Merge branch 'master' into BAEL-3287

2020-06-03 12:59:30 +04:30
parent a1f8f90bd8 d34fe14d61
commit 19f75cc1d2
139 changed files with 3200 additions and 720 deletions
@@ -12,3 +12,4 @@ This module contains articles about core Java features that have been introduced
 - [Introduction to Java 9 StackWalking API](https://www.baeldung.com/java-9-stackwalking-api)
 - [Java 9 Platform Logging API](https://www.baeldung.com/java-9-logging-api)
 - [Java 9 Reactive Streams](https://www.baeldung.com/java-9-reactive-streams)
+- [Multi-Release JAR Files with Maven](https://www.baeldung.com/maven-multi-release-jars)
@@ -33,8 +33,104 @@
            <version>${junit.platform.version}</version>
            <scope>test</scope>
        </dependency>
+        <dependency>
+            <groupId>org.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>${awaitility.version}</version>
+            <scope>test</scope>
+        </dependency>
    </dependencies>
-
+    <profiles>
+        <profile>
+            <id>incubator-features</id>
+            <build>
+                <finalName>core-java-9-new-features</finalName>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-compiler-plugin</artifactId>
+                        <version>${maven-compiler-plugin.version}</version>
+                        <configuration>
+                            <source>${maven.compiler.source}</source>
+                            <target>${maven.compiler.target}</target>
+                            <compilerArgument>--add-modules=jdk.incubator.httpclient</compilerArgument>
+                        </configuration>
+                    </plugin>
+                    <plugin>
+                        <artifactId>maven-surefire-plugin</artifactId>
+                        <configuration>
+                            <argLine>--add-modules=jdk.incubator.httpclient</argLine>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+        <profile>
+            <id>mrjar-generation</id>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-compiler-plugin</artifactId>
+                        <executions>
+                            <execution>
+                                <id>compile-java-8</id>
+                                <goals>
+                                    <goal>compile</goal>
+                                </goals>
+                                <configuration>
+                                    <source>1.8</source>
+                                    <target>1.8</target>
+                                    <compileSourceRoots>
+                                        <compileSourceRoot>${project.basedir}/src/main/java8</compileSourceRoot>
+                                    </compileSourceRoots>
+                                </configuration>
+                            </execution>
+                            <execution>
+                                <id>compile-java-9</id>
+                                <phase>compile</phase>
+                                <goals>
+                                    <goal>compile</goal>
+                                </goals>
+                                <configuration>
+                                    <release>9</release>
+                                    <compileSourceRoots>
+                                        <compileSourceRoot>${project.basedir}/src/main/java9</compileSourceRoot>
+                                    </compileSourceRoots>
+                                    <outputDirectory>${project.build.outputDirectory}/META-INF/versions/9</outputDirectory>
+                                </configuration>
+                            </execution>
+                            <execution>
+                                <id>default-testCompile</id>
+                                <phase>test-compile</phase>
+                                <goals>
+                                    <goal>testCompile</goal>
+                                </goals>
+                                <configuration>
+                                    <skip>true</skip>
+                                </configuration>
+                            </execution>
+                        </executions>
+                    </plugin>
+                    <plugin>
+                        <groupId>org.apache.maven.plugins</groupId>
+                        <artifactId>maven-jar-plugin</artifactId>
+                        <version>${maven-jar-plugin.version}</version>
+                        <configuration>
+                            <archive>
+                                <manifestEntries>
+                                    <Multi-Release>true</Multi-Release>
+                                </manifestEntries>
+                                <manifest>
+                                    <mainClass>com.baeldung.multireleaseapp.App</mainClass>
+                                </manifest>
+                            </archive>
+                        </configuration>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+    </profiles>
    <build>
        <finalName>core-java-9-new-features</finalName>
        <plugins>
@@ -61,8 +157,10 @@
        <!-- testing -->
        <assertj.version>3.10.0</assertj.version>
        <junit.platform.version>1.2.0</junit.platform.version>
+        <awaitility.version>4.0.2</awaitility.version>
        <maven.compiler.source>1.9</maven.compiler.source>
        <maven.compiler.target>1.9</maven.compiler.target>
+        <maven-jar-plugin.version>3.2.0</maven-jar-plugin.version>
        <rxjava.version>3.0.0</rxjava.version>
    </properties>

@@ -0,0 +1,14 @@
+package com.baeldung.multireleaseapp;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class App {
+
+    private static final Logger logger = LoggerFactory.getLogger(App.class);
+
+    public static void main(String[] args) {
+        logger.info(String.format("Running on %s", new DefaultVersion().version()));
+    }
+
+}
@@ -0,0 +1,9 @@
+package com.baeldung.multireleaseapp;
+
+public class DefaultVersion implements Version {
+
+    @Override
+    public String version() {
+        return System.getProperty("java.version");
+    }
+}
@@ -0,0 +1,5 @@
+package com.baeldung.multireleaseapp;
+
+interface Version {
+    public String version();
+}
@@ -0,0 +1,9 @@
+package com.baeldung.multireleaseapp;
+
+public class DefaultVersion implements Version {
+
+    @Override
+    public String version() {
+        return Runtime.version().toString();
+    }
+}
@@ -24,7 +24,7 @@ import static org.junit.Assert.assertThat;
 /**
 * Created by adam.
 */
-public class HttpClientTest {
+public class HttpClientIntegrationTest {

    @Test
    public void shouldReturnSampleDataContentWhenConnectViaSystemProxy() throws IOException, InterruptedException, URISyntaxException {
@@ -55,7 +55,7 @@ public class HttpClientTest {
            .send(request, HttpResponse.BodyHandler.asString());

        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_MOVED_PERM));
-        assertThat(response.body(), containsString("https://stackoverflow.com/"));
+        assertThat(response.body(), containsString(""));
    }

    @Test
@@ -22,7 +22,7 @@ import static org.junit.Assert.assertThat;
 /**
 * Created by adam.
 */
-public class HttpRequestTest {
+public class HttpRequestIntegrationTest {

    @Test
    public void shouldReturnStatusOKWhenSendGetRequest() throws IOException, InterruptedException, URISyntaxException {
@@ -18,7 +18,7 @@ import static org.junit.Assert.assertThat;
 /**
 * Created by adam.
 */
-public class HttpResponseTest {
+public class HttpResponseIntegrationTest {

    @Test
    public void shouldReturnStatusOKWhenSendGetRequest() throws IOException, InterruptedException, URISyntaxException {
@@ -5,10 +5,12 @@ import org.junit.Test;

 import java.util.List;
 import java.util.concurrent.SubmissionPublisher;
+import java.util.concurrent.TimeUnit;

-import static org.assertj.core.api.Java6Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.awaitility.Awaitility.await;

-public class ReactiveStreamsTest {
+public class ReactiveStreamsUnitTest {

    @Test
    public void givenPublisher_whenSubscribeToIt_thenShouldConsumeAllElements() throws InterruptedException {
@@ -25,7 +27,7 @@ public class ReactiveStreamsTest {

        //then

-        await().atMost(1000, TimeUnit.MILLISECONDS).until(
+        await().atMost(1000, TimeUnit.MILLISECONDS).untilAsserted(
                () -> assertThat(subscriber.consumedElements).containsExactlyElementsOf(items)
        );
    }
@@ -46,7 +48,7 @@ public class ReactiveStreamsTest {
        publisher.close();

        //then
-        await().atMost(1000, TimeUnit.MILLISECONDS).until(
+        await().atMost(1000, TimeUnit.MILLISECONDS).untilAsserted(
                () -> assertThat(subscriber.consumedElements).containsExactlyElementsOf(expectedResult)
        );
    }
@@ -66,7 +68,7 @@ public class ReactiveStreamsTest {
        publisher.close();

        //then
-        await().atMost(1000, TimeUnit.MILLISECONDS).until(
+        await().atMost(1000, TimeUnit.MILLISECONDS).untilAsserted(
                () -> assertThat(subscriber.consumedElements).containsExactlyElementsOf(expected)
        );
    }
@@ -7,7 +7,7 @@ import java.lang.invoke.VarHandle;

 import static org.assertj.core.api.Assertions.assertThat;

-public class VariableHandlesTest {
+public class VariableHandlesUnitTest {

    public int publicTestVariable = 1;
    private int privateTestVariable = 1;
@@ -20,22 +20,22 @@ public class VariableHandlesTest {
    public void whenVariableHandleForPublicVariableIsCreated_ThenItIsInitializedProperly() throws NoSuchFieldException, IllegalAccessException {
        VarHandle publicIntHandle = MethodHandles
          .lookup()
-          .in(VariableHandlesTest.class)
-          .findVarHandle(VariableHandlesTest.class, "publicTestVariable", int.class);
+          .in(VariableHandlesUnitTest.class)
+          .findVarHandle(VariableHandlesUnitTest.class, "publicTestVariable", int.class);

        assertThat(publicIntHandle.coordinateTypes().size() == 1);
-        assertThat(publicIntHandle.coordinateTypes().get(0) == VariableHandles.class);
+        assertThat(publicIntHandle.coordinateTypes().get(0) == VariableHandlesUnitTest.class);

    }

    @Test
    public void whenVariableHandleForPrivateVariableIsCreated_ThenItIsInitializedProperly() throws NoSuchFieldException, IllegalAccessException {
        VarHandle privateIntHandle = MethodHandles
-          .privateLookupIn(VariableHandlesTest.class, MethodHandles.lookup())
-          .findVarHandle(VariableHandlesTest.class, "privateTestVariable", int.class);
+          .privateLookupIn(VariableHandlesUnitTest.class, MethodHandles.lookup())
+          .findVarHandle(VariableHandlesUnitTest.class, "privateTestVariable", int.class);

        assertThat(privateIntHandle.coordinateTypes().size() == 1);
-        assertThat(privateIntHandle.coordinateTypes().get(0) == VariableHandlesTest.class);
+        assertThat(privateIntHandle.coordinateTypes().get(0) == VariableHandlesUnitTest.class);

    }

@@ -52,8 +52,8 @@ public class VariableHandlesTest {
    public void givenVarHandle_whenGetIsInvoked_ThenValueOfVariableIsReturned() throws NoSuchFieldException, IllegalAccessException {
        VarHandle publicIntHandle = MethodHandles
          .lookup()
-          .in(VariableHandlesTest.class)
-          .findVarHandle(VariableHandlesTest.class, "publicTestVariable", int.class);
+          .in(VariableHandlesUnitTest.class)
+          .findVarHandle(VariableHandlesUnitTest.class, "publicTestVariable", int.class);

        assertThat((int) publicIntHandle.get(this) == 1);
    }
@@ -62,8 +62,8 @@ public class VariableHandlesTest {
    public void givenVarHandle_whenSetIsInvoked_ThenValueOfVariableIsChanged() throws NoSuchFieldException, IllegalAccessException {
        VarHandle publicIntHandle = MethodHandles
          .lookup()
-          .in(VariableHandlesTest.class)
-          .findVarHandle(VariableHandlesTest.class, "variableToSet", int.class);
+          .in(VariableHandlesUnitTest.class)
+          .findVarHandle(VariableHandlesUnitTest.class, "variableToSet", int.class);
        publicIntHandle.set(this, 15);

        assertThat((int) publicIntHandle.get(this) == 15);
@@ -73,8 +73,8 @@ public class VariableHandlesTest {
    public void givenVarHandle_whenCompareAndSetIsInvoked_ThenValueOfVariableIsChanged() throws NoSuchFieldException, IllegalAccessException {
        VarHandle publicIntHandle = MethodHandles
          .lookup()
-          .in(VariableHandlesTest.class)
-          .findVarHandle(VariableHandlesTest.class, "variableToCompareAndSet", int.class);
+          .in(VariableHandlesUnitTest.class)
+          .findVarHandle(VariableHandlesUnitTest.class, "variableToCompareAndSet", int.class);
        publicIntHandle.compareAndSet(this, 1, 100);

        assertThat((int) publicIntHandle.get(this) == 100);
@@ -84,8 +84,8 @@ public class VariableHandlesTest {
    public void givenVarHandle_whenGetAndAddIsInvoked_ThenValueOfVariableIsChanged() throws NoSuchFieldException, IllegalAccessException {
        VarHandle publicIntHandle = MethodHandles
          .lookup()
-          .in(VariableHandlesTest.class)
-          .findVarHandle(VariableHandlesTest.class, "variableToGetAndAdd", int.class);
+          .in(VariableHandlesUnitTest.class)
+          .findVarHandle(VariableHandlesUnitTest.class, "variableToGetAndAdd", int.class);
        int before = (int) publicIntHandle.getAndAdd(this, 200);

        assertThat(before == 0);
@@ -96,8 +96,8 @@ public class VariableHandlesTest {
    public void givenVarHandle_whenGetAndBitwiseOrIsInvoked_ThenValueOfVariableIsChanged() throws NoSuchFieldException, IllegalAccessException {
        VarHandle publicIntHandle = MethodHandles
          .lookup()
-          .in(VariableHandlesTest.class)
-          .findVarHandle(VariableHandlesTest.class, "variableToBitwiseOr", byte.class);
+          .in(VariableHandlesUnitTest.class)
+          .findVarHandle(VariableHandlesUnitTest.class, "variableToBitwiseOr", byte.class);
        byte before = (byte) publicIntHandle.getAndBitwiseOr(this, (byte) 127);

        assertThat(before == 0);
@@ -5,4 +5,5 @@ This module contains articles about core Java input/output(IO) conversions.
 ### Relevant Articles:
 - [Java InputStream to String](https://www.baeldung.com/convert-input-stream-to-string)
 - [Java – Write an InputStream to a File](https://www.baeldung.com/convert-input-stream-to-a-file)
+- [Converting a BufferedReader to a JSONObject](https://www.baeldung.com/java-bufferedreader-to-jsonobject)
 - More articles: [[<-- prev]](/core-java-modules/core-java-io-conversions)
@@ -21,6 +21,11 @@
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>
+        <dependency>
+            <groupId>org.json</groupId>
+            <artifactId>json</artifactId>
+            <version>20200518</version>
+        </dependency>
    </dependencies>

    <build>
@@ -0,0 +1,48 @@
+package com.baeldung.bufferedreadertojsonobject;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+
+import org.json.JSONObject;
+import org.json.JSONTokener;
+import org.junit.Test;
+
+public class JavaBufferedReaderToJSONObjectUnitTest {
+
+    @Test
+    public void givenValidJson_whenUsingBufferedReader_thenJSONTokenerConverts() {
+        byte[] b = "{ \"name\" : \"John\", \"age\" : 18 }".getBytes(StandardCharsets.UTF_8);
+        InputStream is = new ByteArrayInputStream(b);
+        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(is));
+        JSONTokener tokener = new JSONTokener(bufferedReader);
+        JSONObject json = new JSONObject(tokener);
+
+        assertNotNull(json);
+        assertEquals("John", json.get("name"));
+        assertEquals(18, json.get("age"));
+    }
+
+    @Test
+    public void givenValidJson_whenUsingString_thenJSONObjectConverts() throws IOException {
+        byte[] b = "{ \"name\" : \"John\", \"age\" : 18 }".getBytes(StandardCharsets.UTF_8);
+        InputStream is = new ByteArrayInputStream(b);
+        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(is));
+        StringBuilder sb = new StringBuilder();
+        String line;
+        while ((line = bufferedReader.readLine()) != null) {
+            sb.append(line);
+        }
+        JSONObject json = new JSONObject(sb.toString());
+
+        assertNotNull(json);
+        assertEquals("John", json.get("name"));
+        assertEquals(18, json.get("age"));
+    }
+}
@@ -0,0 +1,40 @@
+package com.baeldung.error.oom;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+import org.junit.jupiter.api.Test;
+
+public class ExecutorServiceUnitTest {
+
+    @Test
+    public void givenAnExecutorService_WhenMoreTasksSubmitted_ThenAdditionalTasksWait() {
+
+        // Given
+        int noOfThreads = 5;
+        ExecutorService executorService = Executors.newFixedThreadPool(noOfThreads);
+
+        Runnable runnableTask = () -> {
+            try {
+                TimeUnit.HOURS.sleep(1);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        };
+
+        // When
+        IntStream.rangeClosed(1, 10)
+            .forEach(i -> executorService.submit(runnableTask));
+
+        // Then
+        assertThat(((ThreadPoolExecutor) executorService).getQueue()
+            .size(), is(equalTo(5)));
+    }
+}
@@ -0,0 +1,36 @@
+package com.baeldung.inttoenum;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public enum PizzaStatus {
+    ORDERED(5),
+    READY(2),
+    DELIVERED(0);
+
+    private int timeToDelivery;
+
+    PizzaStatus(int timeToDelivery) {
+        this.timeToDelivery = timeToDelivery;
+    }
+
+    public int getTimeToDelivery() {
+        return timeToDelivery;
+    }
+
+    private static Map<Integer, PizzaStatus> timeToDeliveryToEnumValuesMapping = new HashMap<>();
+
+    static {
+        PizzaStatus[] pizzaStatuses = PizzaStatus.values();
+        for (int pizzaStatusIndex = 0; pizzaStatusIndex < pizzaStatuses.length; pizzaStatusIndex++) {
+            timeToDeliveryToEnumValuesMapping.put(
+                pizzaStatuses[pizzaStatusIndex].getTimeToDelivery(),
+                pizzaStatuses[pizzaStatusIndex]
+            );
+        }
+    }
+
+    public static PizzaStatus castIntToEnum(int timeToDelivery) {
+        return timeToDeliveryToEnumValuesMapping.get(timeToDelivery);
+    }
+}
@@ -0,0 +1,27 @@
+package com.baeldung.inttoenum;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class IntToEnumUnitTest {
+
+    @Test
+    public void whenIntToEnumUsingValuesMethod_thenReturnEnumObject() {
+        int timeToDeliveryForOrderedPizzaStatus = 5;
+        PizzaStatus[] pizzaStatuses = PizzaStatus.values();
+        PizzaStatus pizzaOrderedStatus = null;
+        for (int pizzaStatusIndex = 0; pizzaStatusIndex < pizzaStatuses.length; pizzaStatusIndex++) {
+            if (pizzaStatuses[pizzaStatusIndex].getTimeToDelivery() == timeToDeliveryForOrderedPizzaStatus) {
+                pizzaOrderedStatus = pizzaStatuses[pizzaStatusIndex];
+            }
+        }
+        assertEquals(pizzaOrderedStatus, PizzaStatus.ORDERED);
+    }
+
+    @Test
+    public void whenIntToEnumUsingMap_thenReturnEnumObject() {
+        int timeToDeliveryForOrderedPizzaStatus = 5;
+        assertEquals(PizzaStatus.castIntToEnum(timeToDeliveryForOrderedPizzaStatus), PizzaStatus.ORDERED);
+    }
+}
@@ -0,0 +1,18 @@
+package com.baeldung.supertype;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+
+public abstract class TypeReference<T> {
+
+    private final Type type;
+
+    public TypeReference() {
+        Type superclass = getClass().getGenericSuperclass();
+        type = ((ParameterizedType) superclass).getActualTypeArguments()[0];
+    }
+
+    public Type getType() {
+        return type;
+    }
+}
@@ -0,0 +1,24 @@
+package com.baeldung.supertype;
+
+import org.junit.Test;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+public class TypeReferenceUnitTest {
+
+    @Test
+    public void givenGenericToken_whenUsingSuperTypeToken_thenPreservesTheTypeInfo() {
+        TypeReference<Map<String, Integer>> token = new TypeReference<Map<String, Integer>>() {};
+        Type type = token.getType();
+
+        assertEquals("java.util.Map<java.lang.String, java.lang.Integer>", type.getTypeName());
+
+        Type[] typeArguments = ((ParameterizedType) type).getActualTypeArguments();
+        assertEquals("java.lang.String", typeArguments[0].getTypeName());
+        assertEquals("java.lang.Integer", typeArguments[1].getTypeName());
+    }
+}