[BAEL-9555] - Created a core-java-modules folder
This commit is contained in:
amit2103
13
core-java-modules/core-java-9/src/main/java/.gitignore
vendored
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13
core-java-modules/core-java-9/src/main/java/.gitignore
vendored
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@@ -0,0 +1,13 @@
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*.class
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#folders#
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/target
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/neoDb*
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/data
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/src/main/webapp/WEB-INF/classes
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*/META-INF/*
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# Packaged files #
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*.jar
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*.war
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*.ear
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@@ -0,0 +1,12 @@
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package com.baeldung.java9.aot;
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public class JaotCompilation {
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public static void main(String[] argv) {
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System.out.println(message());
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}
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public static String message() {
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return "The JAOT compiler says 'Hello'";
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}
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}
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@@ -0,0 +1,23 @@
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package com.baeldung.java9.language;
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public interface PrivateInterface {
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private static String staticPrivate() {
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return "static private";
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}
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private String instancePrivate() {
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return "instance private";
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}
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public default void check() {
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String result = staticPrivate();
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if (!result.equals("static private"))
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throw new AssertionError("Incorrect result for static private interface method");
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PrivateInterface pvt = new PrivateInterface() {
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};
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result = pvt.instancePrivate();
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if (!result.equals("instance private"))
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throw new AssertionError("Incorrect result for instance private interface method");
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}
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}
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@@ -0,0 +1,27 @@
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package com.baeldung.java9.language.stream;
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import static java.util.stream.Collectors.filtering;
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import static java.util.stream.Collectors.groupingBy;
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import static java.util.stream.Collectors.toList;
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import java.util.Collection;
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import java.util.List;
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import java.util.Map;
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import java.util.function.Function;
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public class StreamsGroupingCollectionFilter {
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static public Map<Integer, List<Integer>> findEvenNumbersAfterGroupingByQuantityOfDigits(Collection<Integer> baseCollection) {
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Function<Integer, Integer> getQuantityOfDigits = item -> (int) Math.log10(item) + 1;
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return baseCollection.stream()
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.collect(groupingBy(getQuantityOfDigits, filtering(item -> item % 2 == 0, toList())));
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}
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static public Map<Integer, List<Integer>> findEvenNumbersBeforeGroupingByQuantityOfDigits(Collection<Integer> baseCollection) {
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return baseCollection.stream()
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.filter(item -> item % 2 == 0)
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.collect(groupingBy(item -> (int) Math.log10(item) + 1, toList()));
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}
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}
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@@ -0,0 +1,33 @@
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package com.baeldung.java9.maps.initialize;
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import java.util.AbstractMap;
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import java.util.HashMap;
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import java.util.Map;
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public class MapsInitializer {
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@SuppressWarnings("unused")
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public void createMapWithMapOf() {
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Map<String, String> emptyMap = Map.of();
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Map<String, String> singletonMap = Map.of("key1", "value");
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Map<String, String> map = Map.of("key1","value1", "key2", "value2");
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}
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public void createMapWithMapEntries() {
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Map<String, String> map = Map.ofEntries(
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new AbstractMap.SimpleEntry<String, String>("name", "John"),
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new AbstractMap.SimpleEntry<String, String>("city", "budapest"),
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new AbstractMap.SimpleEntry<String, String>("zip", "000000"),
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new AbstractMap.SimpleEntry<String, String>("home", "1231231231")
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);
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}
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@SuppressWarnings("unused")
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public void createMutableMaps() {
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Map<String, String> map = new HashMap<String, String> (Map.of("key1","value1", "key2", "value2"));
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Map<String, String> map2 = new HashMap<String, String> ( Map.ofEntries(
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new AbstractMap.SimpleEntry<String, String>("name", "John"),
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new AbstractMap.SimpleEntry<String, String>("city", "budapest")));
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}
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}
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@@ -0,0 +1,17 @@
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package com.baeldung.java9.methodhandles;
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public class Book {
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String id;
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String title;
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public Book(String id, String title) {
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this.id = id;
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this.title = title;
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}
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@SuppressWarnings("unused")
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private String formatBook() {
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return id + " > " + title;
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}
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}
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@@ -0,0 +1,24 @@
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package com.baeldung.java9.rangedates;
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import java.util.Collection;
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import java.util.Date;
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public class DatesCollectionIteration {
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public void iteratingRangeOfDatesJava7(Collection<Date> dates) {
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for (Date date : dates) {
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processDate(date);
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}
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}
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public void iteratingRangeOfDatesJava8(Collection<Date> dates) {
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dates.stream()
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.forEach(this::processDate);
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}
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private void processDate(Date date) {
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System.out.println(date);
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}
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}
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@@ -0,0 +1,43 @@
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package com.baeldung.java9.rangedates;
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import java.time.LocalDate;
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import java.util.Calendar;
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import java.util.Date;
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public class RangeDatesIteration {
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public void iterateBetweenDatesJava9(LocalDate startDate, LocalDate endDate) {
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startDate.datesUntil(endDate)
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.forEach(this::processDate);
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}
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public void iterateBetweenDatesJava8(LocalDate start, LocalDate end) {
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for (LocalDate date = start; date.isBefore(end); date = date.plusDays(1)) {
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processDate(date);
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}
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}
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public void iterateBetweenDatesJava7(Date start, Date end) {
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Date current = start;
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while (current.before(end)) {
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processDate(current);
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Calendar calendar = Calendar.getInstance();
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calendar.setTime(current);
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calendar.add(Calendar.DATE, 1);
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current = calendar.getTime();
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}
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}
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private void processDate(LocalDate date) {
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System.out.println(date);
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}
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private void processDate(Date date) {
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System.out.println(date);
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}
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}
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@@ -0,0 +1,82 @@
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package com.baeldung.java9.reactive;
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import java.util.ArrayList;
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import java.util.concurrent.Flow.Subscriber;
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import java.util.concurrent.Flow.Subscription;
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public class BaeldungBatchSubscriberImpl<T> implements Subscriber<String> {
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private Subscription subscription;
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private boolean completed = false;
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private int counter;
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private ArrayList<String> buffer;
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public static final int BUFFER_SIZE = 5;
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public BaeldungBatchSubscriberImpl() {
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buffer = new ArrayList<String>();
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}
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public boolean isCompleted() {
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return completed;
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}
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public void setCompleted(boolean completed) {
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this.completed = completed;
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}
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public int getCounter() {
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return counter;
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}
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public void setCounter(int counter) {
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this.counter = counter;
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}
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@Override
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public void onSubscribe(Subscription subscription) {
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this.subscription = subscription;
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subscription.request(BUFFER_SIZE);
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}
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@Override
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public void onNext(String item) {
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buffer.add(item);
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// if buffer is full, process the items.
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if (buffer.size() >= BUFFER_SIZE) {
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processBuffer();
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}
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//request more items.
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subscription.request(1);
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}
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private void processBuffer() {
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if (buffer.isEmpty())
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return;
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// Process all items in the buffer. Here, we just print it and sleep for 1 second.
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System.out.print("Processed items: ");
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buffer.stream()
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.forEach(item -> {
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System.out.print(" " + item);
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});
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System.out.println();
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try {
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Thread.sleep(1000);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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counter = counter + buffer.size();
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buffer.clear();
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}
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@Override
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public void onError(Throwable t) {
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t.printStackTrace();
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}
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@Override
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public void onComplete() {
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completed = true;
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// process any remaining items in buffer before
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processBuffer();
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subscription.cancel();
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}
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}
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@@ -0,0 +1,55 @@
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package com.baeldung.java9.reactive;
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import java.util.concurrent.Flow.Subscriber;
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import java.util.concurrent.Flow.Subscription;
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public class BaeldungSubscriberImpl<T> implements Subscriber<String> {
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private Subscription subscription;
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private boolean completed = false;
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private int counter;
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public boolean isCompleted() {
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return completed;
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}
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public void setCompleted(boolean completed) {
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this.completed = completed;
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}
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public int getCounter() {
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return counter;
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}
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public void setCounter(int counter) {
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this.counter = counter;
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}
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@Override
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public void onSubscribe(Subscription subscription) {
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this.subscription = subscription;
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subscription.request(1);
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}
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@Override
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public void onNext(String item) {
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try {
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Thread.sleep(1000);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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counter++;
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System.out.println("Processed item : " + item);
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subscription.request(1);
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}
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@Override
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public void onError(Throwable t) {
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t.printStackTrace();
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}
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@Override
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public void onComplete() {
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completed = true;
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subscription.cancel();
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}
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}
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@@ -0,0 +1,44 @@
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package com.baeldung.java9.set;
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import com.google.common.collect.ImmutableSet;
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import java.util.Collections;
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import java.util.HashSet;
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import java.util.Set;
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public class UnmodifiableSet {
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public static void main(String[] args) {
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Set<String> set = new HashSet<>();
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set.add("Canada");
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set.add("USA");
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coreJDK(set);
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guavaOf();
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copyOf(set);
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java9Of();
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}
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private static void java9Of() {
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Set<String> immutable = Set.of("Canada", "USA");
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System.out.println(immutable);
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}
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private static void guavaOf() {
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Set<String> immutable = ImmutableSet.of("Canada", "USA");
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System.out.println(immutable);
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}
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private static void copyOf(Set<String> set) {
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Set<String> immutable = ImmutableSet.copyOf(set);
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set.add("Costa Rica");
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System.out.println(immutable);
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}
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private static void coreJDK(Set<String> set) {
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Set<String> unmodifiableSet = Collections.unmodifiableSet(set);
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set.add("Costa Rica");
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System.out.println(unmodifiableSet);
|
||||
}
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}
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@@ -0,0 +1,84 @@
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package com.baeldung.java9.stackwalker;
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import java.lang.StackWalker.StackFrame;
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import java.util.List;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
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||||
|
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public class StackWalkerDemo {
|
||||
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||||
public void methodOne() {
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||||
this.methodTwo();
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||||
}
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||||
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||||
public void methodTwo() {
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||||
this.methodThree();
|
||||
}
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||||
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||||
public void methodThree() {
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||||
List<StackFrame> stackTrace = StackWalker.getInstance()
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||||
.walk(this::walkExample);
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||||
|
||||
printStackTrace(stackTrace);
|
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|
||||
System.out.println("---------------------------------------------");
|
||||
|
||||
stackTrace = StackWalker.getInstance()
|
||||
.walk(this::walkExample2);
|
||||
|
||||
printStackTrace(stackTrace);
|
||||
|
||||
System.out.println("---------------------------------------------");
|
||||
|
||||
String line = StackWalker.getInstance().walk(this::walkExample3);
|
||||
System.out.println(line);
|
||||
|
||||
System.out.println("---------------------------------------------");
|
||||
|
||||
stackTrace = StackWalker.getInstance(StackWalker.Option.SHOW_REFLECT_FRAMES)
|
||||
.walk(this::walkExample);
|
||||
|
||||
printStackTrace(stackTrace);
|
||||
|
||||
System.out.println("---------------------------------------------");
|
||||
|
||||
Runnable r = () -> {
|
||||
List<StackFrame> stackTrace2 = StackWalker.getInstance(StackWalker.Option.SHOW_HIDDEN_FRAMES)
|
||||
.walk(this::walkExample);
|
||||
printStackTrace(stackTrace2);
|
||||
};
|
||||
r.run();
|
||||
}
|
||||
|
||||
public List<StackFrame> walkExample(Stream<StackFrame> stackFrameStream) {
|
||||
return stackFrameStream.collect(Collectors.toList());
|
||||
}
|
||||
|
||||
public List<StackFrame> walkExample2(Stream<StackFrame> stackFrameStream) {
|
||||
return stackFrameStream.filter(frame -> frame.getClassName()
|
||||
.contains("com.baeldung"))
|
||||
.collect(Collectors.toList());
|
||||
}
|
||||
|
||||
public String walkExample3(Stream<StackFrame> stackFrameStream) {
|
||||
return stackFrameStream.filter(frame -> frame.getClassName()
|
||||
.contains("com.baeldung")
|
||||
&& frame.getClassName()
|
||||
.endsWith("Test"))
|
||||
.findFirst()
|
||||
.map(frame -> frame.getClassName() + "#" + frame.getMethodName() + ", Line " + frame.getLineNumber())
|
||||
.orElse("Unknown caller");
|
||||
}
|
||||
|
||||
public void findCaller() {
|
||||
Class<?> caller = StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE).getCallerClass();
|
||||
System.out.println(caller.getCanonicalName());
|
||||
}
|
||||
|
||||
public void printStackTrace(List<StackFrame> stackTrace) {
|
||||
for (StackFrame stackFrame : stackTrace) {
|
||||
System.out.println(stackFrame.getClassName()
|
||||
.toString() + "#" + stackFrame.getMethodName() + ", Line " + stackFrame.getLineNumber());
|
||||
}
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,43 @@
|
||||
package com.baeldung.java9.streams.reactive;
|
||||
|
||||
import java.util.LinkedList;
|
||||
import java.util.List;
|
||||
import java.util.concurrent.Flow.Subscriber;
|
||||
import java.util.concurrent.Flow.Subscription;
|
||||
import java.util.concurrent.atomic.AtomicInteger;
|
||||
|
||||
public class EndSubscriber<T> implements Subscriber<T> {
|
||||
private final AtomicInteger howMuchMessagesToConsume;
|
||||
private Subscription subscription;
|
||||
public List<T> consumedElements = new LinkedList<>();
|
||||
|
||||
public EndSubscriber(Integer howMuchMessagesToConsume) {
|
||||
this.howMuchMessagesToConsume = new AtomicInteger(howMuchMessagesToConsume);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onSubscribe(Subscription subscription) {
|
||||
this.subscription = subscription;
|
||||
subscription.request(1);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onNext(T item) {
|
||||
howMuchMessagesToConsume.decrementAndGet();
|
||||
System.out.println("Got : " + item);
|
||||
consumedElements.add(item);
|
||||
if (howMuchMessagesToConsume.get() > 0) {
|
||||
subscription.request(1);
|
||||
}
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onError(Throwable t) {
|
||||
t.printStackTrace();
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onComplete() {
|
||||
System.out.println("Done");
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,38 @@
|
||||
package com.baeldung.java9.streams.reactive;
|
||||
|
||||
import java.util.concurrent.Flow;
|
||||
import java.util.concurrent.SubmissionPublisher;
|
||||
import java.util.function.Function;
|
||||
|
||||
public class TransformProcessor<T, R> extends SubmissionPublisher<R> implements Flow.Processor<T, R> {
|
||||
|
||||
private Function<T, R> function;
|
||||
private Flow.Subscription subscription;
|
||||
|
||||
public TransformProcessor(Function<T, R> function) {
|
||||
super();
|
||||
this.function = function;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onSubscribe(Flow.Subscription subscription) {
|
||||
this.subscription = subscription;
|
||||
subscription.request(1);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onNext(T item) {
|
||||
submit(function.apply(item));
|
||||
subscription.request(1);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onError(Throwable t) {
|
||||
t.printStackTrace();
|
||||
}
|
||||
|
||||
@Override
|
||||
public void onComplete() {
|
||||
close();
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,16 @@
|
||||
package com.baeldung.multireleaseapp;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
public class App {
|
||||
|
||||
private static final Logger logger = LoggerFactory.getLogger(App.class);
|
||||
|
||||
public static void main(String[] args) throws Exception {
|
||||
String dateToCheck = args[0];
|
||||
boolean isLeapYear = DateHelper.checkIfLeapYear(dateToCheck);
|
||||
logger.info("Date given " + dateToCheck + " is leap year: " + isLeapYear);
|
||||
}
|
||||
|
||||
}
|
||||
@@ -0,0 +1,22 @@
|
||||
package com.baeldung.multireleaseapp;
|
||||
|
||||
import java.text.SimpleDateFormat;
|
||||
import java.util.Calendar;
|
||||
import java.util.GregorianCalendar;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
public class DateHelper {
|
||||
|
||||
private static final Logger logger = LoggerFactory.getLogger(DateHelper.class);
|
||||
|
||||
public static boolean checkIfLeapYear(String dateStr) throws Exception {
|
||||
logger.info("Checking for leap year using Java 1 calendar API");
|
||||
Calendar cal = Calendar.getInstance();
|
||||
cal.setTime(new SimpleDateFormat("yyyy-MM-dd").parse(dateStr));
|
||||
int year = cal.get(Calendar.YEAR);
|
||||
return (new GregorianCalendar()).isLeapYear(year);
|
||||
}
|
||||
|
||||
}
|
||||
@@ -0,0 +1,26 @@
|
||||
package com.baeldung.optionals;
|
||||
|
||||
import java.util.Optional;
|
||||
|
||||
public class Optionals {
|
||||
|
||||
public static <T> Optional<T> or(Optional<T> optional, Optional<T> fallback) {
|
||||
return optional.isPresent() ? optional : fallback;
|
||||
}
|
||||
|
||||
public static Optional<String> getName(Optional<String> name) {
|
||||
return name.or(() -> getCustomMessage());
|
||||
}
|
||||
|
||||
public static com.google.common.base.Optional<String> getOptionalGuavaName(com.google.common.base.Optional<String> name) {
|
||||
return name.or(getCustomMessageGuava());
|
||||
}
|
||||
|
||||
private static Optional<String> getCustomMessage() {
|
||||
return Optional.of("Name not provided");
|
||||
}
|
||||
|
||||
private static com.google.common.base.Optional<String> getCustomMessageGuava() {
|
||||
return com.google.common.base.Optional.of("Name not provided");
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,18 @@
|
||||
package com.baeldung.multireleaseapp;
|
||||
|
||||
import java.time.LocalDate;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
public class DateHelper {
|
||||
|
||||
private static final Logger logger = LoggerFactory.getLogger(DateHelper.class);
|
||||
|
||||
public static boolean checkIfLeapYear(String dateStr) throws Exception {
|
||||
logger.info("Checking for leap year using Java 9 Date Api");
|
||||
return LocalDate.parse(dateStr)
|
||||
.isLeapYear();
|
||||
}
|
||||
|
||||
}
|
||||
19
core-java-modules/core-java-9/src/main/resources/logback.xml
Normal file
19
core-java-modules/core-java-9/src/main/resources/logback.xml
Normal file
@@ -0,0 +1,19 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<configuration>
|
||||
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
|
||||
<encoder>
|
||||
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
|
||||
</pattern>
|
||||
</encoder>
|
||||
</appender>
|
||||
|
||||
<logger name="org.springframework" level="WARN" />
|
||||
<logger name="org.springframework.transaction" level="WARN" />
|
||||
|
||||
<!-- in order to debug some marshalling issues, this needs to be TRACE -->
|
||||
<logger name="org.springframework.web.servlet.mvc" level="WARN" />
|
||||
|
||||
<root level="INFO">
|
||||
<appender-ref ref="STDOUT" />
|
||||
</root>
|
||||
</configuration>
|
||||
Reference in New Issue
Block a user