Merge branch 'master' into BAEL-16633

This commit is contained in:
Alessio Stalla
2019-10-30 23:09:06 +01:00
170 changed files with 899 additions and 669 deletions

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@@ -8,4 +8,5 @@
- [Java @SafeVarargs Annotation](https://www.baeldung.com/java-safevarargs)
- [Java @Deprecated Annotation](https://www.baeldung.com/java-deprecated)
- [Overview of Java Built-in Annotations](https://www.baeldung.com/java-default-annotations)
- [Creating a Custom Annotation in Java](https://www.baeldung.com/java-custom-annotation)
- [Creating a Custom Annotation in Java](https://www.baeldung.com/java-custom-annotation)
- [Efficient Word Frequency Calculator in Java](https://www.baeldung.com/java-word-frequency)

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@@ -12,4 +12,4 @@
- [Sorting in Java](https://www.baeldung.com/java-sorting)
- [Getting the Size of an Iterable in Java](https://www.baeldung.com/java-iterable-size)
- [Java Null-Safe Streams from Collections](https://www.baeldung.com/java-null-safe-streams-from-collections)
- [Operating on and Removing an Item from Stream](https://www.baeldung.com/java-use-remove-item-stream)

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@@ -11,4 +11,5 @@ This module contains articles about the Java List collection
- [Ways to Iterate Over a List in Java](https://www.baeldung.com/java-iterate-list)
- [Flattening Nested Collections in Java](http://www.baeldung.com/java-flatten-nested-collections)
- [Intersection of Two Lists in Java](https://www.baeldung.com/java-lists-intersection)
- [[<-- Prev]](/core-java-modules/core-java-collections-list)[[Next -->]](/core-java-modules/core-java-collections-list-3)
- [Searching for a String in an ArrayList](https://www.baeldung.com/java-search-string-arraylist)
- [[<-- Prev]](/core-java-modules/core-java-collections-list)[[Next -->]](/core-java-modules/core-java-collections-list-3)

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@@ -12,4 +12,8 @@ This module contains articles about core java exceptions
- [“Sneaky Throws” in Java](https://www.baeldung.com/java-sneaky-throws)
- [The StackOverflowError in Java](https://www.baeldung.com/java-stack-overflow-error)
- [Checked and Unchecked Exceptions in Java](https://www.baeldung.com/java-checked-unchecked-exceptions)
- [Java Try with Resources](https://www.baeldung.com/java-try-with-resources)
- [Java Global Exception Handler](https://www.baeldung.com/java-global-exception-handler)
- [Common Java Exceptions](https://www.baeldung.com/java-common-exceptions)
- [Throw Exception in Optional in Java 8](https://www.baeldung.com/java-optional-throw-exception)
- [How to Find an Exceptions Root Cause in Java](https://www.baeldung.com/java-exception-root-cause)

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@@ -3,4 +3,5 @@
- [Create a File in a Specific Directory in Java](https://www.baeldung.com/java-create-file-in-directory)
- [A Guide to the Java FileReader Class](https://www.baeldung.com/java-filereader)
- [The Java File Class](https://www.baeldung.com/java-io-file)
- [Java FileWriter](https://www.baeldung.com/java-filewriter)

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@@ -7,11 +7,12 @@ This module contains articles about Object-oriented programming (OOP) in Java
- [Access Modifiers in Java](https://www.baeldung.com/java-access-modifiers)
- [Guide to the super Java Keyword](https://www.baeldung.com/java-super)
- [Guide to the this Java Keyword](https://www.baeldung.com/java-this)
- [Java Public Access Modifier](https://www.baeldung.com/java-public-keyword)
- [Java public Access Modifier](https://www.baeldung.com/java-public-keyword)
- [Composition, Aggregation and Association in Java](https://www.baeldung.com/java-composition-aggregation-association)
- [Nested Classes in Java](https://www.baeldung.com/java-nested-classes)
- [A Guide to Inner Interfaces in Java](https://www.baeldung.com/java-inner-interfaces)
- [Java Classes and Objects](https://www.baeldung.com/java-classes-objects)
- [Java Interfaces](https://www.baeldung.com/java-interfaces)
- [Static and Dynamic Binding in Java](https://www.baeldung.com/java-static-dynamic-binding)
- [[<-- Prev]](/core-java-modules/core-java-lang-oop-2)
- [Methods in Java](https://www.baeldung.com/java-methods)
- [[<-- Prev]](/core-java-modules/core-java-lang-oop-2)

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@@ -13,4 +13,7 @@ This module contains articles about core features in the Java language
- [Synthetic Constructs in Java](https://www.baeldung.com/java-synthetic)
- [Retrieving a Class Name in Java](https://www.baeldung.com/java-class-name)
- [Attaching Values to Java Enum](https://www.baeldung.com/java-enum-values)
- [[More --> ]](/core-java-modules/core-java-lang-2)
- [The Java continue and break Keywords](https://www.baeldung.com/java-continue-and-break)
- [A Guide to Java Enums](https://www.baeldung.com/a-guide-to-java-enums)
- [Infinite Loops in Java](https://www.baeldung.com/infinite-loops-java)
- [[More --> ]](/core-java-modules/core-java-lang-2)

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@@ -9,4 +9,5 @@ This module contains articles about networking in Java
- [Using Curl in Java](https://www.baeldung.com/java-curl)
- [Do a Simple HTTP Request in Java](http://www.baeldung.com/java-http-request)
- [Sending Emails with Java](http://www.baeldung.com/java-email)
- [Authentication with HttpUrlConnection](https://www.baeldung.com/java-http-url-connection)
- [[<-- Prev]](/core-java-modules/core-java-networking)

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### Relevant Articles:
- [Intro to the Java SecurityManager](https://www.baeldung.com/java-security-manager)

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@@ -5,5 +5,5 @@ This module contains articles about string conversions from/to another type.
### Relevant Articles:
- [Java String Conversions](https://www.baeldung.com/java-string-conversions)
- [Convert String to Byte Array and Reverse in Java](https://www.baeldung.com/java-string-to-byte-array)
- [Convert Char Array to String](https://www.baeldung.com/java-char-array-to-string)
- [Convert Character Array to String in Java](https://www.baeldung.com/java-char-array-to-string)
- More articles: [[<-- prev]](/core-java-string-conversions)

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## Java String Operations
This module contains articles about string operations.
### Relevant Articles:
- [Concatenating Strings In Java](https://www.baeldung.com/java-strings-concatenation)
- [Checking for Empty or Blank Strings in Java](https://www.baeldung.com/java-blank-empty-strings)
- [String Initialization in Java](https://www.baeldung.com/java-string-initialization)
- [String toLowerCase and toUpperCase Methods in Java](https://www.baeldung.com/java-string-convert-case)
- [Java String equalsIgnoreCase()](https://www.baeldung.com/java-string-equalsignorecase)
- More articles: [[<-- prev]](../core-java-string-operations)

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<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-string-operations-2</artifactId>
<version>0.1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>core-java-string-operations-2</name>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-java</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../../parent-java</relativePath>
</parent>
<dependencies>
<dependency>
<groupId>javax.validation</groupId>
<artifactId>validation-api</artifactId>
<version>${validation-api.version}</version>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>${guava.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>${commons-lang3.version}</version>
</dependency>
<dependency>
<groupId>org.hibernate.validator</groupId>
<artifactId>hibernate-validator</artifactId>
<version>${hibernate-validator.version}</version>
</dependency>
<dependency>
<groupId>javax.el</groupId>
<artifactId>javax.el-api</artifactId>
<version>${javax.el-api.version}</version>
</dependency>
<dependency>
<groupId>org.glassfish.web</groupId>
<artifactId>javax.el</artifactId>
<version>${javax.el.version}</version>
</dependency>
<dependency>
<groupId>org.hamcrest</groupId>
<artifactId>hamcrest-library</artifactId>
<version>${org.hamcrest.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>core-java-string-operations-2</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
</build>
<properties>
<assertj.version>3.6.1</assertj.version>
<validation-api.version>2.0.0.Final</validation-api.version>
<commons-lang3.version>3.8.1</commons-lang3.version>
<guava.version>27.0.1-jre</guava.version>
<hibernate-validator.version>6.0.2.Final</hibernate-validator.version>
<javax.el-api.version>3.0.0</javax.el-api.version>
<javax.el.version>2.2.6</javax.el.version>
</properties>
</project>

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package com.baeldung.emptystrings;
class EmptyStringCheck {
boolean isEmptyString(String string) {
return string == null || string.isEmpty();
}
}

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package com.baeldung.emptystrings;
class Java5EmptyStringCheck {
boolean isEmptyString(String string) {
return string == null || string.length() == 0;
}
}

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package com.baeldung.emptystrings;
class PlainJavaBlankStringCheck {
boolean isBlankString(String string) {
return string == null || string.trim().isEmpty();
}
}

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package com.baeldung.emptystrings;
import javax.validation.constraints.Pattern;
class SomeClassWithValidations {
@Pattern(regexp = "\\A(?!\\s*\\Z).+")
private String someString;
SomeClassWithValidations setSomeString(String someString) {
this.someString = someString;
return this;
}
}

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package com.baeldung.changecase;
import org.junit.Test;
import java.util.Locale;
import static org.junit.Assert.assertEquals;
public class ToLowerCaseUnitTest {
private static final Locale TURKISH = new Locale("tr");
private String name = "John Doe";
private String foreignUppercase = "\u0049";
@Test
public void givenMixedCaseString_WhenToLowerCase_ThenResultIsLowerCase() {
assertEquals("john doe", name.toLowerCase());
}
@Test
public void givenForeignString_WhenToLowerCaseWithoutLocale_ThenResultIsLowerCase() {
assertEquals("\u0069", foreignUppercase.toLowerCase());
}
@Test
public void givenForeignString_WhenToLowerCaseWithLocale_ThenResultIsLowerCase() {
assertEquals("\u0131", foreignUppercase.toLowerCase(TURKISH));
}
}

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package com.baeldung.changecase;
import org.junit.Test;
import java.util.Locale;
import static org.junit.Assert.assertEquals;
public class ToUpperCaseUnitTest {
private static final Locale TURKISH = new Locale("tr");
private String name = "John Doe";
private String foreignLowercase = "\u0069";
@Test
public void givenMixedCaseString_WhenToUpperCase_ThenResultIsUpperCase() {
assertEquals("JOHN DOE", name.toUpperCase());
}
@Test
public void givenForeignString_WhenToUpperCaseWithoutLocale_ThenResultIsUpperCase() {
assertEquals("\u0049", foreignLowercase.toUpperCase());
}
@Test
public void givenForeignString_WhenToUpperCaseWithLocale_ThenResultIsUpperCase() {
assertEquals("\u0130", foreignLowercase.toUpperCase(TURKISH));
}
}

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package com.baeldung.emptystrings;
import com.google.common.base.Strings;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import java.util.Set;
import static org.hamcrest.Matchers.iterableWithSize;
import static org.junit.Assert.*;
public class EmptyStringsUnitTest {
private String emptyString = "";
private String blankString = " \n\t ";
private String nonEmptyString = " someString ";
/*
* EmptyStringCheck
*/
@Test
public void givenSomeEmptyString_thenEmptyStringCheckIsEmptyStringReturnsTrue() {
assertTrue(new EmptyStringCheck().isEmptyString(emptyString));
}
@Test
public void givenSomeNonEmptyString_thenEmptyStringCheckIsEmptyStringReturnsFalse() {
assertFalse(new EmptyStringCheck().isEmptyString(nonEmptyString));
}
@Test
public void givenSomeBlankString_thenEmptyStringCheckIsEmptyStringReturnsFalse() {
assertFalse(new EmptyStringCheck().isEmptyString(blankString));
}
/*
* Java5EmptyStringCheck
*/
@Test
public void givenSomeEmptyString_thenJava5EmptyStringCheckIsEmptyStringReturnsTrue() {
assertTrue(new Java5EmptyStringCheck().isEmptyString(emptyString));
}
@Test
public void givenSomeNonEmptyString_thenJava5EmptyStringCheckIsEmptyStringReturnsFalse() {
assertFalse(new Java5EmptyStringCheck().isEmptyString(nonEmptyString));
}
@Test
public void givenSomeBlankString_thenJava5EmptyStringCheckIsEmptyStringReturnsFalse() {
assertFalse(new Java5EmptyStringCheck().isEmptyString(blankString));
}
/*
* PlainJavaBlankStringCheck
*/
@Test
public void givenSomeEmptyString_thenPlainJavaBlankStringCheckIsBlankStringReturnsTrue() {
assertTrue(new PlainJavaBlankStringCheck().isBlankString(emptyString));
}
@Test
public void givenSomeNonEmptyString_thenPlainJavaBlankStringCheckIsBlankStringReturnsFalse() {
assertFalse(new PlainJavaBlankStringCheck().isBlankString(nonEmptyString));
}
@Test
public void givenSomeBlankString_thenPlainJavaBlankStringCheckIsBlankStringReturnsTrue() {
assertTrue(new PlainJavaBlankStringCheck().isBlankString(blankString));
}
/*
* Apache Commons Lang StringUtils
*/
@Test
public void givenSomeEmptyString_thenStringUtilsIsBlankReturnsTrue() {
assertTrue(StringUtils.isBlank(emptyString));
}
@Test
public void givenSomeNonEmptyString_thenStringUtilsIsBlankReturnsFalse() {
assertFalse(StringUtils.isBlank(nonEmptyString));
}
@Test
public void givenSomeBlankString_thenStringUtilsIsBlankReturnsTrue() {
assertTrue(StringUtils.isBlank(blankString));
}
/*
* Google Guava Strings
*/
@Test
public void givenSomeEmptyString_thenStringsIsNullOrEmptyStringReturnsTrue() {
assertTrue(Strings.isNullOrEmpty(emptyString));
}
@Test
public void givenSomeNonEmptyString_thenStringsIsNullOrEmptyStringReturnsFalse() {
assertFalse(Strings.isNullOrEmpty(nonEmptyString));
}
@Test
public void givenSomeBlankString_thenStringsIsNullOrEmptyStringReturnsFalse() {
assertFalse(Strings.isNullOrEmpty(blankString));
}
/*
* Bean Validation
*/
private ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
private Validator validator = factory.getValidator();
@Test
public void givenSomeEmptyString_thenBeanValidationReturnsViolations() {
SomeClassWithValidations someClassWithValidations = new SomeClassWithValidations().setSomeString(emptyString);
Set<ConstraintViolation<SomeClassWithValidations>> violations = validator.validate(someClassWithValidations);
assertThat(violations, iterableWithSize(1));
}
@Test
public void givenSomeNonEmptyString_thenBeanValidationValidatesWithoutViolations() {
SomeClassWithValidations someClassWithValidations = new SomeClassWithValidations().setSomeString(nonEmptyString);
Set<ConstraintViolation<SomeClassWithValidations>> violations = validator.validate(someClassWithValidations);
assertThat(violations, iterableWithSize(0));
}
@Test
public void givenSomeBlankString_thenBeanValidationReturnsViolations() {
SomeClassWithValidations someClassWithValidations = new SomeClassWithValidations().setSomeString(blankString);
Set<ConstraintViolation<SomeClassWithValidations>> violations = validator.validate(someClassWithValidations);
assertThat(violations, iterableWithSize(1));
}
}

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package com.baeldung.equalsIgnoreCase;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
import static org.assertj.core.api.Assertions.assertThat;
public class StringEqualsIgnoreCaseUnitTest {
private String string1 = "equals ignore case";
private String string2 = "EQUALS IGNORE CASE";
@Test
public void givenEqualStringsWithDifferentCase_whenUsingEqualsIgnoreCase_ThenTheyAreEqual() {
assertThat(string1.equalsIgnoreCase(string2)).isTrue();
}
@Test
public void givenEqualStringsWithDifferentCase_whenUsingApacheCommonsEqualsIgnoreCase_ThenTheyAreEqual() {
assertThat(StringUtils.equalsIgnoreCase(string1, string2)).isTrue();
}
@Test
public void givenAStringAndNullValue_whenUsingApacheCommonsEqualsIgnoreCase_ThenTheyAreNotEqual() {
assertThat(StringUtils.equalsIgnoreCase(string1, null)).isFalse();
}
}

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package com.baeldung.initialization;
import org.junit.Test;
import static org.junit.Assert.*;
public class StringInitializationUnitTest {
private String fieldString;
void printDeclaredOnlyString() {
String localVarString = null;
System.out.println(localVarString); // compilation error
System.out.println(fieldString);
}
@Test
public void givenDeclaredFeldStringAndNullString_thenCompareEquals() {
String localVarString = null;
assertEquals(fieldString, localVarString);
}
@Test
public void givenTwoStringsWithSameLiteral_thenCompareReferencesEquals() {
String literalOne = "Baeldung";
String literalTwo = "Baeldung";
assertTrue(literalOne == literalTwo);
}
@Test
public void givenTwoStringsUsingNew_thenCompareReferencesNotEquals() {
String newStringOne = new String("Baeldung");
String newStringTwo = new String("Baeldung");
assertFalse(newStringOne == newStringTwo);
}
@Test
public void givenEmptyLiteralStringsAndNewObject_thenCompareEquals() {
String emptyLiteral = "";
String emptyNewString = new String("");
assertEquals(emptyLiteral, emptyNewString);
}
@Test
public void givenEmptyStringObjects_thenCompareEquals() {
String emptyNewString = new String("");
String emptyNewStringTwo = new String();
assertEquals(emptyNewString, emptyNewStringTwo);
}
}

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package com.baeldung.stringconcatenation;
import org.junit.Test;
import java.util.Arrays;
import java.util.List;
import java.util.StringJoiner;
import java.util.stream.Collectors;
import static org.junit.Assert.assertEquals;
public class StringConcatenationUnitTest {
@Test
public void givenMultipleStrings_whenConcatUsingStringBuilder_checkStringCorrect() {
StringBuilder stringBuilder = new StringBuilder(100);
stringBuilder.append("Baeldung");
stringBuilder.append(" is");
stringBuilder.append(" awesome");
assertEquals("Baeldung is awesome", stringBuilder.toString());
}
@Test
public void givenMultipleString_whenConcatUsingAdditionOperator_checkStringCorrect() {
String myString = "The " + "quick " + "brown " + "fox...";
assertEquals("The quick brown fox...", myString);
}
@Test
public void givenMultipleStrings_whenConcatUsingStringFormat_checkStringCorrect() {
String myString = String.format("%s %s %.2f %s %s, %s...", "I",
"ate",
2.5056302,
"blueberry",
"pies",
"oops");
assertEquals("I ate 2.51 blueberry pies, oops...", myString);
}
@Test
public void givenMultipleStrings_whenStringConcatUsed_checkStringCorrect() {
String myString = "Both".concat(" fickle")
.concat(" dwarves")
.concat(" jinx")
.concat(" my")
.concat(" pig")
.concat(" quiz");
assertEquals("Both fickle dwarves jinx my pig quiz", myString);
}
@Test
public void givenMultipleStrings_whenStringJoinUsed_checkStringCorrect() {
String[] strings = {"I'm", "running", "out", "of", "pangrams!"};
String myString = String.join(" ", strings);
assertEquals("I'm running out of pangrams!", myString);
}
@Test
public void givenMultipleStrings_whenStringJoinerUsed_checkStringCorrect() {
StringJoiner fruitJoiner = new StringJoiner(", ");
fruitJoiner.add("Apples");
fruitJoiner.add("Oranges");
fruitJoiner.add("Bananas");
assertEquals("Apples, Oranges, Bananas", fruitJoiner.toString());
}
@Test
public void givenMultipleStrings_whenArrayJoiner_checkStringCorrect() {
String[] myFavouriteLanguages = {"Java", "JavaScript", "Python"};
String toString = Arrays.toString(myFavouriteLanguages);
assertEquals("[Java, JavaScript, Python]", toString);
}
@Test
public void givenArrayListOfStrings_whenCollectorsJoin_checkStringCorrect() {
List<String> awesomeAnimals = Arrays.asList("Shark", "Panda", "Armadillo");
String animalString = awesomeAnimals.stream().collect(Collectors.joining(", "));
assertEquals("Shark, Panda, Armadillo", animalString);
}
}

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## Java String Operations
This module contains articles about string operations.
### Relevant Articles:
- [Comparing Strings in Java](https://www.baeldung.com/java-compare-strings)
- [Check If a String Is Numeric in Java](https://www.baeldung.com/java-check-string-number)
- [Get Substring from String in Java](https://www.baeldung.com/java-substring)
- [Split a String in Java](https://www.baeldung.com/java-split-string)
- [Common String Operations in Java](https://www.baeldung.com/java-string-operations)
- [Java toString() Method](https://www.baeldung.com/java-tostring)
- [String Operations with Java Streams](https://www.baeldung.com/java-stream-operations-on-strings)
- [Adding a Newline Character to a String in Java](https://www.baeldung.com/java-string-newline)
- [Check If a String Contains a Substring](https://www.baeldung.com/java-string-contains-substring)
- [Java Base64 Encoding and Decoding](https://www.baeldung.com/java-base64-encode-and-decode)
- More articles: [[next -->]](../core-java-string-operations-2)

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<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-string-operations</artifactId>
<version>0.1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>core-java-string-operations</name>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-java</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../../parent-java</relativePath>
</parent>
<dependencies>
<dependency>
<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-core.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-generator-annprocess</artifactId>
<version>${jmh-generator.version}</version>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>${commons-codec.version}</version>
</dependency>
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>core-java-string-operations</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
</build>
<properties>
<commons-lang3.version>3.8.1</commons-lang3.version>
<assertj.version>3.6.1</assertj.version>
<commons-codec.version>1.10</commons-codec.version>
</properties>
</project>

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package com.baeldung.isnumeric;
import java.util.concurrent.TimeUnit;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
public class Benchmarking {
public static void main(String[] args) throws RunnerException {
Options opt = new OptionsBuilder().include(Benchmarking.class.getSimpleName())
.forks(1)
.build();
new Runner(opt).run();
}
@State(Scope.Thread)
public static class ExecutionPlan {
public String number = Integer.toString(Integer.MAX_VALUE);
public boolean isNumber = false;
public IsNumeric isNumeric = new IsNumeric();
}
@Benchmark
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public void usingCoreJava(ExecutionPlan plan) {
plan.isNumber = plan.isNumeric.usingCoreJava(plan.number);
}
@Benchmark
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public void usingRegularExpressions(ExecutionPlan plan) {
plan.isNumber = plan.isNumeric.usingRegularExpressions(plan.number);
}
@Benchmark
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public void usingNumberUtils_isCreatable(ExecutionPlan plan) {
plan.isNumber = plan.isNumeric.usingNumberUtils_isCreatable(plan.number);
}
@Benchmark
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public void usingNumberUtils_isParsable(ExecutionPlan plan) {
plan.isNumber = plan.isNumeric.usingNumberUtils_isParsable(plan.number);
}
@Benchmark
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public void usingStringUtils_isNumeric(ExecutionPlan plan) {
plan.isNumber = plan.isNumeric.usingStringUtils_isNumeric(plan.number);
}
@Benchmark
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public void usingStringUtils_isNumericSpace(ExecutionPlan plan) {
plan.isNumber = plan.isNumeric.usingStringUtils_isNumericSpace(plan.number);
}
}

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package com.baeldung.isnumeric;
import java.util.Scanner;
public class CheckIntegerInput {
public static void main(String[] args) {
try (Scanner scanner = new Scanner(System.in)) {
System.out.println("Enter an integer : ");
if (scanner.hasNextInt()) {
System.out.println("You entered : " + scanner.nextInt());
} else {
System.out.println("The input is not an integer");
}
}
}
}

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package com.baeldung.isnumeric;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.math.NumberUtils;
public class IsNumeric {
public boolean usingCoreJava(String strNum) {
try {
Double.parseDouble(strNum);
} catch (NumberFormatException | NullPointerException nfe) {
return false;
}
return true;
}
public boolean usingRegularExpressions(String strNum) {
return strNum.matches("-?\\d+(\\.\\d+)?");
}
public boolean usingNumberUtils_isCreatable(String strNum) {
return NumberUtils.isCreatable(strNum);
}
public boolean usingNumberUtils_isParsable(String strNum) {
return NumberUtils.isParsable(strNum);
}
public boolean usingStringUtils_isNumeric(String strNum) {
return StringUtils.isNumeric(strNum);
}
public boolean usingStringUtils_isNumericSpace(String strNum) {
return StringUtils.isNumericSpace(strNum);
}
}

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package com.baeldung.isnumeric;
import org.apache.log4j.Logger;
public class IsNumericDriver {
private static Logger LOG = Logger.getLogger(IsNumericDriver.class);
private static IsNumeric isNumeric = new IsNumeric();
public static void main(String[] args) {
LOG.info("Testing all methods...");
boolean res = isNumeric.usingCoreJava("1001");
LOG.info("Using Core Java : " + res);
res = isNumeric.usingRegularExpressions("1001");
LOG.info("Using Regular Expressions : " + res);
res = isNumeric.usingNumberUtils_isCreatable("1001");
LOG.info("Using NumberUtils.isCreatable : " + res);
res = isNumeric.usingNumberUtils_isParsable("1001");
LOG.info("Using NumberUtils.isParsable : " + res);
res = isNumeric.usingStringUtils_isNumeric("1001");
LOG.info("Using StringUtils.isNumeric : " + res);
res = isNumeric.usingStringUtils_isNumericSpace("1001");
LOG.info("Using StringUtils.isNumericSpace : " + res);
}
}

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package com.baeldung.newline;
public class AddingNewLineToString {
public static void main(String[] args) {
String line1 = "Humpty Dumpty sat on a wall.";
String line2 = "Humpty Dumpty had a great fall.";
String rhyme = "";
System.out.println("***New Line in a String in Java***");
//1. Using "\n"
System.out.println("1. Using \\n");
rhyme = line1 + "\n" + line2;
System.out.println(rhyme);
//2. Using "\r\n"
System.out.println("2. Using \\r\\n");
rhyme = line1 + "\r\n" + line2;
System.out.println(rhyme);
//3. Using "\r"
System.out.println("3. Using \\r");
rhyme = line1 + "\r" + line2;
System.out.println(rhyme);
//4. Using "\n\r" Note that this is not same as "\r\n"
// Using "\n\r" is equivalent to adding two lines
System.out.println("4. Using \\n\\r");
rhyme = line1 + "\n\r" + line2;
System.out.println(rhyme);
//5. Using System.lineSeparator()
System.out.println("5. Using System.lineSeparator()");
rhyme = line1 + System.lineSeparator() + line2;
System.out.println(rhyme);
//6. Using System.getProperty("line.separator")
System.out.println("6. Using System.getProperty(\"line.separator\")");
rhyme = line1 + System.getProperty("line.separator") + line2;
System.out.println(rhyme);
System.out.println("***HTML to rendered in a browser***");
//1. Line break for HTML using <br>
System.out.println("1. Line break for HTML using <br>");
rhyme = line1 + "<br>" + line2;
System.out.println(rhyme);
//2. Line break for HTML using “&#10;”
System.out.println("2. Line break for HTML using &#10;");
rhyme = line1 + "&#10;" + line2;
System.out.println(rhyme);
//3. Line break for HTML using “&#13;”
System.out.println("3. Line break for HTML using &#13;");
rhyme = line1 + "&#13;" + line2;
System.out.println(rhyme);
//4. Line break for HTML using “&#10&#13;;”
System.out.println("4. Line break for HTML using &#10;&#13;");
rhyme = line1 + "&#10;&#13;" + line2;
System.out.println(rhyme);
//5. Line break for HTML using \n”
System.out.println("5. Line break for HTML using \\n");
rhyme = line1 + "\n" + line2;
System.out.println(rhyme);
}
}

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package com.baeldung.streamoperations;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class JoinerSplitter {
public static String join ( String[] arrayOfString ) {
return Arrays.asList(arrayOfString)
.stream()
.map(x -> x)
.collect(Collectors.joining(","));
}
public static String joinWithPrefixPostFix ( String[] arrayOfString ) {
return Arrays.asList(arrayOfString)
.stream()
.map(x -> x)
.collect(Collectors.joining(",","[","]"));
}
public static List<String> split ( String str ) {
return Stream.of(str.split(","))
.map (elem -> new String(elem))
.collect(Collectors.toList());
}
public static List<Character> splitToListOfChar ( String str ) {
return str.chars()
.mapToObj(item -> (char) item)
.collect(Collectors.toList());
}
public static Map<String, String> arrayToMap(String[] arrayOfString) {
return Arrays.asList(arrayOfString)
.stream()
.map(str -> str.split(":"))
.collect(Collectors.<String[], String, String>toMap(str -> str[0], str -> str[1]));
}
}

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package com.baeldung.substringsearch;
import org.apache.commons.lang3.StringUtils;
import org.openjdk.jmh.annotations.*;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
/**
* Based on https://github.com/tedyoung/indexof-contains-benchmark
*/
@Fork(5)
@State(Scope.Benchmark)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public class SubstringSearchPerformanceComparison {
private String message;
private Pattern pattern;
public static void main(String[] args) throws Exception {
org.openjdk.jmh.Main.main(args);
}
@Setup
public void setup() {
message = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum";
pattern = Pattern.compile("(?<!\\S)" + "eiusmod" + "(?!\\S)");
}
@Benchmark
public int indexOf() {
return message.indexOf("eiusmod");
}
@Benchmark
public boolean contains() {
return message.contains("eiusmod");
}
@Benchmark
public boolean containsStringUtilsIgnoreCase() {
return StringUtils.containsIgnoreCase(message, "eiusmod");
}
@Benchmark
public boolean searchWithPattern() {
return pattern.matcher(message).find();
}
}

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package com.baeldung.tostring;
public class Customer {
private String firstName;
private String lastName;
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}

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package com.baeldung.tostring;
import java.util.Arrays;
public class CustomerArrayToString extends Customer {
private Order[] orders;
public Order[] getOrders() {
return orders;
}
public void setOrders(Order[] orders) {
this.orders = orders;
}
@Override
public String toString() {
return "Customer [orders=" + Arrays.toString(orders) + ", getFirstName()=" + getFirstName() + ", getLastName()=" + getLastName() + "]";
}
}

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package com.baeldung.tostring;
public class CustomerComplexObjectToString extends Customer {
private Order order;
public Order getOrder() {
return order;
}
public void setOrder(Order order) {
this.order = order;
}
@Override
public String toString() {
return "Customer [order=" + order + ", getFirstName()=" + getFirstName() + ", getLastName()=" + getLastName() + "]";
}
}

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package com.baeldung.tostring;
public class CustomerPrimitiveToString extends Customer {
private long balance;
public long getBalance() {
return balance;
}
public void setBalance(long balance) {
this.balance = balance;
}
@Override
public String toString() {
return "Customer [balance=" + balance + ", getFirstName()=" + getFirstName() + ", getLastName()=" + getLastName() + "]";
}
}

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package com.baeldung.tostring;
import java.util.List;
import org.apache.commons.lang3.builder.ReflectionToStringBuilder;
public class CustomerReflectionToString extends Customer {
private Integer score;
private List<String> orders;
private StringBuffer fullname;
public Integer getScore() {
return score;
}
public void setScore(Integer score) {
this.score = score;
}
public List<String> getOrders() {
return orders;
}
public void setOrders(List<String> orders) {
this.orders = orders;
}
public StringBuffer getFullname() {
return fullname;
}
public void setFullname(StringBuffer fullname) {
this.fullname = fullname;
}
@Override
public String toString() {
return ReflectionToStringBuilder.toString(this);
}
}

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package com.baeldung.tostring;
import java.util.List;
public class CustomerWrapperCollectionToString extends Customer {
private Integer score;
private List<String> orders;
private StringBuffer fullname;
public Integer getScore() {
return score;
}
public void setScore(Integer score) {
this.score = score;
}
public List<String> getOrders() {
return orders;
}
public void setOrders(List<String> orders) {
this.orders = orders;
}
public StringBuffer getFullname() {
return fullname;
}
public void setFullname(StringBuffer fullname) {
this.fullname = fullname;
}
@Override
public String toString() {
return "Customer [score=" + score + ", orders=" + orders + ", fullname=" + fullname + ", getFirstName()=" + getFirstName() + ", getLastName()=" + getLastName() + "]";
}
}

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package com.baeldung.tostring;
public class Order {
private String orderId;
private String desc;
private long value;
private String status;
public String getOrderId() {
return orderId;
}
public void setOrderId(String orderId) {
this.orderId = orderId;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
public long getValue() {
return value;
}
public void setValue(long value) {
this.value = value;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
@Override
public String toString() {
return "Order [orderId=" + orderId + ", desc=" + desc + ", value=" + value + "]";
}
}

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# Root logger option
log4j.rootLogger=DEBUG, stdout
# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

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package com.baeldung.base64encodinganddecoding;
import org.apache.commons.codec.binary.Base64;
import org.junit.Test;
import java.io.UnsupportedEncodingException;
import static org.junit.Assert.*;
public class ApacheCommonsEncodeDecodeUnitTest {
// tests
@Test
public void whenStringIsEncoded() throws UnsupportedEncodingException {
final String originalInput = "test input";
final Base64 base64 = new Base64();
final String encodedString = new String(base64.encode(originalInput.getBytes()));
assertNotNull(encodedString);
assertNotEquals(originalInput, encodedString);
}
@Test
public void whenStringIsEncoded_thenStringCanBeDecoded() throws UnsupportedEncodingException {
final String originalInput = "test input";
final Base64 base64 = new Base64();
final String encodedString = new String(base64.encode(originalInput.getBytes()));
final String decodedString = new String(base64.decode(encodedString.getBytes()));
assertNotNull(decodedString);
assertEquals(originalInput, decodedString);
}
@Test
public void whenStringIsEncodedUsingStaticMethod() throws UnsupportedEncodingException {
final String originalInput = "test input";
final String encodedString = new String(Base64.encodeBase64(originalInput.getBytes()));
assertNotNull(encodedString);
assertNotEquals(originalInput, encodedString);
}
@Test
public void whenStringIsEncodedUsingStaticMethod_thenStringCanBeDecodedUsingStaticMethod() throws UnsupportedEncodingException {
final String originalInput = "test input";
final String encodedString = new String(Base64.encodeBase64(originalInput.getBytes()));
final String decodedString = new String(Base64.decodeBase64(encodedString.getBytes()));
assertNotNull(decodedString);
assertEquals(originalInput, decodedString);
}
}

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package com.baeldung.base64encodinganddecoding;
import org.junit.Test;
import java.io.UnsupportedEncodingException;
import java.util.Base64;
import java.util.UUID;
import static org.junit.Assert.*;
public class Java8EncodeDecodeUnitTest {
// tests
@Test
public void whenStringIsEncoded_thenOk() throws UnsupportedEncodingException {
final String originalInput = "test input";
final String encodedString = Base64.getEncoder().encodeToString(originalInput.getBytes());
assertNotNull(encodedString);
assertNotEquals(originalInput, encodedString);
}
@Test
public void whenStringIsEncoded_thenStringCanBeDecoded() throws UnsupportedEncodingException {
final String originalInput = "test input";
final String encodedString = Base64.getEncoder().encodeToString(originalInput.getBytes());
final byte[] decodedBytes = Base64.getDecoder().decode(encodedString);
final String decodedString = new String(decodedBytes);
assertNotNull(decodedString);
assertEquals(originalInput, decodedString);
}
@Test
public void whenStringIsEncodedWithoutPadding_thenOk() throws UnsupportedEncodingException {
final String originalInput = "test input";
final String encodedString = Base64.getEncoder().withoutPadding().encodeToString(originalInput.getBytes());
assertNotNull(encodedString);
assertNotEquals(originalInput, encodedString);
}
@Test
public void whenStringIsEncodedWithoutPadding_thenStringCanBeDecoded() throws UnsupportedEncodingException {
final String originalInput = "test input";
final String encodedString = Base64.getEncoder().withoutPadding().encodeToString(originalInput.getBytes());
final byte[] decodedBytes = Base64.getDecoder().decode(encodedString);
final String decodedString = new String(decodedBytes);
assertNotNull(decodedString);
assertEquals(originalInput, decodedString);
}
@Test
public void whenUrlIsEncoded_thenOk() throws UnsupportedEncodingException {
final String originalUrl = "https://www.google.co.nz/?gfe_rd=cr&ei=dzbFVf&gws_rd=ssl#q=java";
final String encodedUrl = Base64.getUrlEncoder().encodeToString(originalUrl.getBytes());
assertNotNull(encodedUrl);
assertNotEquals(originalUrl, encodedUrl);
}
@Test
public void whenUrlIsEncoded_thenURLCanBeDecoded() throws UnsupportedEncodingException {
final String originalUrl = "https://www.google.co.nz/?gfe_rd=cr&ei=dzbFVf&gws_rd=ssl#q=java";
final String encodedUrl = Base64.getUrlEncoder().encodeToString(originalUrl.getBytes());
final byte[] decodedBytes = Base64.getUrlDecoder().decode(encodedUrl.getBytes());
final String decodedUrl = new String(decodedBytes);
assertNotNull(decodedUrl);
assertEquals(originalUrl, decodedUrl);
}
@Test
public void whenMimeIsEncoded_thenOk() throws UnsupportedEncodingException {
final StringBuilder buffer = getMimeBuffer();
final byte[] forEncode = buffer.toString().getBytes();
final String encodedMime = Base64.getMimeEncoder().encodeToString(forEncode);
assertNotNull(encodedMime);
}
@Test
public void whenMimeIsEncoded_thenItCanBeDecoded() throws UnsupportedEncodingException {
final StringBuilder buffer = getMimeBuffer();
final byte[] forEncode = buffer.toString().getBytes();
final String encodedMime = Base64.getMimeEncoder().encodeToString(forEncode);
final byte[] decodedBytes = Base64.getMimeDecoder().decode(encodedMime);
final String decodedMime = new String(decodedBytes);
assertNotNull(decodedMime);
}
//
private static StringBuilder getMimeBuffer() {
final StringBuilder buffer = new StringBuilder();
for (int count = 0; count < 10; ++count) {
buffer.append(UUID.randomUUID().toString());
}
return buffer;
}
}

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package com.baeldung.base64encodinganddecoding;
import org.junit.Test;
import javax.xml.bind.DatatypeConverter;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Base64;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
public class StringToByteArrayUnitTest {
@Test
public void whenConvertStringToByteArrayUsingStringClass_thenOk() {
final String originalInput = "test input";
byte[] result = originalInput.getBytes();
System.out.println(Arrays.toString(result));
assertEquals(originalInput.length(), result.length);
}
@Test
public void givenCharset_whenConvertStringToByteArrayUsingStringClass_thenOk() throws UnsupportedEncodingException {
final String originalInput = "test input";
byte[] result = originalInput.getBytes(StandardCharsets.UTF_16);
System.out.println(Arrays.toString(result));
assertTrue(originalInput.length() < result.length);
}
@Test
public void whenConvertStringToByteArrayUsingBase64Decoder_thenOk() {
final String originalInput = "dGVzdCBpbnB1dA==";
byte[] result = Base64.getDecoder().decode(originalInput);
assertEquals("test input", new String(result));
}
@Test
public void whenConvertStringToByteArrayUsingDatatypeConverter_thenOk() {
final String originalInput = "dGVzdCBpbnB1dA==";
byte[] result = DatatypeConverter.parseBase64Binary(originalInput);
assertEquals("test input", new String(result));
}
@Test
public void whenConvertStringToByteArray_thenOk(){
String originalInput = "7465737420696E707574";
byte[] result = DatatypeConverter.parseHexBinary(originalInput);
System.out.println(Arrays.toString(result));
assertEquals("test input", new String(result));
}
}

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package com.baeldung.isnumeric;
import static org.assertj.core.api.Assertions.assertThat;
import org.junit.Test;
public class CoreJavaIsNumericUnitTest {
public static boolean isNumeric(String strNum) {
try {
double d = Double.parseDouble(strNum);
} catch (NumberFormatException | NullPointerException nfe) {
return false;
}
return true;
}
@Test
public void whenUsingCoreJava_thenTrue() {
// Valid Numbers
assertThat(isNumeric("22")).isTrue();
assertThat(isNumeric("5.05")).isTrue();
assertThat(isNumeric("-200")).isTrue();
assertThat(isNumeric("10.0d")).isTrue();
assertThat(isNumeric(" 22 ")).isTrue();
// Invalid Numbers
assertThat(isNumeric(null)).isFalse();
assertThat(isNumeric("")).isFalse();
assertThat(isNumeric("abc")).isFalse();
}
}

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package com.baeldung.isnumeric;
import static org.assertj.core.api.Assertions.assertThat;
import org.apache.commons.lang3.math.NumberUtils;
import org.junit.Test;
public class NumberUtilsIsCreatableUnitTest {
@Test
public void givenApacheCommons_whenUsingIsParsable_thenTrue() {
// Valid Numbers
assertThat(NumberUtils.isCreatable("22")).isTrue();
assertThat(NumberUtils.isCreatable("5.05")).isTrue();
assertThat(NumberUtils.isCreatable("-200")).isTrue();
assertThat(NumberUtils.isCreatable("10.0d")).isTrue();
assertThat(NumberUtils.isCreatable("1000L")).isTrue();
assertThat(NumberUtils.isCreatable("0xFF")).isTrue();
assertThat(NumberUtils.isCreatable("07")).isTrue();
assertThat(NumberUtils.isCreatable("2.99e+8")).isTrue();
// Invalid Numbers
assertThat(NumberUtils.isCreatable(null)).isFalse();
assertThat(NumberUtils.isCreatable("")).isFalse();
assertThat(NumberUtils.isCreatable("abc")).isFalse();
assertThat(NumberUtils.isCreatable(" 22 ")).isFalse();
assertThat(NumberUtils.isCreatable("09")).isFalse();
}
}

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package com.baeldung.isnumeric;
import static org.assertj.core.api.Assertions.assertThat;
import org.apache.commons.lang3.math.NumberUtils;
import org.junit.Test;
public class NumberUtilsIsParsableUnitTest {
@Test
public void givenApacheCommons_whenUsingIsParsable_thenTrue() {
// Valid Numbers
assertThat(NumberUtils.isParsable("22")).isTrue();
assertThat(NumberUtils.isParsable("-23")).isTrue();
assertThat(NumberUtils.isParsable("2.2")).isTrue();
assertThat(NumberUtils.isParsable("09")).isTrue();
// Invalid Numbers
assertThat(NumberUtils.isParsable(null)).isFalse();
assertThat(NumberUtils.isParsable("")).isFalse();
assertThat(NumberUtils.isParsable("6.2f")).isFalse();
assertThat(NumberUtils.isParsable("9.8d")).isFalse();
assertThat(NumberUtils.isParsable("22L")).isFalse();
assertThat(NumberUtils.isParsable("0xFF")).isFalse();
assertThat(NumberUtils.isParsable("2.99e+8")).isFalse();
}
}

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package com.baeldung.isnumeric;
import static org.assertj.core.api.Assertions.assertThat;
import org.junit.Test;
public class RegularExpressionsUnitTest {
public static boolean isNumeric(String strNum) {
return strNum.matches("-?\\d+(\\.\\d+)?");
}
@Test
public void whenUsingRegularExpressions_thenTrue() {
// Valid Numbers
assertThat(isNumeric("22")).isTrue();
assertThat(isNumeric("5.05")).isTrue();
assertThat(isNumeric("-200")).isTrue();
// Invalid Numbers
assertThat(isNumeric("abc")).isFalse();
}
}

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package com.baeldung.isnumeric;
import static org.assertj.core.api.Assertions.assertThat;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
public class StringUtilsIsNumericSpaceUnitTest {
@Test
public void givenApacheCommons_whenUsingIsNumericSpace_thenTrue() {
// Valid Numbers
assertThat(StringUtils.isNumericSpace("123")).isTrue();
assertThat(StringUtils.isNumericSpace("١٢٣")).isTrue();
assertThat(StringUtils.isNumericSpace("")).isTrue();
assertThat(StringUtils.isNumericSpace(" ")).isTrue();
assertThat(StringUtils.isNumericSpace("12 3")).isTrue();
// Invalid Numbers
assertThat(StringUtils.isNumericSpace(null)).isFalse();
assertThat(StringUtils.isNumericSpace("ab2c")).isFalse();
assertThat(StringUtils.isNumericSpace("12.3")).isFalse();
assertThat(StringUtils.isNumericSpace("-123")).isFalse();
}
}

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package com.baeldung.isnumeric;
import static org.assertj.core.api.Assertions.assertThat;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
public class StringUtilsIsNumericUnitTest {
@Test
public void givenApacheCommons_whenUsingIsNumeric_thenTrue() {
// Valid Numbers
assertThat(StringUtils.isNumeric("123")).isTrue();
assertThat(StringUtils.isNumeric("١٢٣")).isTrue();
assertThat(StringUtils.isNumeric("१२३")).isTrue();
// Invalid Numbers
assertThat(StringUtils.isNumeric(null)).isFalse();
assertThat(StringUtils.isNumeric("")).isFalse();
assertThat(StringUtils.isNumeric(" ")).isFalse();
assertThat(StringUtils.isNumeric("12 3")).isFalse();
assertThat(StringUtils.isNumeric("ab2c")).isFalse();
assertThat(StringUtils.isNumeric("12.3")).isFalse();
assertThat(StringUtils.isNumeric("-123")).isFalse();
}
}

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package com.baeldung.split;
import static org.assertj.core.api.Assertions.assertThat;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.lang3.StringUtils;
import org.junit.jupiter.api.Test;
import com.google.common.base.Splitter;
public class SplitUnitTest {
@Test
public void givenString_whenSplit_thenReturnsArray_through_JavaLangString() {
assertThat("peter,james,thomas".split(",")).containsExactly("peter", "james", "thomas");
assertThat("car jeep scooter".split(" ")).containsExactly("car", "jeep", "scooter");
assertThat("1-120-232323".split("-")).containsExactly("1", "120", "232323");
assertThat("192.168.1.178".split("\\.")).containsExactly("192", "168", "1", "178");
assertThat("b a, e, l.d u, n g".split("\\s+|,\\s*|\\.\\s*")).containsExactly("b", "a", "e", "l", "d", "u", "n", "g");
}
@Test
public void givenString_whenSplit_thenReturnsArray_through_StringUtils() {
StringUtils.split("car jeep scooter");
assertThat(StringUtils.split("car jeep scooter")).containsExactly("car", "jeep", "scooter");
assertThat(StringUtils.split("car jeep scooter")).containsExactly("car", "jeep", "scooter");
assertThat(StringUtils.split("car:jeep:scooter", ":")).containsExactly("car", "jeep", "scooter");
assertThat(StringUtils.split("car.jeep.scooter", ".")).containsExactly("car", "jeep", "scooter");
}
@Test
public void givenString_whenSplit_thenReturnsList_Splitter() {
// given
List<String> resultList = Splitter.on(',')
.trimResults()
.omitEmptyStrings()
.splitToList("car,jeep,, scooter");
assertThat(resultList).containsExactly("car", "jeep", "scooter");
}
@Test
public void givenStringContainsSpaces_whenSplitAndTrim_thenReturnsArray_using_Regex() {
assertThat(" car , jeep, scooter ".trim()
.split("\\s*,\\s*")).containsExactly("car", "jeep", "scooter");
}
@Test
public void givenStringContainsSpaces_whenSplitAndTrim_thenReturnsArray_using_java_8() {
assertThat(Arrays.stream(" car , jeep, scooter ".split(","))
.map(String::trim)
.toArray(String[]::new)).containsExactly("car", "jeep", "scooter");
}
}

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package com.baeldung.streamoperations;
import org.junit.Test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import static org.junit.Assert.assertEquals;
public class JoinerSplitterUnitTest {
@Test
public void provided_array_convert_to_stream_and_convert_to_string() {
String[] programming_languages = {"java", "python", "nodejs", "ruby"};
String expectation = "java,python,nodejs,ruby";
String result = JoinerSplitter.join(programming_languages);
assertEquals(result, expectation);
}
@Test
public void givenArray_transformedToStream_convertToPrefixPostfixString() {
String[] programming_languages = {"java", "python",
"nodejs", "ruby"};
String expectation = "[java,python,nodejs,ruby]";
String result = JoinerSplitter.joinWithPrefixPostFix(programming_languages);
assertEquals(result, expectation);
}
@Test
public void givenString_transformedToStream_convertToList() {
String programming_languages = "java,python,nodejs,ruby";
List<String> expectation = new ArrayList<String>();
expectation.add("java");
expectation.add("python");
expectation.add("nodejs");
expectation.add("ruby");
List<String> result = JoinerSplitter.split(programming_languages);
assertEquals(result, expectation);
}
@Test
public void givenString_transformedToStream_convertToListOfChar() {
String programming_languages = "java,python,nodejs,ruby";
List<Character> expectation = new ArrayList<Character>();
char[] charArray = programming_languages.toCharArray();
for (char c : charArray) {
expectation.add(c);
}
List<Character> result = JoinerSplitter.splitToListOfChar(programming_languages);
assertEquals(result, expectation);
}
@Test
public void givenStringArray_transformedToStream_convertToMap() {
String[] programming_languages = new String[] {"language:java","os:linux","editor:emacs"};
Map<String,String> expectation=new HashMap<>();
expectation.put("language", "java");
expectation.put("os", "linux");
expectation.put("editor", "emacs");
Map<String, String> result = JoinerSplitter.arrayToMap(programming_languages);
assertEquals(result, expectation);
}
}

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package com.baeldung.stringcomparison;
import static org.assertj.core.api.Assertions.assertThat;
import java.util.Objects;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
public class StringComparisonUnitTest {
@Test
public void whenUsingComparisonOperator_ThenComparingStrings() {
String string1 = "using comparison operator";
String string2 = "using comparison operator";
String string3 = new String("using comparison operator");
assertThat(string1 == string2).isTrue();
assertThat(string1 == string3).isFalse();
}
@Test
public void whenUsingEqualsMethod_ThenComparingStrings() {
String string1 = "using equals method";
String string2 = "using equals method";
String string3 = "using EQUALS method";
String string4 = new String("using equals method");
assertThat(string1.equals(string2)).isTrue();
assertThat(string1.equals(string4)).isTrue();
assertThat(string1.equals(null)).isFalse();
assertThat(string1.equals(string3)).isFalse();
}
@Test
public void whenUsingEqualsIgnoreCase_ThenComparingStrings() {
String string1 = "using equals ignore case";
String string2 = "USING EQUALS IGNORE CASE";
assertThat(string1.equalsIgnoreCase(string2)).isTrue();
}
@Test
public void whenUsingCompareTo_ThenComparingStrings() {
String author = "author";
String book = "book";
String duplicateBook = "book";
assertThat(author.compareTo(book)).isEqualTo(-1);
assertThat(book.compareTo(author)).isEqualTo(1);
assertThat(duplicateBook.compareTo(book)).isEqualTo(0);
}
@Test
public void whenUsingCompareToIgnoreCase_ThenComparingStrings() {
String author = "Author";
String book = "book";
String duplicateBook = "BOOK";
assertThat(author.compareToIgnoreCase(book)).isEqualTo(-1);
assertThat(book.compareToIgnoreCase(author)).isEqualTo(1);
assertThat(duplicateBook.compareToIgnoreCase(book)).isEqualTo(0);
}
@Test
public void whenUsingObjectsEqualsMethod_ThenComparingStrings() {
String string1 = "using objects equals";
String string2 = "using objects equals";
String string3 = new String("using objects equals");
assertThat(Objects.equals(string1, string2)).isTrue();
assertThat(Objects.equals(string1, string3)).isTrue();
assertThat(Objects.equals(null, null)).isTrue();
assertThat(Objects.equals(null, string1)).isFalse();
}
@Test
public void whenUsingEqualsOfApacheCommons_ThenComparingStrings() {
assertThat(StringUtils.equals(null, null)).isTrue();
assertThat(StringUtils.equals(null, "equals method")).isFalse();
assertThat(StringUtils.equals("equals method", "equals method")).isTrue();
assertThat(StringUtils.equals("equals method", "EQUALS METHOD")).isFalse();
}
@Test
public void whenUsingEqualsIgnoreCaseOfApacheCommons_ThenComparingStrings() {
assertThat(StringUtils.equalsIgnoreCase(null, null)).isTrue();
assertThat(StringUtils.equalsIgnoreCase(null, "equals method")).isFalse();
assertThat(StringUtils.equalsIgnoreCase("equals method", "equals method")).isTrue();
assertThat(StringUtils.equalsIgnoreCase("equals method", "EQUALS METHOD")).isTrue();
}
@Test
public void whenUsingEqualsAnyOf_ThenComparingStrings() {
assertThat(StringUtils.equalsAny(null, null, null)).isTrue();
assertThat(StringUtils.equalsAny("equals any", "equals any", "any")).isTrue();
assertThat(StringUtils.equalsAny("equals any", null, "equals any")).isTrue();
assertThat(StringUtils.equalsAny(null, "equals", "any")).isFalse();
assertThat(StringUtils.equalsAny("equals any", "EQUALS ANY", "ANY")).isFalse();
}
@Test
public void whenUsingEqualsAnyIgnoreCase_ThenComparingStrings() {
assertThat(StringUtils.equalsAnyIgnoreCase(null, null, null)).isTrue();
assertThat(StringUtils.equalsAnyIgnoreCase("equals any", "equals any", "any")).isTrue();
assertThat(StringUtils.equalsAnyIgnoreCase("equals any", null, "equals any")).isTrue();
assertThat(StringUtils.equalsAnyIgnoreCase(null, "equals", "any")).isFalse();
assertThat(StringUtils.equalsAnyIgnoreCase("equals any ignore case", "EQUALS ANY IGNORE CASE", "any")).isTrue();
}
@Test
public void whenUsingCompare_thenComparingStringsWithNulls() {
assertThat(StringUtils.compare(null, null)).isEqualTo(0);
assertThat(StringUtils.compare(null, "abc")).isEqualTo(-1);
assertThat(StringUtils.compare("abc", "bbc")).isEqualTo(-1);
assertThat(StringUtils.compare("bbc", "abc")).isEqualTo(1);
assertThat(StringUtils.compare("abc", "abc")).isEqualTo(0);
}
@Test
public void whenUsingCompareIgnoreCase_ThenComparingStringsWithNulls() {
assertThat(StringUtils.compareIgnoreCase(null, null)).isEqualTo(0);
assertThat(StringUtils.compareIgnoreCase(null, "abc")).isEqualTo(-1);
assertThat(StringUtils.compareIgnoreCase("Abc", "bbc")).isEqualTo(-1);
assertThat(StringUtils.compareIgnoreCase("bbc", "ABC")).isEqualTo(1);
assertThat(StringUtils.compareIgnoreCase("abc", "ABC")).isEqualTo(0);
}
@Test
public void whenUsingCompareWithNullIsLessOption_ThenComparingStrings() {
assertThat(StringUtils.compare(null, "abc", true)).isEqualTo(-1);
assertThat(StringUtils.compare(null, "abc", false)).isEqualTo(1);
}
}

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package com.baeldung.substring;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang3.StringUtils;
import org.junit.Assert;
import org.junit.Test;
public class SubstringUnitTest {
String text = "Julia Evans was born on 25-09-1984. She is currently living in the USA (United States of America).";
@Test
public void givenAString_whenUsedStringUtils_ShouldReturnProperSubstring() {
Assert.assertEquals("United States of America", StringUtils.substringBetween(text, "(", ")"));
Assert.assertEquals("the USA (United States of America).", StringUtils.substringAfter(text, "living in "));
Assert.assertEquals("Julia Evans", StringUtils.substringBefore(text, " was born"));
}
@Test
public void givenAString_whenUsedScanner_ShouldReturnProperSubstring() {
try (Scanner scanner = new Scanner(text)) {
scanner.useDelimiter("\\.");
Assert.assertEquals("Julia Evans was born on 25-09-1984", scanner.next());
}
}
@Test
public void givenAString_whenUsedSplit_ShouldReturnProperSubstring() {
String[] sentences = text.split("\\.");
Assert.assertEquals("Julia Evans was born on 25-09-1984", sentences[0]);
}
@Test
public void givenAString_whenUsedRegex_ShouldReturnProperSubstring() {
Pattern pattern = Pattern.compile("\\d{2}\\-\\d{2}-\\d{4}");
Matcher matcher = pattern.matcher(text);
if (matcher.find()) {
Assert.assertEquals("25-09-1984", matcher.group());
}
}
@Test
public void givenAString_whenUsedSubSequence_ShouldReturnProperSubstring() {
Assert.assertEquals("USA (United States of America)", text.subSequence(67, text.length() - 1));
}
@Test
public void givenAString_whenUsedSubstring_ShouldReturnProperSubstring() {
Assert.assertEquals("USA (United States of America).", text.substring(67));
Assert.assertEquals("USA (United States of America)", text.substring(67, text.length() - 1));
}
@Test
public void givenAString_whenUsedSubstringWithIndexOf_ShouldReturnProperSubstring() {
Assert.assertEquals("United States of America", text.substring(text.indexOf('(') + 1, text.indexOf(')')));
}
@Test
public void givenAString_whenUsedSubstringWithLastIndexOf_ShouldReturnProperSubstring() {
Assert.assertEquals("1984", text.substring(text.lastIndexOf('-') + 1, text.indexOf('.')));
}
@Test
public void givenAString_whenUsedSubstringWithIndexOfAString_ShouldReturnProperSubstring() {
Assert.assertEquals("USA (United States of America)", text.substring(text.indexOf("USA"), text.indexOf(')') + 1));
}
}

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package com.baeldung.substringsearch;
import org.apache.commons.lang3.StringUtils;
import org.junit.Assert;
import org.junit.Test;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* BAEL-2832: Different ways to check if a Substring could be found in a String.
*/
public class SubstringSearchUnitTest {
@Test
public void searchSubstringWithIndexOf() {
Assert.assertEquals(9, "Bohemian Rhapsodyan".indexOf("Rhap"));
// indexOf will return -1, because it's case sensitive
Assert.assertEquals(-1, "Bohemian Rhapsodyan".indexOf("rhap"));
// indexOf will return 9, because it's all lowercase
Assert.assertEquals(9, "Bohemian Rhapsodyan".toLowerCase()
.indexOf("rhap"));
// it will return 6, because it's the first occurrence. Sorry Queen for being blasphemic
Assert.assertEquals(6, "Bohemian Rhapsodyan".indexOf("an"));
}
@Test
public void searchSubstringWithContains() {
Assert.assertTrue("Hey Ho, let's go".contains("Hey"));
// contains will return false, because it's case sensitive
Assert.assertFalse("Hey Ho, let's go".contains("hey"));
// contains will return true, because it's all lowercase
Assert.assertTrue("Hey Ho, let's go".toLowerCase().contains("hey"));
// contains will return false, because 'jey' can't be found
Assert.assertFalse("Hey Ho, let's go".contains("jey"));
}
@Test
public void searchSubstringWithStringUtils() {
Assert.assertTrue(StringUtils.containsIgnoreCase("Runaway train", "train"));
// it will also be true, because ignores case ;)
Assert.assertTrue(StringUtils.containsIgnoreCase("Runaway train", "Train"));
}
@Test
public void searchUsingPattern() {
// We create the Pattern first
Pattern pattern = Pattern.compile("(?<!\\S)" + "road" + "(?!\\S)");
// We need to create the Matcher after
Matcher matcher = pattern.matcher("Hit the road Jack");
// find will return true when the first match is found
Assert.assertTrue(matcher.find());
// We will create a different matcher with a different text
matcher = pattern.matcher("and don't you come back no more");
// find will return false, because 'road' can't be find as a substring
Assert.assertFalse(matcher.find());
}
}

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package com.baeldung.tostring;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
public class CustomerArrayToStringUnitTest {
private static final String CUSTOMER_ARRAY_TO_STRING = "Customer [orders=[Order [orderId=A1111, desc=Game, value=0]], getFirstName()=Rajesh, getLastName()=Bhojwani]";
@Test
public void givenArray_whenToString_thenCustomerDetails() {
CustomerArrayToString customer = new CustomerArrayToString();
customer.setFirstName("Rajesh");
customer.setLastName("Bhojwani");
Order[] orders = new Order[1];
orders[0] = new Order();
orders[0].setOrderId("A1111");
orders[0].setDesc("Game");
orders[0].setStatus("In-Shiping");
customer.setOrders(orders);
assertEquals(CUSTOMER_ARRAY_TO_STRING, customer.toString());
}
}

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package com.baeldung.tostring;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
public class CustomerComplexObjectToStringUnitTest {
private static final String CUSTOMER_COMPLEX_TO_STRING = "Customer [order=Order [orderId=A1111, desc=Game, value=0], getFirstName()=Rajesh, getLastName()=Bhojwani]";
@Test
public void givenComplex_whenToString_thenCustomerDetails() {
CustomerComplexObjectToString customer = new CustomerComplexObjectToString();
customer.setFirstName("Rajesh");
customer.setLastName("Bhojwani");
Order order = new Order();
order.setOrderId("A1111");
order.setDesc("Game");
order.setStatus("In-Shiping");
customer.setOrder(order);
assertEquals(CUSTOMER_COMPLEX_TO_STRING, customer.toString());
}
}

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package com.baeldung.tostring;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
public class CustomerPrimitiveToStringUnitTest {
private static final String CUSTOMER_PRIMITIVE_TO_STRING = "Customer [balance=110, getFirstName()=Rajesh, getLastName()=Bhojwani]";
@Test
public void givenPrimitive_whenToString_thenCustomerDetails() {
CustomerPrimitiveToString customer = new CustomerPrimitiveToString();
customer.setFirstName("Rajesh");
customer.setLastName("Bhojwani");
customer.setBalance(110);
assertEquals(CUSTOMER_PRIMITIVE_TO_STRING, customer.toString());
}
}

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package com.baeldung.tostring;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.util.ArrayList;
import java.util.List;
import org.junit.jupiter.api.Test;
public class CustomerWrapperCollectionToStringUnitTest {
private static final String CUSTOMER_WRAPPER_COLLECTION_TO_STRING = "Customer [score=8, orders=[Book, Pen], fullname=Bhojwani, Rajesh, getFirstName()=Rajesh, getLastName()=Bhojwani]";
@Test
public void givenWrapperCollectionStrBuffer_whenToString_thenCustomerDetails() {
CustomerWrapperCollectionToString customer = new CustomerWrapperCollectionToString();
customer.setFirstName("Rajesh");
customer.setLastName("Bhojwani");
customer.setScore(8);
List<String> orders = new ArrayList<String>();
orders.add("Book");
orders.add("Pen");
customer.setOrders(orders);
StringBuffer fullname = new StringBuffer();
fullname.append(customer.getLastName() + ", " + customer.getFirstName());
customer.setFullname(fullname);
assertEquals(CUSTOMER_WRAPPER_COLLECTION_TO_STRING, customer.toString());
}
}

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@@ -31,7 +31,7 @@
- [Abstract Classes in Java](https://www.baeldung.com/java-abstract-class)
- [Guide to Character Encoding](https://www.baeldung.com/java-char-encoding)
- [Graphs in Java](https://www.baeldung.com/java-graphs)
- [Console I/O in Java](http://www.baeldung.com/java-console-input-output)
- [Read and Write User Input in Java](http://www.baeldung.com/java-console-input-output)
- [Formatting with printf() in Java](https://www.baeldung.com/java-printstream-printf)
- [Retrieve Fields from a Java Class Using Reflection](https://www.baeldung.com/java-reflection-class-fields)
- [Introduction to Basic Syntax in Java](https://www.baeldung.com/java-syntax)