Merge origin/master

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-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-kotlin-2/.gitignore

@@ -0,0 +1,14 @@
+/bin/
+
+#ignore gradle
+.gradle/
+
+
+#ignore build and generated files
+build/
+node/
+out/
+
+#ignore installed node modules and package lock file
+node_modules/
+package-lock.json

core-kotlin-2/README.md

@@ -0,0 +1 @@
+## Relevant articles:

core-kotlin-2/build.gradle

@@ -0,0 +1,48 @@
+
+
+group 'com.baeldung.ktor'
+version '1.0-SNAPSHOT'
+
+
+buildscript {
+    ext.kotlin_version = '1.2.41'
+
+    repositories {
+        mavenCentral()
+    }
+    dependencies {
+
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+apply plugin: 'java'
+apply plugin: 'kotlin'
+apply plugin: 'application'
+
+mainClassName = 'APIServer.kt'
+
+sourceCompatibility = 1.8
+compileKotlin { kotlinOptions.jvmTarget = "1.8" }
+compileTestKotlin { kotlinOptions.jvmTarget = "1.8" }
+
+kotlin { experimental { coroutines "enable" } }
+
+repositories {
+    mavenCentral()
+    jcenter()
+    maven { url "https://dl.bintray.com/kotlin/ktor" }
+}
+sourceSets {
+    main{
+        kotlin{
+            srcDirs 'com/baeldung/ktor'
+        }
+    }
+
+}
+
+dependencies {
+    compile "ch.qos.logback:logback-classic:1.2.1"
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+}

core-kotlin-2/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip

core-kotlin-2/gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

core-kotlin-2/gradlew.bat

@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

core-kotlin-2/pom.xml

@@ -0,0 +1,16 @@
+<?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-kotlin-2</artifactId>
+    <name>core-kotlin-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-kotlin</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../parent-kotlin</relativePath>
+    </parent>
+
+</project>

core-kotlin-2/resources/logback.xml

@@ -0,0 +1,11 @@
+<configuration>
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <encoder>
+      <pattern>%d{YYYY-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+    </encoder>
+  </appender>
+
+  <root level="INFO">
+    <appender-ref ref="STDOUT"/>
+  </root>
+</configuration>

core-kotlin-2/settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'KtorWithKotlin'
+

core-kotlin-2/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

core-kotlin-2/src/test/resources/Kotlin.in

@@ -0,0 +1,5 @@
+Hello to Kotlin. Its:
+1. Concise
+2. Safe
+3. Interoperable
+4. Tool-friendly

core-kotlin-2/src/test/resources/Kotlin.out

@@ -0,0 +1,2 @@
+Kotlin
+Concise, Safe, Interoperable, Tool-friendly

core-kotlin/src/main/kotlin/com/baeldung/static/ConsoleUtils.kt

@@ -0,0 +1,10 @@
+package com.baeldung.static
+
+class ConsoleUtils {
+    companion object {
+        @JvmStatic
+        fun debug(debugMessage : String) {
+            println("[DEBUG] $debugMessage")
+        }
+    }
+}

core-kotlin/src/main/kotlin/com/baeldung/static/LoggingUtils.kt

@@ -0,0 +1,5 @@
+package com.baeldung.static
+
+fun debug(debugMessage : String) {
+    println("[DEBUG] $debugMessage")
+}

core-kotlin/src/test/kotlin/com/baeldung/static/ConsoleUtilsUnitTest.kt

@@ -0,0 +1,10 @@
+package com.baeldung.static
+
+import org.junit.Test
+
+class ConsoleUtilsUnitTest {
+    @Test
+    fun givenAStaticMethod_whenCalled_thenNoErrorIsThrown() {
+        ConsoleUtils.debug("test message")
+    }
+}

core-kotlin/src/test/kotlin/com/baeldung/static/LoggingUtilsUnitTest.kt

@@ -0,0 +1,10 @@
+package com.baeldung.static
+
+import org.junit.Test
+
+class LoggingUtilsUnitTest {
+    @Test
+    fun givenAPackageMethod_whenCalled_thenNoErrorIsThrown() {
+        debug("test message")
+    }
+}