Merge branch 'master' of https://github.com/vikasrajput6035/tutorials into BAEL-4936

core-java-modules/core-java-10/README.md

@@ -5,7 +5,10 @@ This module contains articles about Java 10 core features
 ### Relevant Articles: 
 
 - [Java 10 LocalVariable Type-Inference](http://www.baeldung.com/java-10-local-variable-type-inference)
-- [Guide to Java 10](http://www.baeldung.com/java-10-overview)
+- [New Features in Java 10](https://www.baeldung.com/java-10-overview)
 - [Copy a List to Another List in Java](http://www.baeldung.com/java-copy-list-to-another)
 - [Deep Dive Into the New Java JIT Compiler – Graal](https://www.baeldung.com/graal-java-jit-compiler)
 - [Copying Sets in Java](https://www.baeldung.com/java-copy-sets)
+- [Converting between a List and a Set in Java](https://www.baeldung.com/convert-list-to-set-and-set-to-list)
+- [Java IndexOutOfBoundsException “Source Does Not Fit in Dest”](https://www.baeldung.com/java-indexoutofboundsexception)
+- [Collect a Java Stream to an Immutable Collection](https://www.baeldung.com/java-stream-immutable-collection)

core-java-modules/core-java-10/pom.xml

@@ -1,22 +1,29 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project
-    xmlns="http://maven.apache.org/POM/4.0.0"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+        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-10</artifactId>
     <version>0.1.0-SNAPSHOT</version>
     <name>core-java-10</name>
     <packaging>jar</packaging>
-    <url>http://maven.apache.org</url>
 
     <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../../</relativePath>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../</relativePath>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-collections4</artifactId>
+            <version>${commons-collections4.version}</version>
+        </dependency>
+    </dependencies>
+
     <build>
         <plugins>
             <plugin>
@@ -34,6 +41,7 @@
     <properties>
         <maven.compiler.source.version>10</maven.compiler.source.version>
         <maven.compiler.target.version>10</maven.compiler.target.version>
+        <commons-collections4.version>4.1</commons-collections4.version>
     </properties>
 
 </project>

core-java-modules/core-java-10/src/test/java/com/baeldung/AppUnitTest.java

@@ -7,7 +7,7 @@ import junit.framework.TestSuite;
 /**
  * Unit test for simple App.
  */
-public class AppTest 
+public class AppUnitTest
     extends TestCase
 {
     /**
@@ -15,7 +15,7 @@ public class AppTest
      *
      * @param testName name of the test case
      */
-    public AppTest( String testName )
+    public AppUnitTest(String testName )
     {
         super( testName );
     }
@@ -25,7 +25,7 @@ public class AppTest
      */
     public static Test suite()
     {
-        return new TestSuite( AppTest.class );
+        return new TestSuite( AppUnitTest.class );
     }
 
     /**

core-java-modules/core-java-10/src/test/java/com/baeldung/java10/collections/conversion/ListSetConversionUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.java10.collections.conversion;
+
+import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
+import org.apache.commons.collections4.CollectionUtils;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class ListSetConversionUnitTest {
+
+    // Set -> List; List -> Set
+
+    @Test
+    public final void givenUsingCoreJava_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = new ArrayList<>(sourceSet);
+    }
+
+    @Test
+    public final void givenUsingCoreJava_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = new HashSet<>(sourceList);
+    }
+
+    @Test
+    public void givenUsingJava10_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = List.copyOf(sourceSet);
+    }
+
+    @Test
+    public void givenUsingJava10_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = Set.copyOf(sourceList);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+        final List<Integer> targetList = Lists.newArrayList(sourceSet);
+    }
+
+    @Test
+    public final void givenUsingGuava_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+        final Set<Integer> targetSet = Sets.newHashSet(sourceList);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenListConvertedToSet_thenCorrect() {
+        final List<Integer> sourceList = Lists.newArrayList(0, 1, 2, 3, 4, 5);
+
+        final Set<Integer> targetSet = new HashSet<>(6);
+        CollectionUtils.addAll(targetSet, sourceList);
+    }
+
+    @Test
+    public final void givenUsingCommonsCollections_whenSetConvertedToList_thenCorrect() {
+        final Set<Integer> sourceSet = Sets.newHashSet(0, 1, 2, 3, 4, 5);
+
+        final List<Integer> targetList = new ArrayList<>(6);
+        CollectionUtils.addAll(targetList, sourceSet);
+    }
+}

core-java-modules/core-java-10/src/test/java/com/baeldung/java10/list/CopyListServiceUnitTest.java

@@ -10,5 +10,6 @@ public class CopyListServiceUnitTest {
     @Test(expected = UnsupportedOperationException.class)
     public void whenModifyCopyOfList_thenThrowsException() {
         List<Integer> copyList = List.copyOf(Arrays.asList(1, 2, 3, 4));
+        copyList.add(4);
     }
 }

core-java-modules/core-java-10/src/test/java/com/baeldung/java10/streams/StreamToImmutableJava10UnitTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.java10.streams;
+
+import static java.util.stream.Collectors.toUnmodifiableList;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Test;
+
+public class StreamToImmutableJava10UnitTest {
+
+    @Test
+    public void whenUsingCollectorsToUnmodifiableList_thenSuccess() {
+        List<String> givenList = Arrays.asList("a", "b", "c");
+        List<String> result = givenList.stream()
+            .collect(toUnmodifiableList());
+
+        System.out.println(result.getClass());
+    }
+}

core-java-modules/core-java-11-2/README.md

@@ -0,0 +1,9 @@
+## Core Java 11
+
+This module contains articles about Java 11 core features
+
+### Relevant articles
+- [Guide to Java 8 Optional](https://www.baeldung.com/java-optional)
+- [Guide to Java Reflection](http://www.baeldung.com/java-reflection)
+- [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors)
+- [New Features in Java 11](https://www.baeldung.com/java-11-new-features)

core-java-modules/core-java-11-2/pom.xml

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project
+        xmlns="http://maven.apache.org/POM/4.0.0"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-java-11-2</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-11-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../..</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mock-server</groupId>
+            <artifactId>mockserver-junit-jupiter</artifactId>
+            <version>${mockserver.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-params</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source.version}</source>
+                    <target>${maven.compiler.target.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <maven.compiler.source.version>11</maven.compiler.source.version>
+        <maven.compiler.target.version>11</maven.compiler.target.version>
+        <guava.version>29.0-jre</guava.version>
+        <junit.jupiter.version>5.7.0</junit.jupiter.version>
+        <assertj.version>3.17.2</assertj.version>
+        <mockserver.version>5.11.1</mockserver.version>
+    </properties>
+
+</project>

core-java-modules/core-java-11-2/src/main/java/com/baeldung/features/MainClass.java

@@ -0,0 +1,17 @@
+package com.baeldung.features;
+
+public class MainClass {
+
+    private static boolean mainPrivateMethod() {
+        return true;
+    }
+
+    public static class NestedClass {
+
+        boolean nestedPublicMethod() {
+            return mainPrivateMethod();
+        }
+
+    }
+
+}

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Animal.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 public abstract class Animal implements Eating {
 

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Bird.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 public class Bird extends Animal {
     private boolean walks;

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/DynamicGreeter.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 import java.lang.annotation.Annotation;
 

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Eating.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 public interface Eating {
     String eats();

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Goat.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 public class Goat extends Animal implements Locomotion {
 

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Greeter.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/GreetingAnnotation.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Field;

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Greetings.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 @Greeter(greet="Good morning")
 public class Greetings {

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Locomotion.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 public interface Locomotion {
     String getLocomotion();

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Operations.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 public class Operations {
 

core-java-modules/core-java-11-2/src/main/java/com/baeldung/reflection/Person.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 public class Person {
     private String name;

core-java-modules/core-java-11-2/src/test/java/com/baeldung/collectors/Java8CollectorsUnitTest.java

@@ -1,18 +1,11 @@
-package com.baeldung.streams.collectors;
+package com.baeldung.collectors;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
 import org.junit.Test;
 
-import java.util.Arrays;
-import java.util.Comparator;
-import java.util.DoubleSummaryStatistics;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.Set;
+import java.util.*;
 import java.util.function.BiConsumer;
 import java.util.function.BinaryOperator;
 import java.util.function.Function;
@@ -20,19 +13,7 @@ import java.util.function.Supplier;
 import java.util.stream.Collector;
 
 import static com.google.common.collect.Sets.newHashSet;
-import static java.util.stream.Collectors.averagingDouble;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.counting;
-import static java.util.stream.Collectors.groupingBy;
-import static java.util.stream.Collectors.joining;
-import static java.util.stream.Collectors.maxBy;
-import static java.util.stream.Collectors.partitioningBy;
-import static java.util.stream.Collectors.summarizingDouble;
-import static java.util.stream.Collectors.summingDouble;
-import static java.util.stream.Collectors.toCollection;
-import static java.util.stream.Collectors.toList;
-import static java.util.stream.Collectors.toMap;
-import static java.util.stream.Collectors.toSet;
+import static java.util.stream.Collectors.*;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
@@ -48,6 +29,14 @@ public class Java8CollectorsUnitTest {
         assertThat(result).containsAll(givenList);
     }
 
+    @Test
+    public void whenCollectingToUnmodifiableList_shouldCollectToUnmodifiableList() {
+        final List<String> result = givenList.stream().collect(toUnmodifiableList());
+
+        assertThatThrownBy(() -> result.add("foo"))
+          .isInstanceOf(UnsupportedOperationException.class);
+    }
+
     @Test
     public void whenCollectingToSet_shouldCollectToSet() throws Exception {
         final Set<String> result = givenList.stream().collect(toSet());
@@ -55,6 +44,14 @@ public class Java8CollectorsUnitTest {
         assertThat(result).containsAll(givenList);
     }
 
+    @Test
+    public void whenCollectingToUnmodifiableSet_shouldCollectToUnmodifiableSet() {
+        final Set<String> result = givenList.stream().collect(toUnmodifiableSet());
+
+        assertThatThrownBy(() -> result.add("foo"))
+          .isInstanceOf(UnsupportedOperationException.class);
+    }
+
     @Test
     public void givenContainsDuplicateElements_whenCollectingToSet_shouldAddDuplicateElementsOnlyOnce() throws Exception {
         final Set<String> result = listWithDuplicates.stream().collect(toSet());
@@ -84,6 +81,15 @@ public class Java8CollectorsUnitTest {
         assertThat(result).containsEntry("a", 1).containsEntry("bb", 2).containsEntry("ccc", 3).containsEntry("dd", 2);
     }
 
+    @Test
+    public void whenCollectingToUnmodifiableMap_shouldCollectToUnmodifiableMap() {
+        final Map<String, Integer> result = givenList.stream()
+          .collect(toUnmodifiableMap(Function.identity(), String::length));
+
+        assertThatThrownBy(() -> result.put("foo", 3))
+                .isInstanceOf(UnsupportedOperationException.class);
+    }
+
     @Test
     public void whenCollectingToMapwWithDuplicates_shouldCollectToMapMergingTheIdenticalItems() throws Exception {
         final Map<String, Integer> result = listWithDuplicates.stream().collect(

core-java-modules/core-java-11-2/src/test/java/com/baeldung/features/HttpClientIntegrationTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.features;
+
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.mockserver.integration.ClientAndServer;
+import org.mockserver.model.HttpStatusCode;
+import org.mockserver.socket.PortFactory;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockserver.integration.ClientAndServer.startClientAndServer;
+
+class HttpClientIntegrationTest {
+
+    private static ClientAndServer mockServer;
+    private static int port;
+
+    @BeforeAll
+    static void startServer() {
+        port = PortFactory.findFreePort();
+        mockServer = startClientAndServer(port);
+        mockServer.when(new org.mockserver.model.HttpRequest().withMethod("GET"))
+          .respond(new org.mockserver.model.HttpResponse()
+            .withStatusCode(HttpStatusCode.OK_200.code())
+            .withBody("Hello from the server!"));
+    }
+
+    @AfterAll
+    static void stopServer() {
+        mockServer.stop();
+    }
+
+    @Test
+    void givenSampleHttpRequest_whenRequestIsSent_thenServerResponseIsReceived() throws IOException, InterruptedException {
+        HttpClient httpClient = HttpClient.newBuilder()
+          .version(HttpClient.Version.HTTP_2)
+          .connectTimeout(Duration.ofSeconds(20))
+          .build();
+        HttpRequest httpRequest = HttpRequest.newBuilder()
+          .GET()
+          .uri(URI.create("http://localhost:" + port))
+          .build();
+        HttpResponse<String> httpResponse = httpClient.send(httpRequest, HttpResponse.BodyHandlers.ofString());
+        assertThat(httpResponse.body()).isEqualTo("Hello from the server!");
+    }
+
+}

core-java-modules/core-java-11-2/src/test/java/com/baeldung/features/JavaElevenFeaturesUnitTest.java

@@ -0,0 +1,61 @@
+package com.baeldung.features;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import javax.annotation.Nonnull;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class JavaElevenFeaturesUnitTest {
+
+    @Test
+    void givenMultilineString_whenExtractingNonBlankStrippedLines_thenLinesAreReturned() {
+        String multilineString = "Baeldung helps \n \n developers \n explore Java.";
+        List<String> lines = multilineString.lines()
+          .filter(line -> !line.isBlank())
+          .map(String::strip)
+          .collect(Collectors.toList());
+        assertThat(lines).containsExactly("Baeldung helps", "developers", "explore Java.");
+    }
+
+    @Test
+    void givenTemporaryFile_whenReadingStringContent_thenContentIsReturned(@TempDir Path tempDir) throws IOException {
+        Path filePath = Files.writeString(Files.createTempFile(tempDir, "demo", ".txt"), "Sample text");
+        String fileContent = Files.readString(filePath);
+        assertThat(fileContent).isEqualTo("Sample text");
+    }
+
+    @Test
+    void givenSampleList_whenConvertingToArray_thenItemsRemainUnchanged() {
+        List<String> sampleList = Arrays.asList("Java", "Kotlin");
+        String[] sampleArray = sampleList.toArray(String[]::new);
+        assertThat(sampleArray).containsExactly("Java", "Kotlin");
+    }
+
+    @Test
+    void givenSampleList_whenConvertingToUppercaseString_thenUppercaseIsReturned() {
+        List<String> sampleList = Arrays.asList("Java", "Kotlin");
+        String resultString = sampleList.stream()
+          .map((@Nonnull var x) -> x.toUpperCase())
+          .collect(Collectors.joining(", "));
+        assertThat(resultString).isEqualTo("JAVA, KOTLIN");
+    }
+
+    @Test
+    void givenSampleList_whenExtractingNonBlankValues_thenOnlyNonBlanksAreReturned() {
+        List<String> sampleList = Arrays.asList("Java", "\n \n", "Kotlin", " ");
+        List<String> withoutBlanks = sampleList.stream()
+          .filter(Predicate.not(String::isBlank))
+          .collect(Collectors.toList());
+        assertThat(withoutBlanks).containsExactly("Java", "Kotlin");
+    }
+
+}

core-java-modules/core-java-11-2/src/test/java/com/baeldung/features/NestedClassesUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.features;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class NestedClassesUnitTest {
+
+    @Test
+    public void giveNestedClass_whenCallingMainClassPrivateMethod_thenNoExceptionIsThrown() {
+        MainClass.NestedClass nestedInstance = new MainClass.NestedClass();
+        assertThat(nestedInstance.nestedPublicMethod()).isTrue();
+    }
+
+    @Test
+    public void giveNestedClass_whenCheckingNestmate_thenNestedClassIsReturned() {
+        assertThat(MainClass.class.isNestmateOf(MainClass.NestedClass.class)).isTrue();
+    }
+
+    @Test
+    public void giveNestedClass_whenCheckingNestHost_thenMainClassIsReturned() {
+        assertThat(MainClass.NestedClass.class.getNestHost()).isEqualTo(MainClass.class);
+    }
+
+    @Test
+    public void giveNestedClass_whenCheckingNestMembers_thenNestMembersAreReturned() {
+        Set<String> nestedMembers = Arrays.stream(MainClass.NestedClass.class.getNestMembers())
+          .map(Class::getName)
+          .collect(Collectors.toSet());
+        assertThat(nestedMembers).contains(MainClass.class.getName(), MainClass.NestedClass.class.getName());
+    }
+
+}

core-java-modules/core-java-11-2/src/test/java/com/baeldung/optional/OptionalChainingUnitTest.java

@@ -7,7 +7,9 @@ import java.util.Optional;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 public class OptionalChainingUnitTest {
 

core-java-modules/core-java-11-2/src/test/java/com/baeldung/optional/OptionalUnitTest.java

@@ -9,7 +9,9 @@ import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Optional;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 public class OptionalUnitTest {
 
@@ -262,6 +264,12 @@ public class OptionalUnitTest {
             .orElseThrow(IllegalArgumentException::new);
     }
 
+    @Test(expected = NoSuchElementException.class)
+    public void whenNoArgOrElseThrowWorks_thenCorrect() {
+        String nullName = null;
+        String name = Optional.ofNullable(nullName).orElseThrow();
+    }
+
     public String getMyDefault() {
         LOG.debug("Getting default value...");
         return "Default Value";

core-java-modules/core-java-11-2/src/test/java/com/baeldung/reflection/OperationsUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.junit.Assert.assertFalse;

core-java-modules/core-java-11-2/src/test/java/com/baeldung/reflection/ReflectionUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java.reflection;
+package com.baeldung.reflection;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -32,23 +32,23 @@ public class ReflectionUnitTest {
         final Class<?> clazz = goat.getClass();
 
         assertEquals("Goat", clazz.getSimpleName());
-        assertEquals("com.baeldung.java.reflection.Goat", clazz.getName());
-        assertEquals("com.baeldung.java.reflection.Goat", clazz.getCanonicalName());
+        assertEquals("com.baeldung.reflection.Goat", clazz.getName());
+        assertEquals("com.baeldung.reflection.Goat", clazz.getCanonicalName());
     }
 
     @Test
     public void givenClassName_whenCreatesObject_thenCorrect() throws ClassNotFoundException {
-        final Class<?> clazz = Class.forName("com.baeldung.java.reflection.Goat");
+        final Class<?> clazz = Class.forName("com.baeldung.reflection.Goat");
 
         assertEquals("Goat", clazz.getSimpleName());
-        assertEquals("com.baeldung.java.reflection.Goat", clazz.getName());
-        assertEquals("com.baeldung.java.reflection.Goat", clazz.getCanonicalName());
+        assertEquals("com.baeldung.reflection.Goat", clazz.getName());
+        assertEquals("com.baeldung.reflection.Goat", clazz.getCanonicalName());
     }
 
     @Test
     public void givenClass_whenRecognisesModifiers_thenCorrect() throws ClassNotFoundException {
-        final Class<?> goatClass = Class.forName("com.baeldung.java.reflection.Goat");
-        final Class<?> animalClass = Class.forName("com.baeldung.java.reflection.Animal");
+        final Class<?> goatClass = Class.forName("com.baeldung.reflection.Goat");
+        final Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
         final int goatMods = goatClass.getModifiers();
         final int animalMods = animalClass.getModifiers();
 
@@ -63,7 +63,7 @@ public class ReflectionUnitTest {
         final Class<?> goatClass = goat.getClass();
         final Package pkg = goatClass.getPackage();
 
-        assertEquals("com.baeldung.java.reflection", pkg.getName());
+        assertEquals("com.baeldung.reflection", pkg.getName());
     }
 
     @Test
@@ -81,8 +81,8 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsImplementedInterfaces_thenCorrect() throws ClassNotFoundException {
-        final Class<?> goatClass = Class.forName("com.baeldung.java.reflection.Goat");
-        final Class<?> animalClass = Class.forName("com.baeldung.java.reflection.Animal");
+        final Class<?> goatClass = Class.forName("com.baeldung.reflection.Goat");
+        final Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
         final Class<?>[] goatInterfaces = goatClass.getInterfaces();
         final Class<?>[] animalInterfaces = animalClass.getInterfaces();
 
@@ -94,16 +94,16 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsConstructor_thenCorrect() throws ClassNotFoundException {
-        final Class<?> goatClass = Class.forName("com.baeldung.java.reflection.Goat");
+        final Class<?> goatClass = Class.forName("com.baeldung.reflection.Goat");
         final Constructor<?>[] constructors = goatClass.getConstructors();
 
         assertEquals(1, constructors.length);
-        assertEquals("com.baeldung.java.reflection.Goat", constructors[0].getName());
+        assertEquals("com.baeldung.reflection.Goat", constructors[0].getName());
     }
 
     @Test
     public void givenClass_whenGetsFields_thenCorrect() throws ClassNotFoundException {
-        final Class<?> animalClass = Class.forName("com.baeldung.java.reflection.Animal");
+        final Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
         final Field[] fields = animalClass.getDeclaredFields();
 
         final List<String> actualFields = getFieldNames(fields);
@@ -114,7 +114,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsMethods_thenCorrect() throws ClassNotFoundException {
-        final Class<?> animalClass = Class.forName("com.baeldung.java.reflection.Animal");
+        final Class<?> animalClass = Class.forName("com.baeldung.reflection.Animal");
         final Method[] methods = animalClass.getDeclaredMethods();
         final List<String> actualMethods = getMethodNames(methods);
 
@@ -124,7 +124,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsAllConstructors_thenCorrect() throws ClassNotFoundException {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Constructor<?>[] constructors = birdClass.getConstructors();
 
         assertEquals(3, constructors.length);
@@ -132,7 +132,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsEachConstructorByParamTypes_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         birdClass.getConstructor();
         birdClass.getConstructor(String.class);
         birdClass.getConstructor(String.class, boolean.class);
@@ -140,7 +140,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenInstantiatesObjectsAtRuntime_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
 
         final Constructor<?> cons1 = birdClass.getConstructor();
         final Constructor<?> cons2 = birdClass.getConstructor(String.class);
@@ -159,7 +159,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsPublicFields_thenCorrect() throws ClassNotFoundException {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Field[] fields = birdClass.getFields();
         assertEquals(1, fields.length);
         assertEquals("CATEGORY", fields[0].getName());
@@ -168,7 +168,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsPublicFieldByName_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Field field = birdClass.getField("CATEGORY");
         assertEquals("CATEGORY", field.getName());
 
@@ -176,7 +176,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsDeclaredFields_thenCorrect() throws ClassNotFoundException {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Field[] fields = birdClass.getDeclaredFields();
         assertEquals(1, fields.length);
         assertEquals("walks", fields[0].getName());
@@ -184,7 +184,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsFieldsByName_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Field field = birdClass.getDeclaredField("walks");
         assertEquals("walks", field.getName());
 
@@ -192,14 +192,14 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClassField_whenGetsType_thenCorrect() throws Exception {
-        final Field field = Class.forName("com.baeldung.java.reflection.Bird").getDeclaredField("walks");
+        final Field field = Class.forName("com.baeldung.reflection.Bird").getDeclaredField("walks");
         final Class<?> fieldClass = field.getType();
         assertEquals("boolean", fieldClass.getSimpleName());
     }
 
     @Test
     public void givenClassField_whenSetsAndGetsValue_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Bird bird = (Bird) birdClass.getConstructor().newInstance();
         final Field field = birdClass.getDeclaredField("walks");
         field.setAccessible(true);
@@ -216,7 +216,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClassField_whenGetsAndSetsWithNull_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Field field = birdClass.getField("CATEGORY");
         field.setAccessible(true);
 
@@ -225,7 +225,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsAllPublicMethods_thenCorrect() throws ClassNotFoundException {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Method[] methods = birdClass.getMethods();
         final List<String> methodNames = getMethodNames(methods);
 
@@ -235,7 +235,7 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenClass_whenGetsOnlyDeclaredMethods_thenCorrect() throws ClassNotFoundException {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final List<String> actualMethodNames = getMethodNames(birdClass.getDeclaredMethods());
 
         final List<String> expectedMethodNames = Arrays.asList("setWalks", "walks", "getSound", "eats");
@@ -248,24 +248,17 @@ public class ReflectionUnitTest {
 
     @Test
     public void givenMethodName_whenGetsMethod_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
-        final Method walksMethod = birdClass.getDeclaredMethod("walks");
-        final Method setWalksMethod = birdClass.getDeclaredMethod("setWalks", boolean.class);
-
-        assertFalse(walksMethod.isAccessible());
-        assertFalse(setWalksMethod.isAccessible());
-
-        walksMethod.setAccessible(true);
-        setWalksMethod.setAccessible(true);
-
-        assertTrue(walksMethod.isAccessible());
-        assertTrue(setWalksMethod.isAccessible());
+        final Bird bird = new Bird();
+        final Method walksMethod = bird.getClass().getDeclaredMethod("walks");
+        final Method setWalksMethod = bird.getClass().getDeclaredMethod("setWalks", boolean.class);
 
+        assertTrue(walksMethod.canAccess(bird));
+        assertTrue(setWalksMethod.canAccess(bird));
     }
 
     @Test
     public void givenMethod_whenInvokes_thenCorrect() throws Exception {
-        final Class<?> birdClass = Class.forName("com.baeldung.java.reflection.Bird");
+        final Class<?> birdClass = Class.forName("com.baeldung.reflection.Bird");
         final Bird bird = (Bird) birdClass.getConstructor().newInstance();
         final Method setWalksMethod = birdClass.getDeclaredMethod("setWalks", boolean.class);
         final Method walksMethod = birdClass.getDeclaredMethod("walks");