BAEL-2492 Rename WireMockScenario test class

core-groovy/src/main/groovy/com/baeldung/traits/AnimalTrait.groovy

@@ -0,0 +1,8 @@
+package com.baeldung.traits
+
+trait AnimalTrait {
+    
+    String basicBehavior() {
+        return "Animalistic!!"
+    }
+}

core-groovy/src/main/groovy/com/baeldung/traits/Dog.groovy

@@ -0,0 +1,9 @@
+package com.baeldung.traits
+
+class Dog implements WalkingTrait, SpeakingTrait {
+     
+    String speakAndWalk() {
+        WalkingTrait.super.speakAndWalk()
+    }
+    
+}

core-groovy/src/main/groovy/com/baeldung/traits/Employee.groovy

@@ -0,0 +1,12 @@
+package com.baeldung.traits
+
+class Employee implements UserTrait {
+    
+    String name() {
+        return 'Bob'
+    }
+    
+    String lastName() {
+        return "Marley"
+    }
+}

core-groovy/src/main/groovy/com/baeldung/traits/Human.groovy

@@ -0,0 +1,6 @@
+package com.baeldung.traits
+
+interface Human {
+    
+    String lastName()
+}

core-groovy/src/main/groovy/com/baeldung/traits/SpeakingTrait.groovy

@@ -0,0 +1,13 @@
+package com.baeldung.traits
+
+trait SpeakingTrait {
+    
+    String basicAbility() {
+        return "Speaking!!"
+    }
+    
+    String speakAndWalk() {
+        return "Speak and walk!!"
+    }
+    
+}

core-groovy/src/main/groovy/com/baeldung/traits/UserTrait.groovy

@@ -0,0 +1,36 @@
+package com.baeldung.traits
+
+trait UserTrait implements Human {
+    
+    String sayHello() {
+        return "Hello!"
+    }
+    
+    abstract String name()
+    
+    String showName() {
+       return "Hello, ${name()}!"
+    }
+
+    private String greetingMessage() {
+        return 'Hello, from a private method!'
+    }
+    
+    String greet() {
+        def msg = greetingMessage()
+        println msg
+        msg
+    }
+    
+    def whoAmI() {
+        return this 
+    }
+    
+    String showLastName() {
+        return "Hello, ${lastName()}!"
+    }
+    
+    String email
+    String address
+}
+    

core-groovy/src/main/groovy/com/baeldung/traits/WalkingTrait.groovy

@@ -0,0 +1,13 @@
+package com.baeldung.traits
+
+trait WalkingTrait {
+    
+    String basicAbility() {
+        return "Walking!!"
+    }
+    
+    String speakAndWalk() {
+        return "Walk and speak!!"
+    }
+    
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/CharacterInGroovy.groovy

@@ -0,0 +1,19 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Assert
+import org.junit.Test
+
+class CharacterInGroovy {
+
+    @Test
+    void 'character'() {
+        char a = 'A' as char
+        char b = 'B' as char
+        char c = (char) 'C'
+
+        Assert.assertTrue(a instanceof Character)
+        Assert.assertTrue(b instanceof Character)
+        Assert.assertTrue(c instanceof Character)
+    }
+
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/DollarSlashyString.groovy

@@ -0,0 +1,24 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Test
+
+class DollarSlashyString {
+
+    @Test
+    void 'dollar slashy string'() {
+        def name = "John"
+
+        def dollarSlashy = $/
+            Hello $name!,
+
+            I can show you $ sign or escaped dollar sign: $$ 
+            Both slashes works: \ or /, but we can still escape it: $/
+            
+            We have to escape opening and closing delimiter:
+            - $$$/  
+            - $/$$
+        /$
+
+        print(dollarSlashy)
+    }
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/DoubleQuotedString.groovy

@@ -0,0 +1,67 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Assert
+import org.junit.Test
+
+class DoubleQuotedString {
+
+    @Test
+    void 'escape double quoted string'() {
+        def example = "Hello \"world\"!"
+
+        println(example)
+    }
+
+    @Test
+    void 'String ang GString'() {
+        def string = "example"
+        def stringWithExpression = "example${2}"
+
+        Assert.assertTrue(string instanceof String)
+        Assert.assertTrue(stringWithExpression instanceof GString)
+        Assert.assertTrue(stringWithExpression.toString() instanceof String)
+    }
+
+    @Test
+    void 'placeholder with variable'() {
+        def name = "John"
+        def helloName = "Hello $name!".toString()
+
+        Assert.assertEquals("Hello John!", helloName)
+    }
+
+    @Test
+    void 'placeholder with expression'() {
+        def result = "result is ${2 * 2}".toString()
+
+        Assert.assertEquals("result is 4", result)
+    }
+
+    @Test
+    void 'placeholder with dotted access'() {
+        def person = [name: 'John']
+
+        def myNameIs = "I'm $person.name, and you?".toString()
+
+        Assert.assertEquals("I'm John, and you?", myNameIs)
+    }
+
+    @Test
+    void 'placeholder with method call'() {
+        def name = 'John'
+
+        def result = "Uppercase name: ${name.toUpperCase()}".toString()
+
+        Assert.assertEquals("Uppercase name: JOHN", result)
+    }
+
+
+    @Test
+    void 'GString and String hashcode'() {
+        def string = "2+2 is 4"
+        def gstring = "2+2 is ${4}"
+
+        Assert.assertTrue(string.hashCode() != gstring.hashCode())
+    }
+
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/SingleQuotedString.groovy

@@ -0,0 +1,15 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Assert
+import org.junit.Test
+
+class SingleQuotedString {
+
+    @Test
+    void 'single quoted string'() {
+        def example = 'Hello world'
+
+        Assert.assertEquals('Hello world!', 'Hello' + ' world!')
+    }
+
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/SlashyString.groovy

@@ -0,0 +1,31 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Assert
+import org.junit.Test
+
+class SlashyString {
+
+    @Test
+    void 'slashy string'() {
+        def pattern = /.*foobar.*\/hello.*/
+
+        Assert.assertTrue("I'm matching foobar /hello regexp pattern".matches(pattern))
+    }
+
+    void 'wont compile'() {
+//        if ('' == //) {
+//            println("I can't compile")
+//        }
+    }
+
+    @Test
+    void 'interpolate and multiline'() {
+        def name = 'John'
+
+        def example = /
+            Hello $name
+            second line        
+        /
+    }
+
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/Strings.groovy

@@ -0,0 +1,26 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Assert
+import org.junit.Test
+
+class Strings {
+
+    @Test
+    void 'string interpolation '() {
+        def name = "Kacper"
+
+        def result = "Hello ${name}!"
+
+        Assert.assertEquals("Hello Kacper!", result.toString())
+    }
+
+    @Test
+    void 'string concatenation'() {
+        def first = "first"
+        def second = "second"
+
+        def concatenation = first + second
+
+        Assert.assertEquals("firstsecond", concatenation)
+    }
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/TripleDoubleQuotedString.groovy

@@ -0,0 +1,19 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Test
+
+class TripleDoubleQuotedString {
+
+    @Test
+    void 'triple-quoted strings with interpolation'() {
+        def name = "John"
+
+        def multiLine = """
+            I'm $name.
+            "This is quotation"
+        """
+
+        println(multiLine)
+    }
+
+}

core-groovy/src/test/groovy/com/baeldung/stringtypes/TripleSingleQuotedString.groovy

@@ -0,0 +1,67 @@
+package groovy.com.baeldung.stringtypes
+
+import org.junit.Assert
+import org.junit.Test
+
+class TripleSingleQuotedString {
+
+    def 'formatted json'() {
+        def jsonContent = '''
+        {
+            "name": "John",
+            "age": 20,
+            "birthDate": null
+        }
+        '''
+    }
+
+    def 'triple single quoted'() {
+        def triple = '''im triple single quoted string'''
+    }
+
+    @Test
+    void 'triple single quoted with multiline string'() {
+        def triple = '''
+            firstline
+            secondline
+        '''
+
+        Assert.assertTrue(triple.startsWith("\n"))
+    }
+
+    @Test
+    void 'triple single quoted with multiline string with stripIndent() and removing newline characters'() {
+        def triple = '''\
+            firstline
+            secondline'''.stripIndent()
+
+        Assert.assertEquals("firstline\nsecondline", triple)
+    }
+
+    @Test
+    void 'triple single quoted with multiline string with last line with only whitespaces'() {
+        def triple = '''\
+            firstline
+                secondline\
+        '''.stripIndent()
+
+        println(triple)
+    }
+
+    @Test
+    void 'triple single quoted with multiline string with stripMargin(Character) and removing newline characters'() {
+        def triple = '''\
+            |firstline
+            |secondline'''.stripMargin()
+
+        println(triple)
+    }
+
+    @Test
+    void 'striple single quoted with special characters'() {
+        def specialCharacters = '''hello \'John\'. This is backslash - \\. \nSecond line starts here'''
+
+        println(specialCharacters)
+    }
+
+}

core-groovy/src/test/groovy/com/baeldung/traits/TraitsUnitTest.groovy

@@ -0,0 +1,114 @@
+package com.baeldung.traits
+
+import spock.lang.Specification
+
+class TraitsUnitTest extends Specification {
+
+    Employee employee
+    Dog dog
+
+    void setup () {
+        employee = new Employee()
+        dog = new Dog()
+    }
+
+    def 'Should return msg string when using Employee.sayHello method provided by UserTrait' () {
+        when:
+            def msg = employee.sayHello()
+        then:
+            msg
+            msg instanceof String
+            assert msg == "Hello!"
+    }
+    
+    def 'Should return displayMsg string when using Employee.showName method' () {
+        when:
+            def displayMsg = employee.showName()
+        then:
+            displayMsg
+            displayMsg instanceof String
+            assert displayMsg == "Hello, Bob!"
+    }
+    
+    def 'Should return greetMsg string when using Employee.greet method' () {
+        when:
+            def greetMsg = employee.greet()
+        then:
+            greetMsg
+            greetMsg instanceof String
+            assert greetMsg == "Hello, from a private method!"
+    }
+    
+    def 'Should return MissingMethodException when using Employee.greetingMessage method' () {
+        when:
+            def exception
+            try {
+                employee.greetingMessage()
+            }catch(Exception e) {
+                exception = e
+            }
+            
+        then:
+            exception
+            exception instanceof groovy.lang.MissingMethodException
+            assert exception.message == "No signature of method: com.baeldung.traits.Employee.greetingMessage()"+
+            " is applicable for argument types: () values: []"
+    }
+    
+    def 'Should return employee instance when using Employee.whoAmI method' () {
+        when:
+            def emp = employee.whoAmI()
+        then:
+            emp
+            emp instanceof Employee
+            assert emp.is(employee)
+    }
+    
+    def 'Should display lastName when using Employee.showLastName method' () {
+        when:
+            def lastNameMsg = employee.showLastName()
+        then:
+            lastNameMsg
+            lastNameMsg instanceof String
+            assert lastNameMsg == "Hello, Marley!"
+    }
+    
+    def 'Should be able to define properties of UserTrait in Employee instance' () {
+        when:
+            employee = new Employee(email: "[email protected]", address: "baeldung.com")
+        then:
+            employee
+            employee instanceof Employee
+            assert employee.email == "[email protected]"
+            assert employee.address == "baeldung.com"
+    }
+    
+    def 'Should execute basicAbility method from SpeakingTrait and return msg string' () {
+        when:
+            def speakMsg = dog.basicAbility()
+        then:
+            speakMsg
+            speakMsg instanceof String
+            assert speakMsg == "Speaking!!"
+    }
+    
+    def 'Should verify multiple inheritance with traits and execute overridden traits method' () {
+        when:
+            def walkSpeakMsg = dog.speakAndWalk()
+            println walkSpeakMsg
+        then:
+            walkSpeakMsg
+            walkSpeakMsg instanceof String
+            assert walkSpeakMsg == "Walk and speak!!"
+    }
+    
+    def 'Should implement AnimalTrait at runtime and access basicBehavior method' () {
+        when:
+            def dogInstance = new Dog() as AnimalTrait
+            def basicBehaviorMsg = dogInstance.basicBehavior()
+        then:
+            basicBehaviorMsg
+            basicBehaviorMsg instanceof String
+            assert basicBehaviorMsg == "Animalistic!!"
+    }
+}

core-java-11/src/main/java/com/baeldung/java11/httpclient/HttpClientExample.java

@@ -0,0 +1,132 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package com.baeldung.java11.httpclient;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpClient.Version;
+import java.net.http.HttpRequest;
+import java.net.http.HttpRequest.BodyPublishers;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.net.http.HttpResponse.PushPromiseHandler;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class HttpClientExample {
+
+    public static void main(String[] args) throws Exception {
+        httpGetRequest();
+        httpPostRequest();
+        asynchronousGetRequest();
+        asynchronousMultipleRequests();
+        pushRequest();
+    }
+
+    public static void httpGetRequest() throws URISyntaxException, IOException, InterruptedException {
+        HttpClient client = HttpClient.newHttpClient();
+        HttpRequest request = HttpRequest.newBuilder()
+            .version(HttpClient.Version.HTTP_2)
+            .uri(URI.create("http://jsonplaceholder.typicode.com/posts/1"))
+            .headers("Accept-Enconding", "gzip, deflate")
+            .build();
+        HttpResponse<String> response = client.send(request, BodyHandlers.ofString());
+
+        String responseBody = response.body();
+        int responseStatusCode = response.statusCode();
+
+        System.out.println("httpGetRequest: " + responseBody);
+        System.out.println("httpGetRequest status code: " + responseStatusCode);
+    }
+
+    public static void httpPostRequest() throws URISyntaxException, IOException, InterruptedException {
+        HttpClient client = HttpClient.newBuilder()
+            .version(HttpClient.Version.HTTP_2)
+            .build();
+        HttpRequest request = HttpRequest.newBuilder(new URI("http://jsonplaceholder.typicode.com/posts"))
+            .version(HttpClient.Version.HTTP_2)
+            .POST(BodyPublishers.ofString("Sample Post Request"))
+            .build();
+        HttpResponse<String> response = client.send(request, BodyHandlers.ofString());
+        String responseBody = response.body();
+        System.out.println("httpPostRequest : " + responseBody);
+    }
+
+    public static void asynchronousGetRequest() throws URISyntaxException {
+        HttpClient client = HttpClient.newHttpClient();
+        URI httpURI = new URI("http://jsonplaceholder.typicode.com/posts/1");
+        HttpRequest request = HttpRequest.newBuilder(httpURI)
+            .version(HttpClient.Version.HTTP_2)
+            .build();
+        CompletableFuture<Void> futureResponse = client.sendAsync(request, HttpResponse.BodyHandlers.ofString())
+            .thenAccept(resp -> {
+                System.out.println("Got pushed response " + resp.uri());
+                System.out.println("Response statuscode: " + resp.statusCode());
+                System.out.println("Response body: " + resp.body());
+            });
+        System.out.println("futureResponse" + futureResponse);
+
+    }
+
+    public static void asynchronousMultipleRequests() throws URISyntaxException {
+        HttpClient client = HttpClient.newHttpClient();
+        List<URI> uris = Arrays.asList(new URI("http://jsonplaceholder.typicode.com/posts/1"), new URI("http://jsonplaceholder.typicode.com/posts/2"));
+        List<HttpRequest> requests = uris.stream()
+            .map(HttpRequest::newBuilder)
+            .map(reqBuilder -> reqBuilder.build())
+            .collect(Collectors.toList());
+        System.out.println("Got pushed response1 " + requests);
+        CompletableFuture.allOf(requests.stream()
+            .map(request -> client.sendAsync(request, BodyHandlers.ofString()))
+            .toArray(CompletableFuture<?>[]::new))
+            .thenAccept(System.out::println)
+            .join();
+    }
+
+    public static void pushRequest() throws URISyntaxException, InterruptedException {
+        System.out.println("Running HTTP/2 Server Push example...");
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .version(Version.HTTP_2)
+            .build();
+
+        HttpRequest pageRequest = HttpRequest.newBuilder()
+            .uri(URI.create("https://http2.golang.org/serverpush"))
+            .build();
+
+        // Interface HttpResponse.PushPromiseHandler<T>
+        // void applyPushPromise​(HttpRequest initiatingRequest, HttpRequest pushPromiseRequest, Function<HttpResponse.BodyHandler<T>,​CompletableFuture<HttpResponse<T>>> acceptor)
+        httpClient.sendAsync(pageRequest, BodyHandlers.ofString(), pushPromiseHandler())
+            .thenAccept(pageResponse -> {
+                System.out.println("Page response status code: " + pageResponse.statusCode());
+                System.out.println("Page response headers: " + pageResponse.headers());
+                String responseBody = pageResponse.body();
+                System.out.println(responseBody);
+            }).join();
+
+        Thread.sleep(1000); // waiting for full response
+    }
+
+    private static PushPromiseHandler<String> pushPromiseHandler() {
+        return (HttpRequest initiatingRequest, 
+            HttpRequest pushPromiseRequest, 
+            Function<HttpResponse.BodyHandler<String>, 
+            CompletableFuture<HttpResponse<String>>> acceptor) -> {
+            acceptor.apply(BodyHandlers.ofString())
+                .thenAccept(resp -> {
+                    System.out.println(" Pushed response: " + resp.uri() + ", headers: " + resp.headers());
+                });
+            System.out.println("Promise request: " + pushPromiseRequest.uri());
+            System.out.println("Promise request: " + pushPromiseRequest.headers());
+        };
+    }
+
+}

core-java-11/src/test/java/com/baeldung/java11/httpclient/test/HttpClientTest.java

@@ -0,0 +1,240 @@
+package com.baeldung.java11.httpclient.test;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.IOException;
+import java.net.Authenticator;
+import java.net.CookieManager;
+import java.net.CookiePolicy;
+import java.net.HttpURLConnection;
+import java.net.PasswordAuthentication;
+import java.net.ProxySelector;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.Test;
+
+public class HttpClientTest {
+
+    @Test
+    public void shouldReturnSampleDataContentWhenConnectViaSystemProxy() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofString("Sample body"))
+            .build();
+      
+        
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .proxy(ProxySelector.getDefault())
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+        
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample body"));
+    }
+
+    @Test
+    public void shouldNotFollowRedirectWhenSetToDefaultNever() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_1_1)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_MOVED_PERM));
+        assertThat(response.body(), containsString("https://stackoverflow.com/"));
+    }
+
+    @Test
+    public void shouldFollowRedirectWhenSetToAlways() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_1_1)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .followRedirects(HttpClient.Redirect.ALWAYS)
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.request()
+            .uri()
+            .toString(), equalTo("https://stackoverflow.com/"));
+    }
+
+    @Test
+    public void shouldReturnOKStatusForAuthenticatedAccess() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/basic-auth"))
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .authenticator(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication("postman", "password".toCharArray());
+                }
+            })
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldSendRequestAsync() throws URISyntaxException, InterruptedException, ExecutionException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofString("Sample body"))
+            .build();
+        CompletableFuture<HttpResponse<String>> response = HttpClient.newBuilder()
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldUseJustTwoThreadWhenProcessingSendAsyncRequest() throws URISyntaxException, InterruptedException, ExecutionException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        ExecutorService executorService = Executors.newFixedThreadPool(2);
+
+        CompletableFuture<HttpResponse<String>> response1 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        CompletableFuture<HttpResponse<String>> response2 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        CompletableFuture<HttpResponse<String>> response3 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        CompletableFuture.allOf(response1, response2, response3)
+            .join();
+
+        assertThat(response1.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response2.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response3.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldNotStoreCookieWhenPolicyAcceptNone() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .cookieHandler(new CookieManager(null, CookiePolicy.ACCEPT_NONE))
+            .build();
+
+        httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertTrue(httpClient.cookieHandler()
+            .isPresent());
+    }
+
+    @Test
+    public void shouldStoreCookieWhenPolicyAcceptAll() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .cookieHandler(new CookieManager(null, CookiePolicy.ACCEPT_ALL))
+            .build();
+
+        httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertTrue(httpClient.cookieHandler()
+            .isPresent());
+    }
+
+    @Test
+    public void shouldProcessMultipleRequestViaStream() throws URISyntaxException, ExecutionException, InterruptedException {
+        List<URI> targets = Arrays.asList(new URI("https://postman-echo.com/get?foo1=bar1"), new URI("https://postman-echo.com/get?foo2=bar2"));
+
+        HttpClient client = HttpClient.newHttpClient();
+
+        List<CompletableFuture<String>> futures = targets.stream()
+            .map(target -> client.sendAsync(HttpRequest.newBuilder(target)
+                .GET()
+                .build(), HttpResponse.BodyHandlers.ofString())
+                .thenApply(response -> response.body()))
+            .collect(Collectors.toList());
+
+        CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
+            .join();
+
+        if (futures.get(0)
+            .get()
+            .contains("foo1")) {
+            assertThat(futures.get(0)
+                .get(), containsString("bar1"));
+            assertThat(futures.get(1)
+                .get(), containsString("bar2"));
+        } else {
+            assertThat(futures.get(1)
+                .get(), containsString("bar2"));
+            assertThat(futures.get(1)
+                .get(), containsString("bar1"));
+        }
+
+    }
+    
+    @Test
+    public void completeExceptionallyExample() {
+        CompletableFuture<String> cf = CompletableFuture.completedFuture("message").thenApplyAsync(String::toUpperCase,
+                CompletableFuture.delayedExecutor(1, TimeUnit.SECONDS));
+        CompletableFuture<String> exceptionHandler = cf.handle((s, th) -> { return (th != null) ? "message upon cancel" : ""; });
+        cf.completeExceptionally(new RuntimeException("completed exceptionally"));
+        assertTrue("Was not completed exceptionally", cf.isCompletedExceptionally());
+        try {
+            cf.join();
+            fail("Should have thrown an exception");
+        } catch (CompletionException ex) { // just for testing
+            assertEquals("completed exceptionally", ex.getCause().getMessage());
+        }
+
+        assertEquals("message upon cancel", exceptionHandler.join());
+    }
+
+}

core-java-11/src/test/java/com/baeldung/java11/httpclient/test/HttpRequestTest.java

@@ -0,0 +1,168 @@
+package com.baeldung.java11.httpclient.test;
+
+import static java.time.temporal.ChronoUnit.SECONDS;
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.nio.file.Paths;
+import java.security.NoSuchAlgorithmException;
+import java.time.Duration;
+
+import org.junit.Test;
+
+public class HttpRequestTest {
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequest() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldUseHttp2WhenWebsiteUsesHttp2() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_2)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.version(), equalTo(HttpClient.Version.HTTP_2));
+    }
+
+    @Test
+    public void shouldFallbackToHttp1_1WhenWebsiteDoesNotUseHttp2() throws IOException, InterruptedException, URISyntaxException, NoSuchAlgorithmException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .version(HttpClient.Version.HTTP_2)
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.version(), equalTo(HttpClient.Version.HTTP_1_1));
+    }
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequestWithDummyHeaders() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .headers("key1", "value1", "key2", "value2")
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequestTimeoutSet() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .timeout(Duration.of(10, SECONDS))
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldReturnNoContentWhenPostWithNoBody() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .POST(HttpRequest.BodyPublishers.noBody())
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithBodyText() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofString("Sample request body"))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample request body"));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithInputStream() throws IOException, InterruptedException, URISyntaxException {
+        byte[] sampleData = "Sample request body".getBytes();
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofInputStream(() -> new ByteArrayInputStream(sampleData)))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample request body"));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithByteArrayProcessorStream() throws IOException, InterruptedException, URISyntaxException {
+        byte[] sampleData = "Sample request body".getBytes();
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofByteArray(sampleData))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample request body"));
+    }
+
+    @Test
+    public void shouldReturnSampleDataContentWhenPostWithFileProcessorStream() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofFile(Paths.get("src/test/resources/sample.txt")))
+            .build();
+
+        HttpResponse<String> response = HttpClient.newHttpClient()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample file content"));
+    }
+
+}

core-java-11/src/test/java/com/baeldung/java11/httpclient/test/HttpResponseTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.java11.httpclient.test;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThat;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+
+import org.junit.Test;
+
+public class HttpResponseTest {
+
+    @Test
+    public void shouldReturnStatusOKWhenSendGetRequest() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .version(HttpClient.Version.HTTP_2)
+            .GET()
+            .build();
+
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .followRedirects(HttpClient.Redirect.NORMAL)
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertNotNull(response.body());
+    }
+
+    @Test
+    public void shouldResponseURIDifferentThanRequestUIRWhenRedirect() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_2)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .followRedirects(HttpClient.Redirect.NORMAL)
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(request.uri()
+            .toString(), equalTo("http://stackoverflow.com"));
+        assertThat(response.uri()
+            .toString(), equalTo("https://stackoverflow.com/"));
+    }
+
+}

core-java-8/src/main/java/com/baeldung/customannotations/Init.java

@@ -0,0 +1,13 @@
+package com.baeldung.customannotations;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+@Retention(RUNTIME)
+@Target(METHOD)
+public @interface Init {
+
+}

core-java-8/src/main/java/com/baeldung/customannotations/JsonElement.java

@@ -0,0 +1,13 @@
+package com.baeldung.customannotations;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+@Retention(RUNTIME)
+@Target({ FIELD })
+public @interface JsonElement {
+    public String key() default "";
+}

core-java-8/src/main/java/com/baeldung/customannotations/JsonSerializable.java

@@ -0,0 +1,13 @@
+package com.baeldung.customannotations;
+
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+@Retention(RUNTIME)
+@Target(TYPE)
+public @interface JsonSerializable {
+
+}

core-java-8/src/main/java/com/baeldung/customannotations/JsonSerializationException.java

@@ -0,0 +1,10 @@
+package com.baeldung.customannotations;
+
+public class JsonSerializationException extends RuntimeException {
+
+    private static final long serialVersionUID = 1L;
+
+    public JsonSerializationException(String message) {
+        super(message);
+    }
+}

core-java-8/src/main/java/com/baeldung/customannotations/ObjectToJsonConverter.java

@@ -0,0 +1,67 @@
+package com.baeldung.customannotations;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+public class ObjectToJsonConverter {
+    public String convertToJson(Object object) throws JsonSerializationException {
+        try {
+
+            checkIfSerializable(object);
+            initializeObject(object);
+            return getJsonString(object);
+
+        } catch (Exception e) {
+            throw new JsonSerializationException(e.getMessage());
+        }
+    }
+
+    private void checkIfSerializable(Object object) {
+        if (Objects.isNull(object)) {
+            throw new JsonSerializationException("Can't serialize a null object");
+        }
+
+        Class<?> clazz = object.getClass();
+        if (!clazz.isAnnotationPresent(JsonSerializable.class)) {
+            throw new JsonSerializationException("The class " + clazz.getSimpleName() + " is not annotated with JsonSerializable");
+        }
+    }
+
+    private void initializeObject(Object object) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
+        Class<?> clazz = object.getClass();
+        for (Method method : clazz.getDeclaredMethods()) {
+            if (method.isAnnotationPresent(Init.class)) {
+                method.setAccessible(true);
+                method.invoke(object);
+            }
+        }
+    }
+
+    private String getJsonString(Object object) throws IllegalArgumentException, IllegalAccessException {
+        Class<?> clazz = object.getClass();
+        Map<String, String> jsonElementsMap = new HashMap<>();
+        for (Field field : clazz.getDeclaredFields()) {
+            field.setAccessible(true);
+            if (field.isAnnotationPresent(JsonElement.class)) {
+                jsonElementsMap.put(getKey(field), (String) field.get(object));
+            }
+        }
+
+        String jsonString = jsonElementsMap.entrySet()
+            .stream()
+            .map(entry -> "\"" + entry.getKey() + "\":\"" + entry.getValue() + "\"")
+            .collect(Collectors.joining(","));
+        return "{" + jsonString + "}";
+    }
+
+    private String getKey(Field field) {
+        String value = field.getAnnotation(JsonElement.class)
+            .key();
+        return value.isEmpty() ? field.getName() : value;
+    }
+}

core-java-8/src/main/java/com/baeldung/customannotations/Person.java

@@ -0,0 +1,66 @@
+package com.baeldung.customannotations;
+
+@JsonSerializable
+public class Person {
+    @JsonElement
+    private String firstName;
+    @JsonElement
+    private String lastName;
+    @JsonElement(key = "personAge")
+    private String age;
+
+    private String address;
+
+    public Person(String firstName, String lastName) {
+        super();
+        this.firstName = firstName;
+        this.lastName = lastName;
+    }
+
+    public Person(String firstName, String lastName, String age) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.age = age;
+    }
+
+    @Init
+    private void initNames() {
+        this.firstName = this.firstName.substring(0, 1)
+            .toUpperCase() + this.firstName.substring(1);
+        this.lastName = this.lastName.substring(0, 1)
+            .toUpperCase() + this.lastName.substring(1);
+    }
+
+    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;
+    }
+
+    public String getAge() {
+        return age;
+    }
+
+    public void setAge(String age) {
+        this.age = age;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+
+}

core-java-8/src/test/java/com/baeldung/collectors/Java8CollectorsUnitTest.java

@@ -85,10 +85,16 @@ public class Java8CollectorsUnitTest {
     }
 
     @Test
-    public void whenCollectingToMap_shouldCollectToMapMerging() throws Exception {
-        final Map<String, Integer> result = givenList.stream().collect(toMap(Function.identity(), String::length, (i1, i2) -> i1));
+    public void whenCollectingToMapwWithDuplicates_shouldCollectToMapMergingTheIdenticalItems() throws Exception {
+        final Map<String, Integer> result = listWithDuplicates.stream().collect(
+          toMap(
+            Function.identity(),
+            String::length,
+            (item, identicalItem) -> item
+          )
+        );
 
-        assertThat(result).containsEntry("a", 1).containsEntry("bb", 2).containsEntry("ccc", 3).containsEntry("dd", 2);
+        assertThat(result).containsEntry("a", 1).containsEntry("bb", 2).containsEntry("c", 1).containsEntry("d", 1);
     }
 
     @Test

core-java-8/src/test/java/com/baeldung/customannotations/JsonSerializerUnitTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.customannotations;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class JsonSerializerUnitTest {
+
+    @Test
+    public void givenObjectNotSerializedThenExceptionThrown() throws JsonSerializationException {
+        Object object = new Object();
+        ObjectToJsonConverter serializer = new ObjectToJsonConverter();
+        assertThrows(JsonSerializationException.class, () -> {
+            serializer.convertToJson(object);
+        });
+    }
+
+    @Test
+    public void givenObjectSerializedThenTrueReturned() throws JsonSerializationException {
+        Person person = new Person("soufiane", "cheouati", "34");
+        ObjectToJsonConverter serializer = new ObjectToJsonConverter();
+        String jsonString = serializer.convertToJson(person);
+        assertEquals("{\"personAge\":\"34\",\"firstName\":\"Soufiane\",\"lastName\":\"Cheouati\"}", jsonString);
+    }
+}

core-java-collections-list/src/main/java/com/baeldung/allequalelements/VerifyAllEqualListElements.java

@@ -0,0 +1,55 @@
+package com.baeldung.allequalelements;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import org.apache.commons.collections4.IterableUtils;
+import com.google.common.base.Predicate;
+import com.google.common.collect.Iterables;
+
+public class VerifyAllEqualListElements {
+
+    public boolean verifyAllEqualUsingALoop(List<String> list) {
+        for (String s : list) {
+            if (!s.equals(list.get(0)))
+                return false;
+        }
+        return true;
+    }
+
+    public boolean verifyAllEqualUsingHashSet(List<String> list) {
+        return new HashSet<String>(list).size() <= 1;
+    }
+
+    public boolean verifyAllEqualUsingFrequency(List<String> list) {
+        return list.isEmpty() || Collections.frequency(list, list.get(0)) == list.size();
+    }
+
+    public boolean verifyAllEqualUsingStream(List<String> list) {
+        return list.stream()
+            .distinct()
+            .count() <= 1;
+    }
+
+    public boolean verifyAllEqualAnotherUsingStream(List<String> list) {
+        return list.isEmpty() || list.stream()
+            .allMatch(list.get(0)::equals);
+    }
+
+    public boolean verifyAllEqualUsingGuava(List<String> list) {
+        return Iterables.all(list, new Predicate<String>() {
+            public boolean apply(String s) {
+                return s.equals(list.get(0));
+            }
+        });
+    }
+
+    public boolean verifyAllEqualUsingApacheCommon(List<String> list) {
+        return IterableUtils.matchesAll(list, new org.apache.commons.collections4.Predicate<String>() {
+            public boolean evaluate(String s) {
+                return s.equals(list.get(0));
+            }
+        });
+    }
+
+}

core-java-collections-list/src/test/java/com/baeldung/allequalelements/VerifyAllEqualListElementsUnitTest.java

@@ -0,0 +1,172 @@
+package com.baeldung.allequalelements;
+
+import org.junit.Test;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import static org.junit.Assert.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class VerifyAllEqualListElementsUnitTest {
+
+    private static List<String> notAllEqualList = new ArrayList<>();
+
+    private static List<String> emptyList = new ArrayList<>();
+
+    private static List<String> allEqualList = new ArrayList<>();
+
+    static {
+        notAllEqualList = Arrays.asList("Jack", "James", "Sam", "James");
+        emptyList = Arrays.asList();
+        allEqualList = Arrays.asList("Jack", "Jack", "Jack", "Jack");
+    }
+
+    private static VerifyAllEqualListElements verifyAllEqualListElements = new VerifyAllEqualListElements();
+
+    @Test
+    public void givenNotAllEqualList_whenUsingALoop_thenReturnFalse() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingALoop(notAllEqualList);
+
+        assertFalse(allEqual);
+    }
+
+    @Test
+    public void givenEmptyList_whenUsingALoop_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingALoop(emptyList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenAllEqualList_whenUsingALoop_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingALoop(allEqualList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenNotAllEqualList_whenUsingHashSet_thenReturnFalse() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingHashSet(notAllEqualList);
+
+        assertFalse(allEqual);
+    }
+
+    @Test
+    public void givenEmptyList_whenUsingHashSet_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingHashSet(emptyList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenAllEqualList_whenUsingHashSet_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingHashSet(allEqualList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenNotAllEqualList_whenUsingFrequency_thenReturnFalse() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingFrequency(notAllEqualList);
+
+        assertFalse(allEqual);
+    }
+
+    @Test
+    public void givenEmptyList_whenUsingFrequency_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingFrequency(emptyList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenAllEqualList_whenUsingFrequency_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingFrequency(allEqualList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenNotAllEqualList_whenUsingStream_thenReturnFalse() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingStream(notAllEqualList);
+
+        assertFalse(allEqual);
+    }
+
+    @Test
+    public void givenEmptyList_whenUsingStream_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingStream(emptyList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenAllEqualList_whenUsingStream_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingStream(allEqualList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenNotAllEqualList_whenUsingAnotherStream_thenReturnFalse() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualAnotherUsingStream(notAllEqualList);
+
+        assertFalse(allEqual);
+    }
+
+    @Test
+    public void givenEmptyList_whenUsingAnotherStream_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualAnotherUsingStream(emptyList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenAllEqualList_whenUsingAnotherStream_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualAnotherUsingStream(allEqualList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenNotAllEqualList_whenUsingGuava_thenReturnFalse() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingGuava(notAllEqualList);
+
+        assertFalse(allEqual);
+    }
+
+    @Test
+    public void givenEmptyList_whenUsingGuava_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingGuava(emptyList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenAllEqualList_whenUsingGuava_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingGuava(allEqualList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenNotAllEqualList_whenUsingApacheCommon_thenReturnFalse() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingApacheCommon(notAllEqualList);
+
+        assertFalse(allEqual);
+    }
+
+    @Test
+    public void givenEmptyList_whenUsingApacheCommon_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingApacheCommon(emptyList);
+
+        assertTrue(allEqual);
+    }
+
+    @Test
+    public void givenAllEqualList_whenUsingApacheCommon_thenReturnTrue() {
+        boolean allEqual = verifyAllEqualListElements.verifyAllEqualUsingApacheCommon(allEqualList);
+
+        assertTrue(allEqual);
+    }
+}