/com/baeldung/timer/NewsletterTask.java Normal file
View File

@@ -0,0 +1,14 @@
package com.baeldung.timer;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.TimerTask;
public class NewsletterTask extends TimerTask {
@Override
public void run() {
System.out.println("Email sent at: "
+ LocalDateTime.ofInstant(Instant.ofEpochMilli(scheduledExecutionTime()), ZoneId.systemDefault()));
}
}

110
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/date/comparison/DateComparisonUtilsUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/date/comparison/DateComparisonUtilsUnitTest.java
View File

@@ -1,53 +1,57 @@
package com.baeldung.date.comparison;
import org.junit.Test;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Date;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class DateComparisonUtilsUnitTest {
private Date day1Morning = toDate(LocalDateTime.of(2019, 10, 19, 6, 30, 40));
private Date day1Evening = toDate(LocalDateTime.of(2019, 10, 19, 18, 30, 50));
private Date day2Morning = toDate(LocalDateTime.of(2019, 10, 20, 6, 30, 50));
private Date toDate(LocalDateTime localDateTime) {
return Date.from(localDateTime.atZone(ZoneId.systemDefault())
.toInstant());
}
@Test
public void givenDatesWithDifferentTime_whenIsSameDay_thenReturnsTrue() {
assertTrue(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day1Evening));
}
@Test
public void givenDates_whenIsDifferentDay_thenReturnsFalse() {
assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Evening, day2Morning));
}
}
package com.baeldung.date.comparison;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Date;
import org.junit.Test;
public class DateComparisonUtilsUnitTest {
private Date day1Morning = toDate(LocalDateTime.of(2019, 10, 19, 6, 30, 40));
private Date day1Evening = toDate(LocalDateTime.of(2019, 10, 19, 18, 30, 50));
private Date day2Morning = toDate(LocalDateTime.of(2019, 10, 20, 6, 30, 50));
private Date toDate(LocalDateTime localDateTime) {
return Date.from(localDateTime.atZone(ZoneId.systemDefault())
.toInstant());
}
@Test
public void givenDatesWithDifferentTime_whenIsSameDay_thenReturnsTrue() {
assertTrue(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingInstant(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day1Evening));
assertTrue(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day1Evening));
}
@Test
public void givenDates_whenIsDifferentDay_thenReturnsFalse() {
assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingLocalDate(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingInstant(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingInstant(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingSimpleDateFormat(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingCalendar(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingApacheCommons(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingJoda(day1Evening, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Morning, day2Morning));
assertFalse(DateComparisonUtils.isSameDayUsingDate4j(day1Evening, day2Morning));
}
}

0
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/datetime/CalendarUtilsUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/CalendarUtilsUnitTest.java
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6
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/datetime/DateUtilsUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/DateUtilsUnitTest.java
View File

@@ -9,12 +9,6 @@ import static org.junit.Assert.assertEquals;
public class DateUtilsUnitTest {
@Test
public void givenTimeMillis_thenDateIsReturned() {
Date now = DateUtils.getNow();
assertEquals(DateUtils.getDate(now.getTime()), now);
}
@Test
public void givenDateAndPattern_thenDateIsCorrectlyReturned() throws ParseException {
long milliseconds = new Date(2020 - 1900, 0, 1).getTime();

5
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/datetime/sql/DateUtilsUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/sql/DateUtilsUnitTest.java
View File

@@ -9,11 +9,6 @@ import org.junit.Test;
public class DateUtilsUnitTest {
@Test
public void givenCurrentDate_thenTodayIsReturned() {
assertEquals(DateUtils.getNow().toLocalDate(), LocalDate.now());
}
@Test(expected = IllegalArgumentException.class)
public void givenDateAsString_whenPatternIsNotRespected_thenExceptionIsThrown() {
DateUtils.getDate("2020 01 01");

0
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/datetime/sql/TimeUtilsUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/sql/TimeUtilsUnitTest.java
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13
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/datetime/sql/TimestampUtilsUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/datetime/sql/TimestampUtilsUnitTest.java
View File

@@ -1,22 +1,13 @@
package com.baeldung.datetime.sql;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
import com.baeldung.datetime.sql.TimestampUtils;
import java.text.ParseException;
import java.util.Date;
import static org.junit.Assert.assertEquals;
public class TimestampUtilsUnitTest {
@Test
public void givenCurrentTimestamp_thenNowIsReturned() {
assertEquals(TimestampUtils.getNow()
.getTime(), new Date().getTime());
}
@Test(expected = IllegalArgumentException.class)
public void givenTimestampAsString_whenPatternIsNotRespected_thenExceptionIsThrown() {
TimestampUtils.getTimestamp("2020/01/01 10:11-12");

0
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/jvmtimezone/ModifyDefaultTimezoneUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/jvmtimezone/ModifyDefaultTimezoneUnitTest.java
View File

0
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/jvmtimezone/ModifyTimezonePropertyUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/jvmtimezone/ModifyTimezonePropertyUnitTest.java
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0
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/offsetdatetime/ConvertToOffsetDateTimeUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/offsetdatetime/ConvertToOffsetDateTimeUnitTest.java
View File

0
core-java-modules/core-java-date-operations/src/test/java/com/baeldung/skipweekends/AddSubtractDaysSkippingWeekendsUtilsUnitTest.java → core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/skipweekends/AddSubtractDaysSkippingWeekendsUtilsUnitTest.java
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44
core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/timer/DatabaseMigrationTaskUnitTest.java Normal file
View File

@@ -0,0 +1,44 @@
package com.baeldung.timer;
import org.junit.jupiter.api.Test;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.*;
import static org.assertj.core.api.Assertions.assertThat;
class DatabaseMigrationTaskUnitTest {
@Test
void givenDatabaseMigrationTask_whenTimerScheduledForNowPlusTwoSeconds_thenDataMigratedAfterTwoSeconds() throws Exception {
List<String> oldDatabase = Arrays.asList("Harrison Ford", "Carrie Fisher", "Mark Hamill");
List<String> newDatabase = new ArrayList<>();
LocalDateTime twoSecondsLater = LocalDateTime.now().plusSeconds(2);
Date twoSecondsLaterAsDate = Date.from(twoSecondsLater.atZone(ZoneId.systemDefault()).toInstant());
new Timer().schedule(new DatabaseMigrationTask(oldDatabase, newDatabase), twoSecondsLaterAsDate);
while (LocalDateTime.now().isBefore(twoSecondsLater)) {
assertThat(newDatabase).isEmpty();
Thread.sleep(500);
}
assertThat(newDatabase).containsExactlyElementsOf(oldDatabase);
}
@Test
void givenDatabaseMigrationTask_whenTimerScheduledInTwoSeconds_thenDataMigratedAfterTwoSeconds() throws Exception {
List<String> oldDatabase = Arrays.asList("Harrison Ford", "Carrie Fisher", "Mark Hamill");
List<String> newDatabase = new ArrayList<>();
new Timer().schedule(new DatabaseMigrationTask(oldDatabase, newDatabase), 2000);
LocalDateTime twoSecondsLater = LocalDateTime.now().plusSeconds(2);
while (LocalDateTime.now().isBefore(twoSecondsLater)) {
assertThat(newDatabase).isEmpty();
Thread.sleep(500);
}
assertThat(newDatabase).containsExactlyElementsOf(oldDatabase);
}
}

33
core-java-modules/core-java-date-operations-2/src/test/java/com/baeldung/timer/NewsletterTaskUnitTest.java Normal file
View File

@@ -0,0 +1,33 @@
package com.baeldung.timer;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Test;
import java.util.Timer;
class NewsletterTaskUnitTest {
private final Timer timer = new Timer();
@AfterEach
void afterEach() {
timer.cancel();
}
@Test
void givenNewsletterTask_whenTimerScheduledEachSecondFixedDelay_thenNewsletterSentEachSecond() throws Exception {
timer.schedule(new NewsletterTask(), 0, 1000);
for (int i = 0; i < 3; i++) {
Thread.sleep(1000);
}
}
@Test
void givenNewsletterTask_whenTimerScheduledEachSecondFixedRate_thenNewsletterSentEachSecond() throws Exception {
timer.scheduleAtFixedRate(new NewsletterTask(), 0, 1000);
for (int i = 0; i < 3; i++) {
Thread.sleep(1000);
}
}
}

45
core-java-modules/core-java-datetime-java8/src/main/java/com/baeldung/datebasics/CreateDate.java Normal file
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package com.baeldung.datebasics;
import java.time.Clock;
import java.time.LocalDate;
import java.time.Month;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
public class CreateDate {
public LocalDate getTodaysDate() {
return LocalDate.now();
}
public LocalDate getTodaysDateFromClock() {
return LocalDate.now(Clock.systemDefaultZone());
}
public LocalDate getTodaysDateFromZone(String zone) {
return LocalDate.now(ZoneId.of(zone));
}
public LocalDate getCustomDateOne(int year, int month, int dayOfMonth) {
return LocalDate.of(year, month, dayOfMonth);
}
public LocalDate getCustomDateTwo(int year, Month month, int dayOfMonth) {
return LocalDate.of(year, month, dayOfMonth);
}
public LocalDate getDateFromEpochDay(long epochDay) {
return LocalDate.ofEpochDay(epochDay);
}
public LocalDate getDateFromYearAndDayOfYear(int year, int dayOfYear) {
return LocalDate.ofYearDay(year, dayOfYear);
}
public LocalDate getDateFromString(String date) {
return LocalDate.parse(date);
}
public LocalDate getDateFromStringAndFormatter(String date, String pattern) {
return LocalDate.parse(date, DateTimeFormatter.ofPattern(pattern));
}
}

56
core-java-modules/core-java-datetime-java8/src/test/java/com/baeldung/datebasics/CreateDateUnitTest.java Normal file
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package com.baeldung.datebasics;
import static org.junit.Assert.assertEquals;
import java.time.Month;
import org.junit.Test;
public class CreateDateUnitTest {
private CreateDate date = new CreateDate();
@Test
public void whenUsingNowMethod_thenLocalDate() {
assertEquals("2020-01-08", date.getTodaysDate());
}
@Test
public void whenUsingClock_thenLocalDate() {
assertEquals("2020-01-08", date.getTodaysDateFromClock());
}
@Test
public void givenValues_whenUsingZone_thenLocalDate() {
assertEquals("2020-01-08", date.getTodaysDateFromZone("Asia/Kolkata"));
}
@Test
public void givenValues_whenUsingOfMethod_thenLocalDate() {
assertEquals("2020-01-08", date.getCustomDateOne(2020, 1, 8));
}
@Test
public void givenValuesWithMonthEnum_whenUsingOfMethod_thenLocalDate() {
assertEquals("2020-01-08", date.getCustomDateTwo(2020, Month.JANUARY, 8));
}
@Test
public void givenValues_whenUsingEpochDay_thenLocalDate() {
assertEquals("2020-01-08", date.getDateFromEpochDay(18269));
}
@Test
public void givenValues_whenUsingYearDay_thenLocalDate() {
assertEquals("2020-01-08", date.getDateFromYearAndDayOfYear(2020, 8));
}
@Test
public void givenValues_whenUsingParse_thenLocalDate() {
assertEquals("2020-01-08", date.getDateFromString("2020-01-08"));
}
@Test
public void givenValuesWithFormatter_whenUsingParse_thenLocalDate() {
assertEquals("2020-01-08", date.getDateFromStringAndFormatter("8-Jan-2020", "d-MMM-yyyy"));
}
}

14
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/FinallyExample.java Normal file
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package com.baeldung.finallykeyword;
public class FinallyExample {
public void printCount(String count) {
try {
System.out.println("The count is " + Integer.parseInt(count));
} catch (NumberFormatException e) {
System.out.println("No count");
} finally {
System.out.println("In finally");
}
}
}

53
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/FinallyExecutedCases.java Normal file
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package com.baeldung.finallykeyword;
public class FinallyExecutedCases {
public void noExceptionFinally() {
try {
System.out.println("Inside try");
} finally {
System.out.println("Inside finally");
}
}
public void unhandledException() throws Exception {
try {
System.out.println("Inside try");
throw new Exception();
} finally {
System.out.println("Inside finally");
}
}
public void handledException() {
try {
System.out.println("Inside try");
throw new Exception();
} catch (Exception e) {
System.out.println("Inside catch");
} finally {
System.out.println("Inside finally");
}
}
public String returnFromTry() {
try {
System.out.println("Inside try");
return "from try";
} finally {
System.out.println("Inside finally");
}
}
public String returnFromCatch() {
try {
System.out.println("Inside try");
throw new Exception();
} catch (Exception e) {
System.out.println("Inside catch");
return "from catch";
} finally {
System.out.println("Inside finally");
}
}
}

54
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/FinallyNotExecutedCases.java Normal file
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package com.baeldung.finallykeyword;
public class FinallyNotExecutedCases {
public void callingSystemExit() {
try {
System.out.println("Inside try");
System.exit(1);
} finally {
System.out.println("Inside finally");
}
}
public void callingRuntimeHalt() {
try {
System.out.println("Inside try");
Runtime.getRuntime()
.halt(1);
} finally {
System.out.println("Inside finally");
}
}
public void infiniteLoop() {
try {
System.out.println("Inside try");
while (true) {
}
} finally {
System.out.println("Inside finally");
}
}
public void daemonThread() throws InterruptedException {
Runnable runnable = () -> {
try {
System.out.println("Inside try");
} finally {
try {
Thread.sleep(1000);
System.out.println("Inside finally");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
Thread regular = new Thread(runnable);
Thread daemon = new Thread(runnable);
daemon.setDaemon(true);
regular.start();
Thread.sleep(300);
daemon.start();
}
}

33
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/PitfallsWhenUsingFinally.java Normal file
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package com.baeldung.finallykeyword;
public class PitfallsWhenUsingFinally {
public String disregardsUnCaughtException() {
try {
System.out.println("Inside try");
throw new RuntimeException();
} finally {
System.out.println("Inside finally");
return "from finally";
}
}
public String ignoringOtherReturns() {
try {
System.out.println("Inside try");
return "from try";
} finally {
System.out.println("Inside finally");
return "from finally";
}
}
public String throwsException() {
try {
System.out.println("Inside try");
return "from try";
} finally {
throw new RuntimeException();
}
}
}

49
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/methodmultiplereturnvalues/Coordinates.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
public class Coordinates {
private double longitude;
private double latitude;
private String placeName;
public Coordinates() {}
public Coordinates(double longitude, double latitude, String placeName) {
this.longitude = longitude;
this.latitude = latitude;
this.placeName = placeName;
}
public double calculateDistance(Coordinates c) {
double s1 = Math.abs(this.longitude - c.longitude);
double s2 = Math.abs(this.latitude - c.latitude);
return Math.hypot(s1, s2);
}
public double getLongitude() {
return longitude;
}
public void setLongitude(double longitude) {
this.longitude = longitude;
}
public double getLatitude() {
return latitude;
}
public void setLatitude(double latitude) {
this.latitude = latitude;
}
public String getPlaceName() {
return placeName;
}
public void setPlaceName(String placeName) {
this.placeName = placeName;
}
}

27
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingArrays.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
class MultipleReturnValuesUsingArrays {
static double[] getCoordinatesDoubleArray() {
double[] coordinates = new double[2];
coordinates[0] = 10;
coordinates[1] = 12.5;
return coordinates;
}
static Number[] getCoordinatesNumberArray() {
Number[] coordinates = new Number[2];
coordinates[0] = 10; //Integer
coordinates[1] = 12.5; //Double
return coordinates;
}
}

30
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingCollections.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
class MultipleReturnValuesUsingCollections {
static List<Number> getCoordinatesList() {
List<Number> coordinates = new ArrayList<>();
coordinates.add(10);
coordinates.add(12.5);
return coordinates;
}
static Map<String, Number> getCoordinatesMap() {
Map<String, Number> coordinates = new HashMap<>();
coordinates.put("longitude", 10);
coordinates.put("latitude", 12.5);
return coordinates;
}
}

14
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingContainer.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
class MultipleReturnValuesUsingContainer {
static Coordinates getCoordinates() {
double longitude = 10;
double latitude = 12.5;
String placeName = "home";
return new Coordinates(longitude, latitude, placeName);
}
}

17
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingTuples.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
import java.util.List;
class MultipleReturnValuesUsingTuples {
static Tuple2<Coordinates, Double> getMostDistantPoint(List<Coordinates> coordinatesList,
Coordinates target) {
return coordinatesList.stream()
.map(coor -> new Tuple2<>(coor, coor.calculateDistance(target)))
.max((d1, d2) -> Double.compare(d1.getSecond(), d2.getSecond()))
.get();
}
}

31
core-java-modules/core-java-lang-2/src/main/java/com/baeldung/methodmultiplereturnvalues/Tuple2.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
public class Tuple2 <K, V> {
private K first;
private V second;
public Tuple2() {}
public Tuple2(K first, V second) {
this.first = first;
this.second = second;
}
public K getFirst() {
return first;
}
public V getSecond() {
return second;
}
public void setFirst(K first) {
this.first = first;
}
public void setSecond(V second) {
this.second = second;
}
}

27
core-java-modules/core-java-lang-2/src/test/java/com/baeldung/finallykeyword/PitfallsWhenUsingFinallyUnitTest.java Normal file
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package com.baeldung.finallykeyword;
import static org.junit.Assert.*;
import org.junit.Test;
public class PitfallsWhenUsingFinallyUnitTest {
PitfallsWhenUsingFinally instance = new PitfallsWhenUsingFinally();
@Test
public void testIgnoresException() {
String result = instance.disregardsUnCaughtException();
assertEquals("from finally", result);
}
@Test
public void testIgnoresOtherReturns() {
String result = instance.ignoringOtherReturns();
assertEquals("from finally", result);
}
@Test(expected = RuntimeException.class)
public void testThrowsException() {
instance.throwsException();
}
}

25
core-java-modules/core-java-lang-2/src/test/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingArraysUnitTest.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
class MultipleReturnValuesUsingArraysUnitTest {
@Test
void whenUsingArrayOfDoubles_thenMultipleDoubleFieldsAreReturned() {
double[] coordinates = MultipleReturnValuesUsingArrays.getCoordinatesDoubleArray();
assertEquals(10, coordinates[0]);
assertEquals(12.5, coordinates[1]);
}
@Test
void whenUsingArrayOfNumbers_thenMultipleNumberFieldsAreReturned() {
Number[] coordinates = MultipleReturnValuesUsingArrays.getCoordinatesNumberArray();
assertEquals(10, coordinates[0]);
assertEquals(12.5, coordinates[1]);
}
}

25
core-java-modules/core-java-lang-2/src/test/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingCollectionsUnitTest.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.util.List;
import java.util.Map;
import org.junit.jupiter.api.Test;
class MultipleReturnValuesUsingCollectionsUnitTest {
@Test
void whenUsingList_thenMultipleFieldsAreReturned() {
List<Number> coordinates = MultipleReturnValuesUsingCollections.getCoordinatesList();
assertEquals(Integer.valueOf(10), coordinates.get(0));
assertEquals(Double.valueOf(12.5), coordinates.get(1));
}
@Test
void whenUsingMap_thenMultipleFieldsAreReturned() {
Map<String, Number> coordinates = MultipleReturnValuesUsingCollections.getCoordinatesMap();
assertEquals(Integer.valueOf(10), coordinates.get("longitude"));
assertEquals(Double.valueOf(12.5), coordinates.get("latitude"));
}
}

17
core-java-modules/core-java-lang-2/src/test/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingContainerUnitTest.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
class MultipleReturnValuesUsingContainerUnitTest {
@Test
void whenUsingContainerClass_thenMultipleFieldsAreReturned() {
Coordinates coordinates = MultipleReturnValuesUsingContainer.getCoordinates();
assertEquals(10, coordinates.getLongitude());
assertEquals(12.5, coordinates.getLatitude());
assertEquals("home", coordinates.getPlaceName());
}
}

31
core-java-modules/core-java-lang-2/src/test/java/com/baeldung/methodmultiplereturnvalues/MultipleReturnValuesUsingTuplesUnitTest.java Normal file
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package com.baeldung.methodmultiplereturnvalues;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.List;
import org.junit.jupiter.api.Test;
class MultipleReturnValuesUsingTuplesUnitTest {
@Test
void whenUsingTuple_thenMultipleFieldsAreReturned() {
List<Coordinates> coordinatesList = new ArrayList<>();
coordinatesList.add(new Coordinates(1, 1, "home"));
coordinatesList.add(new Coordinates(2, 2, "school"));
coordinatesList.add(new Coordinates(3, 3, "hotel"));
Coordinates target = new Coordinates(5, 5, "gym");
Tuple2<Coordinates, Double> mostDistantPoint = MultipleReturnValuesUsingTuples.getMostDistantPoint(coordinatesList, target);
assertEquals(1, mostDistantPoint.getFirst().getLongitude());
assertEquals(1, mostDistantPoint.getFirst().getLatitude());
assertEquals("home", mostDistantPoint.getFirst().getPlaceName());
assertEquals(5.66, BigDecimal.valueOf(mostDistantPoint.getSecond()).setScale(2, RoundingMode.HALF_UP).doubleValue());
}
}

302
core-java-modules/core-java-lang-math/src/main/java/com/baeldung/powerset/PowerSetUtility.java Normal file
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package com.baeldung.powerset;
import javax.annotation.Nullable;
import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
public class PowerSetUtility<T> {
private Map<T, Integer> map = new HashMap<>();
private List<T> reverseMap = new ArrayList<>();
//Lazy Load PowerSet class
private static class PowerSet<E> extends AbstractSet<Set<E>> {
private Map<E, Integer> map = new HashMap<>();
private List<E> reverseMap = new ArrayList<>();
private Set<E> set;
public PowerSet(Set<E> set) {
this.set = set;
initializeMap();
}
abstract class ListIterator<K> implements Iterator<K> {
protected int position = 0;
private int size;
public ListIterator(int size) {
this.size = size;
}
@Override
public boolean hasNext() {
return position < size;
}
}
static class Subset<E> extends AbstractSet<E> {
private Map<E, Integer> map;
private List<E> reverseMap;
private int mask;
public Subset(Map<E, Integer> map, List<E> reverseMap, int mask) {
this.map = map;
this.reverseMap = reverseMap;
this.mask = mask;
}
@Override
public Iterator<E> iterator() {
return new Iterator<E>() {
int remainingSetBits = mask;
@Override
public boolean hasNext() {
return remainingSetBits != 0;
}
@Override
public E next() {
int index = Integer.numberOfTrailingZeros(remainingSetBits);
if (index == 32) {
throw new NoSuchElementException();
}
remainingSetBits &= ~(1 << index);
return reverseMap.get(index);
}
};
}
@Override
public int size() {
return Integer.bitCount(mask);
}
@Override
public boolean contains(@Nullable Object o) {
Integer index = map.get(o);
return index != null && (mask & (1 << index)) != 0;
}
}
@Override
public Iterator<Set<E>> iterator() {
return new ListIterator<Set<E>>(this.size()) {
@Override
public Set<E> next() {
return new Subset<>(map, reverseMap, position++);
}
};
}
@Override
public int size() {
return (1 << this.set.size());
}
@Override
public boolean contains(@Nullable Object obj) {
if (obj instanceof Set) {
Set<?> set = (Set<?>) obj;
return reverseMap.containsAll(set);
}
return false;
}
@Override
public boolean equals(@Nullable Object obj) {
if (obj instanceof PowerSet) {
PowerSet<?> that = (PowerSet<?>) obj;
return set.equals(that.set);//Set equals check to have the same element regardless of the order of the items
}
return super.equals(obj);
}
private void initializeMap() {
int mapId = 0;
for (E c : this.set) {
map.put(c, mapId++);
reverseMap.add(c);
}
}
}
public Set<Set<T>> lazyLoadPowerSet(Set<T> set) {
return new PowerSet<>(set);
}
public Set<Set<T>> recursivePowerSet(Set<T> set) {
if (set.isEmpty()) {
Set<Set<T>> ret = new HashSet<>();
ret.add(set);
return ret;
}
T element = set.iterator().next();
Set<T> subSetWithoutElement = getSubSetWithoutElement(set, element);
Set<Set<T>> powerSetSubSetWithoutElement = recursivePowerSet(subSetWithoutElement);
Set<Set<T>> powerSetSubSetWithElement = addElementToAll(powerSetSubSetWithoutElement, element);
Set<Set<T>> powerSet = new HashSet<>();
powerSet.addAll(powerSetSubSetWithoutElement);
powerSet.addAll(powerSetSubSetWithElement);
return powerSet;
}
public Set<Set<T>> recursivePowerSetIndexRepresentation(Collection<T> set) {
initializeMap(set);
Set<Set<Integer>> powerSetIndices = recursivePowerSetIndexRepresentation(0, set.size());
return unMapIndex(powerSetIndices);
}
private List<List<Boolean>> iterativePowerSetByLoopOverNumbers(int n) {
List<List<Boolean>> powerSet = new ArrayList<>();
for (int i = 0; i < (1 << n); i++) {
List<Boolean> subset = new ArrayList<>(n);
for (int j = 0; j < n; j++)
subset.add(((1 << j) & i) > 0);
powerSet.add(subset);
}
return powerSet;
}
private List<List<Boolean>> iterativePowerSetByLoopOverNumbersWithMinimalChange(int n) {
List<List<Boolean>> powerSet = new ArrayList<>();
for (int i = 0; i < (1 << n); i++) {
List<Boolean> subset = new ArrayList<>(n);
for (int j = 0; j < n; j++) {
int grayEquivalent = i ^ (i >> 1);
subset.add(((1 << j) & grayEquivalent) > 0);
}
powerSet.add(subset);
}
return powerSet;
}
public Set<Set<T>> recursivePowerSetBinaryRepresentation(Collection<T> set) {
initializeMap(set);
Set<List<Boolean>> powerSetBoolean = recursivePowerSetBinaryRepresentation(0, set.size());
return unMapBinary(powerSetBoolean);
}
public List<List<T>> iterativePowerSetByLoopOverNumbers(Set<T> set) {
initializeMap(set);
List<List<Boolean>> sets = iterativePowerSetByLoopOverNumbers(set.size());
return unMapListBinary(sets);
}
public List<List<T>> iterativePowerSetByLoopOverNumbersMinimalChange(Set<T> set) {
initializeMap(set);
List<List<Boolean>> sets = iterativePowerSetByLoopOverNumbersWithMinimalChange(set.size());
return unMapListBinary(sets);
}
private Set<Set<Integer>> recursivePowerSetIndexRepresentation(int idx, int n) {
if (idx == n) {
Set<Set<Integer>> empty = new HashSet<>();
empty.add(new HashSet<>());
return empty;
}
Set<Set<Integer>> powerSetSubset = recursivePowerSetIndexRepresentation(idx + 1, n);
Set<Set<Integer>> powerSet = new HashSet<>(powerSetSubset);
for (Set<Integer> s : powerSetSubset) {
HashSet<Integer> subSetIdxInclusive = new HashSet<>(s);
subSetIdxInclusive.add(idx);
powerSet.add(subSetIdxInclusive);
}
return powerSet;
}
private Set<List<Boolean>> recursivePowerSetBinaryRepresentation(int idx, int n) {
if (idx == n) {
Set<List<Boolean>> powerSetOfEmptySet = new HashSet<>();
powerSetOfEmptySet.add(Arrays.asList(new Boolean[n]));
return powerSetOfEmptySet;
}
Set<List<Boolean>> powerSetSubset = recursivePowerSetBinaryRepresentation(idx + 1, n);
Set<List<Boolean>> powerSet = new HashSet<>();
for (List<Boolean> s : powerSetSubset) {
List<Boolean> subSetIdxExclusive = new ArrayList<>(s);
subSetIdxExclusive.set(idx, false);
powerSet.add(subSetIdxExclusive);
List<Boolean> subSetIdxInclusive = new ArrayList<>(s);
subSetIdxInclusive.set(idx, true);
powerSet.add(subSetIdxInclusive);
}
return powerSet;
}
private void initializeMap(Collection<T> collection) {
int mapId = 0;
for (T c : collection) {
map.put(c, mapId++);
reverseMap.add(c);
}
}
private Set<Set<T>> unMapIndex(Set<Set<Integer>> sets) {
Set<Set<T>> ret = new HashSet<>();
for (Set<Integer> s : sets) {
HashSet<T> subset = new HashSet<>();
for (Integer i : s)
subset.add(reverseMap.get(i));
ret.add(subset);
}
return ret;
}
private Set<Set<T>> unMapBinary(Collection<List<Boolean>> sets) {
Set<Set<T>> ret = new HashSet<>();
for (List<Boolean> s : sets) {
HashSet<T> subset = new HashSet<>();
for (int i = 0; i < s.size(); i++)
if (s.get(i))
subset.add(reverseMap.get(i));
ret.add(subset);
}
return ret;
}
private List<List<T>> unMapListBinary(Collection<List<Boolean>> sets) {
List<List<T>> ret = new ArrayList<>();
for (List<Boolean> s : sets) {
List<T> subset = new ArrayList<>();
for (int i = 0; i < s.size(); i++)
if (s.get(i))
subset.add(reverseMap.get(i));
ret.add(subset);
}
return ret;
}
private Set<Set<T>> addElementToAll(Set<Set<T>> powerSetSubSetWithoutElement, T element) {
Set<Set<T>> powerSetSubSetWithElement = new HashSet<>();
for (Set<T> subsetWithoutElement : powerSetSubSetWithoutElement) {
Set<T> subsetWithElement = new HashSet<>(subsetWithoutElement);
subsetWithElement.add(element);
powerSetSubSetWithElement.add(subsetWithElement);
}
return powerSetSubSetWithElement;
}
private Set<T> getSubSetWithoutElement(Set<T> set, T element) {
Set<T> subsetWithoutElement = new HashSet<>();
for (T s : set) {
if (!s.equals(element))
subsetWithoutElement.add(s);
}
return subsetWithoutElement;
}
}

189
core-java-modules/core-java-lang-math/src/test/java/com/baeldung/powerset/PowerSetUtilityUnitTest.java Normal file
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package com.baeldung.powerset;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import org.hamcrest.MatcherAssert;
import org.hamcrest.Matchers;
import org.hamcrest.collection.IsCollectionWithSize;
import org.junit.Test;
import org.junit.jupiter.api.Assertions;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
public class PowerSetUtilityUnitTest {
@Test
public void givenSet_WhenGuavaLibraryGeneratePowerSet_ThenItContainsAllSubsets() {
ImmutableSet<String> set = ImmutableSet.of("APPLE", "ORANGE", "MANGO");
Set<Set<String>> powerSet = Sets.powerSet(set);
Assertions.assertEquals((1 << set.size()), powerSet.size());
MatcherAssert.assertThat(powerSet, Matchers.containsInAnyOrder(
ImmutableSet.of(),
ImmutableSet.of("APPLE"),
ImmutableSet.of("ORANGE"),
ImmutableSet.of("APPLE", "ORANGE"),
ImmutableSet.of("MANGO"),
ImmutableSet.of("APPLE", "MANGO"),
ImmutableSet.of("ORANGE", "MANGO"),
ImmutableSet.of("APPLE", "ORANGE", "MANGO")
));
}
@Test
public void givenSet_WhenPowerSetIsLazyLoadGenerated_ThenItContainsAllSubsets() {
Set<String> set = RandomSetOfStringGenerator.generateRandomSet();
Set<Set<String>> powerSet = new PowerSetUtility<String>().lazyLoadPowerSet(set);
//To make sure that the size of power set is (2 power n)
MatcherAssert.assertThat(powerSet, IsCollectionWithSize.hasSize((1 << set.size())));
//To make sure that number of occurrence of each element is (2 power n-1)
Map<String, Integer> counter = new HashMap<>();
for (Set<String> subset : powerSet) {
for (String name : subset) {
int num = counter.getOrDefault(name, 0);
counter.put(name, num + 1);
}
}
counter.forEach((k, v) -> Assertions.assertEquals((1 << (set.size() - 1)), v.intValue()));
}
@Test
public void givenSet_WhenPowerSetIsCalculated_ThenItContainsAllSubsets() {
Set<String> set = RandomSetOfStringGenerator.generateRandomSet();
Set<Set<String>> powerSet = new PowerSetUtility<String>().recursivePowerSet(set);
//To make sure that the size of power set is (2 power n)
MatcherAssert.assertThat(powerSet, IsCollectionWithSize.hasSize((1 << set.size())));
//To make sure that number of occurrence of each element is (2 power n-1)
Map<String, Integer> counter = new HashMap<>();
for (Set<String> subset : powerSet) {
for (String name : subset) {
int num = counter.getOrDefault(name, 0);
counter.put(name, num + 1);
}
}
counter.forEach((k, v) -> Assertions.assertEquals((1 << (set.size() - 1)), v.intValue()));
}
@Test
public void givenSet_WhenPowerSetIsCalculatedRecursiveByIndexRepresentation_ThenItContainsAllSubsets() {
Set<String> set = RandomSetOfStringGenerator.generateRandomSet();
Set<Set<String>> powerSet = new PowerSetUtility<String>().recursivePowerSetIndexRepresentation(set);
//To make sure that the size of power set is (2 power n)
MatcherAssert.assertThat(powerSet, IsCollectionWithSize.hasSize((1 << set.size())));
//To make sure that number of occurrence of each element is (2 power n-1)
Map<String, Integer> counter = new HashMap<>();
for (Set<String> subset : powerSet) {
for (String name : subset) {
int num = counter.getOrDefault(name, 0);
counter.put(name, num + 1);
}
}
counter.forEach((k, v) -> Assertions.assertEquals((1 << (set.size() - 1)), v.intValue()));
}
@Test
public void givenSet_WhenPowerSetIsCalculatedRecursiveByBinaryRepresentation_ThenItContainsAllSubsets() {
Set<String> set = RandomSetOfStringGenerator.generateRandomSet();
Set<Set<String>> powerSet = new PowerSetUtility<String>().recursivePowerSetBinaryRepresentation(set);
//To make sure that the size of power set is (2 power n)
MatcherAssert.assertThat(powerSet, IsCollectionWithSize.hasSize((1 << set.size())));
//To make sure that number of occurrence of each element is (2 power n-1)
Map<String, Integer> counter = new HashMap<>();
for (Set<String> subset : powerSet) {
for (String name : subset) {
int num = counter.getOrDefault(name, 0);
counter.put(name, num + 1);
}
}
counter.forEach((k, v) -> Assertions.assertEquals((1 << (set.size() - 1)), v.intValue()));
}
@Test
public void givenSet_WhenPowerSetIsCalculatedIterativePowerSetByLoopOverNumbers_ThenItContainsAllSubsets() {
Set<String> set = RandomSetOfStringGenerator.generateRandomSet();
List<List<String>> powerSet = new PowerSetUtility<String>().iterativePowerSetByLoopOverNumbers(set);
//To make sure that the size of power set is (2 power n)
MatcherAssert.assertThat(powerSet, IsCollectionWithSize.hasSize((1 << set.size())));
//To make sure that number of occurrence of each element is (2 power n-1)
Map<String, Integer> counter = new HashMap<>();
for (List<String> subset : powerSet) {
for (String name : subset) {
int num = counter.getOrDefault(name, 0);
counter.put(name, num + 1);
}
}
counter.forEach((k, v) -> Assertions.assertEquals((1 << (set.size() - 1)), v.intValue()));
//To make sure that one subset is not generated twice
Assertions.assertEquals(powerSet.size(), new HashSet<>(powerSet).size());
//To make sure that each element in each subset is occurred once
for (List<String> subset : powerSet) {
Assertions.assertEquals(subset.size(), new HashSet<>(subset).size());
}
}
@Test
public void givenSet_WhenPowerSetIsCalculatedIterativePowerSetByLoopOverNumbersWithMinimalChange_ThenItContainsAllSubsets() {
Set<String> set = RandomSetOfStringGenerator.generateRandomSet();
List<List<String>> powerSet = new PowerSetUtility<String>().iterativePowerSetByLoopOverNumbersMinimalChange(set);
//To make sure that the size of power set is (2 power n)
MatcherAssert.assertThat(powerSet, IsCollectionWithSize.hasSize((1 << set.size())));
//To make sure that number of occurrence of each element is (2 power n-1)
Map<String, Integer> counter = new HashMap<>();
for (List<String> subset : powerSet) {
for (String name : subset) {
int num = counter.getOrDefault(name, 0);
counter.put(name, num + 1);
}
}
counter.forEach((k, v) -> Assertions.assertEquals((1 << (set.size() - 1)), v.intValue()));
//To make sure that one subset is not generated twice
Assertions.assertEquals(powerSet.size(), new HashSet<>(powerSet).size());
//To make sure that each element in each subset is occurred once
for (List<String> subset : powerSet) {
Assertions.assertEquals(subset.size(), new HashSet<>(subset).size());
}
//To make sure that difference of consecutive subsets is exactly 1
for(int i=1; i<powerSet.size(); i++) {
int diff = 0;
for (String s : powerSet.get(i - 1))
if (!powerSet.get(i).contains(s))
diff++;
for (String s : powerSet.get(i))
if (!powerSet.get(i - 1).contains(s))
diff++;
Assertions.assertEquals(1, diff);
}
}
static class RandomSetOfStringGenerator {
private static List<String> fruits = Arrays.asList("Apples", "Avocados", "Banana", "Blueberry", "Cherry", "Clementine", "Cucumber", "Date", "Fig",
"Grapefruit"/*, "Grape", "Kiwi", "Lemon", "Mango", "Mulberry", "Melon", "Nectarine", "Olive", "Orange"*/);
static Set<String> generateRandomSet() {
Set<String> set = new HashSet<>();
Random random = new Random();
int size = random.nextInt(fruits.size());
while (set.size() != size) {
set.add(fruits.get(random.nextInt(fruits.size())));
}
return set;
}
}
}

6
core-java-modules/core-java-lang-operators/src/test/java/com/baeldung/ternaryoperator/TernaryOperatorUnitTest.java
View File

@@ -6,7 +6,7 @@ import org.junit.Test;
public class TernaryOperatorUnitTest {
@Test
public void givenACondition_whenUsingTernaryOperator_thenItEvaluatesConditionAndReturnsAValue() {
public void whenUsingTernaryOperator_thenConditionIsEvaluatedAndValueReturned() {
int number = 10;
String msg = number > 10 ? "Number is greater than 10" : "Number is less than or equal to 10";
@@ -14,7 +14,7 @@ public class TernaryOperatorUnitTest {
}
@Test
public void givenATrueCondition_whenUsingTernaryOperator_thenOnlyExpression1IsEvaluated() {
public void whenConditionIsTrue_thenOnlyFirstExpressionIsEvaluated() {
int exp1 = 0, exp2 = 0;
int result = 12 > 10 ? ++exp1 : ++exp2;
@@ -24,7 +24,7 @@ public class TernaryOperatorUnitTest {
}
@Test
public void givenAFalseCondition_whenUsingTernaryOperator_thenOnlyExpression2IsEvaluated() {
public void whenConditionIsFalse_thenOnlySecondExpressionIsEvaluated() {
int exp1 = 0, exp2 = 0;
int result = 8 > 10 ? ++exp1 : ++exp2;

57
core-java-modules/core-java-perf/src/test/java/com/baeldung/branchprediction/CombiningUnitTest.java Normal file
View File

@@ -0,0 +1,57 @@
package com.baeldung.branchprediction;
import java.util.stream.LongStream;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class CombiningUnitTest {
private static final Logger LOG = LoggerFactory.getLogger(CombiningUnitTest.class);
public static final int TOP = 10000000;
public static final double FRACTION = 0.1;
@Test
public void combined() {
long[] first = LongStream.range(0, TOP)
.map(n -> Math.random() < FRACTION ? 0 : n)
.toArray();
long[] second = LongStream.range(0, TOP)
.map(n -> Math.random() < FRACTION ? 0 : n)
.toArray();
long count = 0;
long start = System.currentTimeMillis();
for (int i = 0; i < TOP; i++) {
if (first[i] * second[i] != 0) {
++count;
}
}
long end = System.currentTimeMillis();
LOG.info("Counted {}/{} numbers using combined mode in {}ms", count, TOP, end - start);
}
@Test
public void separate() {
long[] first = LongStream.range(0, TOP)
.map(n -> Math.random() < FRACTION ? 0 : n)
.toArray();
long[] second = LongStream.range(0, TOP)
.map(n -> Math.random() < FRACTION ? 0 : n)
.toArray();
long count = 0;
long start = System.currentTimeMillis();
for (int i = 0; i < TOP; i++) {
if (first[i] != 0 && second[i] != 0) {
++count;
}
}
long end = System.currentTimeMillis();
LOG.info("Counted {}/{} numbers using separate mode in {}ms", count, TOP, end - start);
}
}

92
core-java-modules/core-java-perf/src/test/java/com/baeldung/branchprediction/IfUnitTest.java Normal file
View File

@@ -0,0 +1,92 @@
package com.baeldung.branchprediction;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.LongStream;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class IfUnitTest {
private static final Logger LOG = LoggerFactory.getLogger(IfUnitTest.class);
public static final int TOP = 10000000;
@Test
public void majorBranchSorted() {
test(TOP, 0.9, false);
}
@Test
public void minorBranchSorted() {
test(TOP, 0.1, false);
}
@Test
public void equalBranchSorted() {
test(TOP, 0.5, false);
}
@Test
public void allBranchSorted() {
test(TOP, 1, false);
}
@Test
public void noneBranchSorted() {
test(TOP, 0, false);
}
@Test
public void majorBranchShuffled() {
test(TOP, 0.9, true);
}
@Test
public void minorBranchShuffled() {
test(TOP, 0.1, true);
}
@Test
public void equalBranchShuffled() {
test(TOP, 0.5, true);
}
@Test
public void allBranchShuffled() {
test(TOP, 1, true);
}
@Test
public void noneBranchShuffled() {
test(TOP, 0, true);
}
private void test(long top, double cutoffPercentage, boolean shuffle) {
List<Long> numbers = LongStream.range(0, top)
.boxed()
.collect(Collectors.toList());
if (shuffle) {
Collections.shuffle(numbers);
}
long cutoff = (long)(top * cutoffPercentage);
long low = 0;
long high = 0;
long start = System.currentTimeMillis();
for (Long number : numbers) {
if (number < cutoff) {
++low;
} else {
++high;
}
}
long end = System.currentTimeMillis();
LOG.info("Counted {}/{} {} numbers in {}ms", low, high, shuffle ? "shuffled" : "sorted", end - start);
}
}

60
core-java-modules/core-java-perf/src/test/java/com/baeldung/branchprediction/SortingUnitTest.java Normal file
View File

@@ -0,0 +1,60 @@
package com.baeldung.branchprediction;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.LongStream;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class SortingUnitTest {
private static final Logger LOG = LoggerFactory.getLogger(SortingUnitTest.class);
public static final int BIG = 10000000;
public static final int SMALL = 100000;
@Test
public void sortedBig() {
test(BIG, false);
}
@Test
public void shuffledBig() {
test(BIG, true);
}
@Test
public void sortedSmall() {
test(SMALL, false);
}
@Test
public void shuffledSmall() {
test(SMALL, true);
}
private void test(long top, boolean shuffle) {
List<Long> numbers = LongStream.range(0, top)
.boxed()
.collect(Collectors.toList());
if (shuffle) {
Collections.shuffle(numbers);
}
long cutoff = top / 2;
long count = 0;
long start = System.currentTimeMillis();
for (Long number : numbers) {
if (number < cutoff) {
++count;
}
}
long end = System.currentTimeMillis();
LOG.info("Counted {}/{} {} numbers in {}ms",
count, top, shuffle ? "shuffled" : "sorted", end - start);
}
}

3
core-java-modules/core-java-security-manager/README.md
View File

@@ -1,3 +0,0 @@
### Relevant Articles:
- [Intro to the Java SecurityManager](https://www.baeldung.com/java-security-manager)

16
core-java-modules/core-java-security-manager/pom.xml
View File

@@ -1,16 +0,0 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>core-java-security-manager</artifactId>
<version>0.1.0-SNAPSHOT</version>
<name>core-java-security-manager</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung.core-java-modules</groupId>
<artifactId>core-java-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
</project>

35
core-java-modules/core-java-security-manager/src/test/java/com/baeldung/security/manager/SecurityManagerUnitTest.java
View File

@@ -1,35 +0,0 @@
package com.baeldung.security.manager;
import org.junit.Test;
import java.net.URL;
import java.security.AccessControlException;
import java.util.concurrent.Callable;
public class SecurityManagerUnitTest {
@Test(expected = AccessControlException.class)
public void whenSecurityManagerIsActive_thenNetworkIsNotAccessibleByDefault() throws Exception {
doTest(() -> {
new URL("http://www.google.com").openConnection().connect();
return null;
});
}
@Test(expected = AccessControlException.class)
public void whenUnauthorizedClassTriesToAccessProtectedOperation_thenAnExceptionIsThrown() throws Exception {
doTest(() -> {
new Service().operation();
return null;
});
}
private void doTest(Callable<Void> action) throws Exception {
System.setSecurityManager(new SecurityManager());
try {
action.call();
} finally {
System.setSecurityManager(null);
}
}
}

1
core-java-modules/core-java-security/README.md
View File

@@ -15,4 +15,5 @@ This module contains articles about core Java Security
- [The Java SecureRandom Class](https://www.baeldung.com/java-secure-random)
- [An Introduction to Java SASL](https://www.baeldung.com/java-sasl)
- [A Guide to Java GSS API](https://www.baeldung.com/java-gss)
- [Intro to the Java SecurityManager](https://www.baeldung.com/java-security-manager)

2
core-java-modules/core-java-security-manager/src/main/java/com/baeldung/security/manager/CustomPermission.java → core-java-modules/core-java-security/src/main/java/com/baeldung/securitymanager/CustomPermission.java
View File

@@ -1,4 +1,4 @@
package com.baeldung.security.manager;
package com.baeldung.securitymanager;
import java.security.BasicPermission;

2
core-java-modules/core-java-security-manager/src/main/java/com/baeldung/security/manager/Service.java → core-java-modules/core-java-security/src/main/java/com/baeldung/securitymanager/Service.java
View File

@@ -1,4 +1,4 @@
package com.baeldung.security.manager;
package com.baeldung.securitymanager;
public class Service {

2
core-java-modules/core-java-security/src/test/java/org/baeldung/java/md5/JavaMD5UnitTest.java → core-java-modules/core-java-security/src/test/java/com/baeldung/java/md5/JavaMD5UnitTest.java
View File

@@ -1,4 +1,4 @@
package org.baeldung.java.md5;
package com.baeldung.java.md5;
import static org.assertj.core.api.Assertions.assertThat;

35
core-java-modules/core-java-security/src/test/java/com/baeldung/securitymanager/SecurityManagerUnitTest.java Normal file
View File

@@ -0,0 +1,35 @@
package com.baeldung.securitymanager;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.net.URL;
import java.security.AccessControlException;
public class SecurityManagerUnitTest {
private static final String TESTING_SECURITY_POLICY = "file:src/test/resources/testing.policy";
@Before
public void setUp() {
System.setProperty("java.security.policy", TESTING_SECURITY_POLICY);
System.setSecurityManager(new SecurityManager());
}
@After
public void tearDown() {
System.setSecurityManager(null);
}
@Test(expected = AccessControlException.class)
public void whenSecurityManagerIsActive_thenNetworkIsNotAccessibleByDefault() throws IOException {
new URL("http://www.google.com").openConnection().connect();
}
@Test(expected = AccessControlException.class)
public void whenUnauthorizedClassTriesToAccessProtectedOperation_thenAnExceptionIsThrown() {
new Service().operation();
}
}

5
core-java-modules/core-java-security/src/test/resources/testing.policy Normal file
View File

@@ -0,0 +1,5 @@
grant {
// This is for testing purposes only.
// It allows us to properly reset the security manager after the unit test completes.
permission java.lang.RuntimePermission "setSecurityManager";
};

4
core-java-modules/pom.xml
View File

@@ -49,7 +49,8 @@
<module>core-java-concurrency-basic-2</module>
<module>core-java-concurrency-collections</module>
<module>core-java-date-operations</module>
<module>core-java-date-operations-1</module>
<module>core-java-date-operations-2</module>
<!-- We haven't upgraded to java 9.-->
<!--
<module>core-java-datetime-computations</module>
@@ -98,7 +99,6 @@
<module>core-java-reflection</module>
<module>core-java-security</module>
<module>core-java-security-manager</module>
<module>core-java-streams</module>
<module>core-java-streams-2</module>
<module>core-java-streams-3</module>