Merge branch 'master' into BAEL-16633

core-java-modules/core-java-9-jigsaw/README.md

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+## Core Java 9
+
+This module contains articles about Project Jigsaw and the Java Platform Module System (JPMS), introduced with Java 9.
+
+### Relevant Articles:
+
+- [Introduction to Project Jigsaw](http://www.baeldung.com/project-jigsaw-java-modularity)
+- [A Guide to Java 9 Modularity](https://www.baeldung.com/java-9-modularity)
+- [Java 9 java.lang.Module API](https://www.baeldung.com/java-9-module-api)
+
+

core-java-modules/core-java-9-jigsaw/compile-simple-modules.sh

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+#!/usr/bin/env bash
+javac -d outDir --module-source-path src/simple-modules $(find src/simple-modules -name "*.java")

core-java-modules/core-java-9-jigsaw/compile-student-client.bat

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+javac --module-path mods -d mods/com.baeldung.student.client^
+ src/modules/com.baeldung.student.client/module-info.java^
+ src/modules/com.baeldung.student.client/com/baeldung/student/client/StudentClient.java

core-java-modules/core-java-9-jigsaw/compile-student-model.bat

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+javac -d mods/com.baeldung.student.model src/modules/com.baeldung.student.model/module-info.java^
+	src/modules/com.baeldung.student.model/com/baeldung/student/model/Student.java

core-java-modules/core-java-9-jigsaw/compile-student-service-dbimpl.bat

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+javac --module-path mods -d mods/com.baeldung.student.service.dbimpl^
+ src/modules/com.baeldung.student.service.dbimpl/module-info.java^
+ src/modules/com.baeldung.student.service.dbimpl/com/baeldung/student/service/dbimpl/StudentDbService.java

core-java-modules/core-java-9-jigsaw/compile-student-service.bat

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+javac --module-path mods -d mods/com.baeldung.student.service^
+ src/modules/com.baeldung.student.service/module-info.java^
+ src/modules/com.baeldung.student.service/com/baeldung/student/service/StudentService.java

core-java-modules/core-java-9-jigsaw/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-java-9-jigsaw</artifactId>
+    <version>0.2-SNAPSHOT</version>
+    <name>core-java-9</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+    <build>
+        <finalName>core-java-9-jigsaw</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>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <maven.compiler.source>1.9</maven.compiler.source>
+        <maven.compiler.target>1.9</maven.compiler.target>
+    </properties>
+
+</project>

core-java-modules/core-java-9-jigsaw/run-simple-module-app.sh

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+#!/usr/bin/env bash
+java --module-path outDir -m main.app/com.baeldung.modules.main.MainApp

core-java-modules/core-java-9-jigsaw/run-student-client.bat

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+java --module-path mods -m com.baeldung.student.client/com.baeldung.student.client.StudentClient

core-java-modules/core-java-9-jigsaw/run-student-client.sh

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+java --module-path mods -m com.baeldung.student.client/com.baeldung.student.client.StudentClient

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.client/com/baeldung/student/client/StudentClient.java

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+package com.baeldung.student.client;
+
+import com.baeldung.student.service.StudentService;
+import com.baeldung.student.service.dbimpl.StudentDbService;
+import com.baeldung.student.model.Student;
+
+public class StudentClient {
+
+    public static void main(String[] args) {
+        StudentService service = new StudentDbService();
+        service.create(new Student());
+        service.read("17SS0001");
+        service.update(new Student());
+        service.delete("17SS0001");
+    }
+}

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.client/module-info.java

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+module com.baeldung.student.client{
+    requires com.baeldung.student.service.dbimpl;
+}

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.model/com/baeldung/student/model/Student.java

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+package com.baeldung.student.model;
+
+import java.util.Date;
+
+public class Student {
+    private String registrationId;
+
+    public String getRegistrationId() {
+        return registrationId;
+    }
+
+    public void setRegistrationId(String registrationId) {
+        this.registrationId = registrationId;
+    }
+}

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.model/module-info.java

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+module com.baeldung.student.model{
+    exports com.baeldung.student.model;
+}

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.service.dbimpl/com/baeldung/student/service/dbimpl/StudentDbService.java

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+package com.baeldung.student.service.dbimpl;
+
+import com.baeldung.student.service.StudentService;
+import com.baeldung.student.model.Student;
+import java.util.logging.*;
+
+public class StudentDbService implements StudentService {
+
+    private static Logger logger = Logger.getLogger("StudentDbService");
+
+    public String create(Student student) {
+        logger.log(Level.INFO, "Creating student in DB...");
+        return student.getRegistrationId();
+    }
+
+    public Student read(String registrationId) {
+        logger.log(Level.INFO, "Reading student from DB...");
+        return new Student();
+    }
+
+    public Student update(Student student) {
+        logger.log(Level.INFO, "Updating sutdent in DB...");
+        return student;
+    }
+
+    public String delete(String registrationId) {
+        logger.log(Level.INFO, "Deleteing sutdent in DB...");
+        return registrationId;
+    }
+}

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.service.dbimpl/module-info.java

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+module com.baeldung.student.service.dbimpl{
+    requires transitive com.baeldung.student.service;
+    exports com.baeldung.student.service.dbimpl;
+    requires java.logging;
+}

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.service/com/baeldung/student/service/StudentService.java

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+package com.baeldung.student.service;
+
+import com.baeldung.student.model.Student;
+
+public interface StudentService {
+
+    public String create(Student student);
+
+    public Student read(String registrationId);
+
+    public Student update(Student student);
+
+    public String delete(String registrationId);
+}

core-java-modules/core-java-9-jigsaw/src/modules/com.baeldung.student.service/module-info.java

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+module com.baeldung.student.service{
+    requires transitive com.baeldung.student.model;
+    exports com.baeldung.student.service;
+}

core-java-modules/core-java-9-jigsaw/src/simple-modules/hello.modules/com/baeldung/modules/hello/HelloInterface.java

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+package com.baeldung.modules.hello;
+
+public interface HelloInterface {
+    public void sayHello();
+}

core-java-modules/core-java-9-jigsaw/src/simple-modules/hello.modules/com/baeldung/modules/hello/HelloModules.java

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+package com.baeldung.modules.hello;
+
+public class HelloModules implements HelloInterface {
+    public static void doSomething() {
+        System.out.println("Hello, Modules!");
+    }
+
+    public void sayHello() {
+        System.out.println("Hello!");
+    }
+}

core-java-modules/core-java-9-jigsaw/src/simple-modules/hello.modules/module-info.java

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+module hello.modules {
+    exports com.baeldung.modules.hello;
+    provides com.baeldung.modules.hello.HelloInterface with com.baeldung.modules.hello.HelloModules;
+}

core-java-modules/core-java-9-jigsaw/src/simple-modules/main.app/com/baeldung/modules/main/MainApp.java

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+package com.baeldung.modules.main;
+
+import com.baeldung.modules.hello.HelloModules;
+
+public class MainApp {
+    public static void main(String[] args) {
+        HelloModules.doSomething();
+
+        HelloModules module = new HelloModules();
+        module.sayHello();
+    }
+}

core-java-modules/core-java-9-jigsaw/src/simple-modules/main.app/module-info.java

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+module main.app {
+    requires hello.modules;
+    uses com.baeldung.modules.hello.HelloInterface;
+}

core-java-modules/core-java-9-jigsaw/src/test/java/com/baeldung/java9/modules/ModuleAPIUnitTest.java

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+package com.baeldung.java9.modules;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.collection.IsEmptyCollection.empty;
+import static org.junit.Assert.*;
+
+import java.lang.module.ModuleDescriptor;
+import java.lang.module.ModuleDescriptor.*;
+import java.sql.Date;
+import java.sql.Driver;
+import java.util.HashMap;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class ModuleAPIUnitTest {
+
+    public static final String JAVA_BASE_MODULE_NAME = "java.base";
+
+    private Module javaBaseModule;
+    private Module javaSqlModule;
+    private Module module;
+
+    @Before
+    public void setUp() {
+        Class<HashMap> hashMapClass = HashMap.class;
+        javaBaseModule = hashMapClass.getModule();
+
+        Class<Date> dateClass = Date.class;
+        javaSqlModule = dateClass.getModule();
+
+        Class<Person> personClass = Person.class;
+        module = personClass.getModule();
+    }
+
+    @Test
+    public void whenCheckingIfNamed_thenModuleIsNamed() {
+        assertThat(javaBaseModule.isNamed(), is(true));
+        assertThat(javaBaseModule.getName(), is(JAVA_BASE_MODULE_NAME));
+    }
+
+    @Test
+    public void whenCheckingIfNamed_thenModuleIsUnnamed() {
+        assertThat(module.isNamed(), is(false));
+        assertThat(module.getName(), is(nullValue()));
+    }
+
+    @Test
+    public void whenExtractingPackagesContainedInAModule_thenModuleContainsOnlyFewOfThem() {
+        assertTrue(javaBaseModule.getPackages().contains("java.lang.annotation"));
+        assertFalse(javaBaseModule.getPackages().contains("java.sql"));
+    }
+
+    @Test
+    public void whenRetrievingClassLoader_thenClassLoaderIsReturned() {
+        assertThat(
+          module.getClassLoader().getClass().getName(),
+          is("jdk.internal.loader.ClassLoaders$AppClassLoader")
+        );
+    }
+
+    @Test
+    public void whenGettingAnnotationsPresentOnAModule_thenNoAnnotationsArePresent() {
+        assertThat(javaBaseModule.getAnnotations().length, is(0));
+    }
+
+    @Test
+    public void whenGettingLayerOfAModule_thenModuleLayerInformationAreAvailable() {
+        ModuleLayer javaBaseModuleLayer = javaBaseModule.getLayer();
+
+        assertTrue(javaBaseModuleLayer.configuration().findModule(JAVA_BASE_MODULE_NAME).isPresent());
+        assertThat(javaBaseModuleLayer.configuration().modules().size(), is(78));
+        assertTrue(javaBaseModuleLayer.parents().get(0).configuration().parents().isEmpty());
+    }
+
+    @Test
+    public void whenRetrievingModuleDescriptor_thenTypeOfModuleIsInferred() {
+        ModuleDescriptor javaBaseModuleDescriptor = javaBaseModule.getDescriptor();
+        ModuleDescriptor javaSqlModuleDescriptor = javaSqlModule.getDescriptor();
+
+        assertFalse(javaBaseModuleDescriptor.isAutomatic());
+        assertFalse(javaBaseModuleDescriptor.isOpen());
+        assertFalse(javaSqlModuleDescriptor.isAutomatic());
+        assertFalse(javaSqlModuleDescriptor.isOpen());
+    }
+
+    @Test
+    public void givenModuleName_whenBuildingModuleDescriptor_thenBuilt() {
+        Builder moduleBuilder = ModuleDescriptor.newModule("baeldung.base");
+
+        ModuleDescriptor moduleDescriptor = moduleBuilder.build();
+
+        assertThat(moduleDescriptor.name(), is("baeldung.base"));
+    }
+
+    @Test
+    public void givenModules_whenAccessingModuleDescriptorRequires_thenRequiresAreReturned() {
+        Set<Requires> javaBaseRequires = javaBaseModule.getDescriptor().requires();
+        Set<Requires> javaSqlRequires = javaSqlModule.getDescriptor().requires();
+
+        Set<String> javaSqlRequiresNames = javaSqlRequires.stream()
+          .map(Requires::name)
+          .collect(Collectors.toSet());
+
+        assertThat(javaBaseRequires, empty());
+        assertThat(javaSqlRequires.size(), is(3));
+        assertThat(javaSqlRequiresNames, containsInAnyOrder("java.base", "java.xml", "java.logging"));
+    }
+
+    @Test
+    public void givenModules_whenAccessingModuleDescriptorProvides_thenProvidesAreReturned() {
+        Set<Provides> javaBaseProvides = javaBaseModule.getDescriptor().provides();
+        Set<Provides> javaSqlProvides = javaSqlModule.getDescriptor().provides();
+
+        Set<String> javaBaseProvidesService = javaBaseProvides.stream()
+                .map(Provides::service)
+                .collect(Collectors.toSet());
+
+        assertThat(javaBaseProvidesService, contains("java.nio.file.spi.FileSystemProvider"));
+        assertThat(javaSqlProvides, empty());
+    }
+
+    @Test
+    public void givenModules_whenAccessingModuleDescriptorExports_thenExportsAreReturned() {
+        Set<Exports> javaBaseExports = javaBaseModule.getDescriptor().exports();
+        Set<Exports> javaSqlExports = javaSqlModule.getDescriptor().exports();
+
+        Set<String> javaSqlExportsSource = javaSqlExports.stream()
+          .map(Exports::source)
+          .collect(Collectors.toSet());
+
+        assertThat(javaBaseExports.size(), is(108));
+        assertThat(javaSqlExports.size(), is(3));
+        assertThat(javaSqlExportsSource, containsInAnyOrder("java.sql", "javax.transaction.xa", "javax.sql"));
+    }
+
+    @Test
+    public void givenModules_whenAccessingModuleDescriptorUses_thenUsesAreReturned() {
+        Set<String> javaBaseUses = javaBaseModule.getDescriptor().uses();
+        Set<String> javaSqlUses = javaSqlModule.getDescriptor().uses();
+
+        assertThat(javaBaseUses.size(), is(34));
+        assertThat(javaSqlUses, contains("java.sql.Driver"));
+    }
+
+    @Test
+    public void givenModules_whenAccessingModuleDescriptorOpen_thenOpenAreReturned() {
+        Set<Opens> javaBaseUses = javaBaseModule.getDescriptor().opens();
+        Set<Opens> javaSqlUses = javaSqlModule.getDescriptor().opens();
+
+        assertThat(javaBaseUses, empty());
+        assertThat(javaSqlUses, empty());
+    }
+
+    @Test
+    public void whenAddingReadsToAModule_thenModuleCanReadNewModule() {
+        Module updatedModule = module.addReads(javaSqlModule);
+
+        assertTrue(updatedModule.canRead(javaSqlModule));
+    }
+
+    @Test
+    public void whenExportingPackage_thenPackageIsExported() {
+        Module updatedModule = module.addExports("com.baeldung.java9.modules", javaSqlModule);
+
+        assertTrue(updatedModule.isExported("com.baeldung.java9.modules"));
+    }
+
+    @Test
+    public void whenOpeningAModulePackage_thenPackagedIsOpened() {
+        Module updatedModule = module.addOpens("com.baeldung.java9.modules", javaSqlModule);
+
+        assertTrue(updatedModule.isOpen("com.baeldung.java9.modules", javaSqlModule));
+    }
+
+    @Test
+    public void whenAddingUsesToModule_thenUsesIsAdded() {
+        Module updatedModule = module.addUses(Driver.class);
+
+        assertTrue(updatedModule.canUse(Driver.class));
+    }
+
+    private class Person {
+        private String name;
+
+        public Person(String name) {
+            this.name = name;
+        }
+
+        public String getName() {
+            return name;
+        }
+    }
+}