From 4cc3f3413c8c1d88d13ed7df0a27108cd14a1638 Mon Sep 17 00:00:00 2001
From: Alejandro Gervasio <alejandro.gervasio@gmail.com>
Date: Fri, 3 May 2019 00:45:12 -0300
Subject: [PATCH] Multimodule Maven Project using Java Modules (#6875)

* Initial Commit

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update pom.xml

* Update module-info.java

* Update module-info.java

* Update pom.xml

* Update pom.xml
---
 .../multimodulemavenproject/daomodule/pom.xml | 27 ++++++++
 .../main/java/com/baeldung/daomodule/Dao.java | 11 ++++
 .../daomodule/src/main/java/module-info.java  |  3 +
 .../entitymodule/pom.xml                      | 28 +++++++++
 .../java/com/baeldung/entitymodule/User.java  | 19 ++++++
 .../src/main/java/module-info.java            |  3 +
 .../mainappmodule/pom.xml                     | 45 ++++++++++++++
 .../baeldung/mainappmodule/Application.java   | 19 ++++++
 .../src/main/java/module-info.java            |  8 +++
 .../multimodulemavenproject/pom.xml           | 62 +++++++++++++++++++
 .../userdaomodule/pom.xml                     | 41 ++++++++++++
 .../com/baeldung/userdaomodule/UserDao.java   | 32 ++++++++++
 .../src/main/java/module-info.java            |  6 ++
 core-java-modules/pom.xml                     |  5 +-
 14 files changed, 307 insertions(+), 2 deletions(-)
 create mode 100644 core-java-modules/multimodulemavenproject/daomodule/pom.xml
 create mode 100644 core-java-modules/multimodulemavenproject/daomodule/src/main/java/com/baeldung/daomodule/Dao.java
 create mode 100644 core-java-modules/multimodulemavenproject/daomodule/src/main/java/module-info.java
 create mode 100644 core-java-modules/multimodulemavenproject/entitymodule/pom.xml
 create mode 100644 core-java-modules/multimodulemavenproject/entitymodule/src/main/java/com/baeldung/entitymodule/User.java
 create mode 100644 core-java-modules/multimodulemavenproject/entitymodule/src/main/java/module-info.java
 create mode 100644 core-java-modules/multimodulemavenproject/mainappmodule/pom.xml
 create mode 100644 core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/com/baeldung/mainappmodule/Application.java
 create mode 100644 core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/module-info.java
 create mode 100644 core-java-modules/multimodulemavenproject/pom.xml
 create mode 100644 core-java-modules/multimodulemavenproject/userdaomodule/pom.xml
 create mode 100644 core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/com/baeldung/userdaomodule/UserDao.java
 create mode 100644 core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/module-info.java

diff --git a/core-java-modules/multimodulemavenproject/daomodule/pom.xml b/core-java-modules/multimodulemavenproject/daomodule/pom.xml
new file mode 100644
index 0000000000..a260e15e6d
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/daomodule/pom.xml
@@ -0,0 +1,27 @@
+<?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>
+    <parent>
+        <groupId>com.baeldung.multimodulemavenproject</groupId>
+        <artifactId>multimodulemavenproject</artifactId>
+        <version>1.0</version>
+    </parent>
+    <groupId>com.baeldung.daomodule</groupId>
+    <artifactId>daomodule</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+    
+    <properties>
+        <maven.compiler.source>9</maven.compiler.source>
+        <maven.compiler.target>9</maven.compiler.target>
+    </properties>
+</project>
\ No newline at end of file
diff --git a/core-java-modules/multimodulemavenproject/daomodule/src/main/java/com/baeldung/daomodule/Dao.java b/core-java-modules/multimodulemavenproject/daomodule/src/main/java/com/baeldung/daomodule/Dao.java
new file mode 100644
index 0000000000..9568bae9d9
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/daomodule/src/main/java/com/baeldung/daomodule/Dao.java
@@ -0,0 +1,11 @@
+package com.baeldung.daomodule;
+import java.util.List;
+import java.util.Optional;
+
+public interface Dao<T> {
+
+    Optional<T> findById(int id);
+
+    List<T> findAll();
+
+}
diff --git a/core-java-modules/multimodulemavenproject/daomodule/src/main/java/module-info.java b/core-java-modules/multimodulemavenproject/daomodule/src/main/java/module-info.java
new file mode 100644
index 0000000000..20c51d316a
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/daomodule/src/main/java/module-info.java
@@ -0,0 +1,3 @@
+module com.baeldung.daomodule {
+    exports com.baeldung.daomodule;
+}
diff --git a/core-java-modules/multimodulemavenproject/entitymodule/pom.xml b/core-java-modules/multimodulemavenproject/entitymodule/pom.xml
new file mode 100644
index 0000000000..1fd672d03e
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/entitymodule/pom.xml
@@ -0,0 +1,28 @@
+<?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>
+    <parent>
+        <groupId>com.baeldung.multimodulemavenproject</groupId>
+        <artifactId>multimodulemavenproject</artifactId>
+        <version>1.0</version>
+    </parent>
+    <groupId>com.baeldung.entitymodule</groupId>
+    <artifactId>entitymodule</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+    
+     <properties>
+        <maven.compiler.source>9</maven.compiler.source>
+        <maven.compiler.target>9</maven.compiler.target>
+    </properties>
+    
+</project>
\ No newline at end of file
diff --git a/core-java-modules/multimodulemavenproject/entitymodule/src/main/java/com/baeldung/entitymodule/User.java b/core-java-modules/multimodulemavenproject/entitymodule/src/main/java/com/baeldung/entitymodule/User.java
new file mode 100644
index 0000000000..c025bffd87
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/entitymodule/src/main/java/com/baeldung/entitymodule/User.java
@@ -0,0 +1,19 @@
+package com.baeldung.entitymodule;
+
+public class User {
+
+    private final String name;
+
+    public User(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public String toString() {
+        return "User{" + "name=" + name + '}';
+    }
+}
\ No newline at end of file
diff --git a/core-java-modules/multimodulemavenproject/entitymodule/src/main/java/module-info.java b/core-java-modules/multimodulemavenproject/entitymodule/src/main/java/module-info.java
new file mode 100644
index 0000000000..b2c4553357
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/entitymodule/src/main/java/module-info.java
@@ -0,0 +1,3 @@
+module com.baeldung.entitymodule {
+    exports com.baeldung.entitymodule;
+}
diff --git a/core-java-modules/multimodulemavenproject/mainappmodule/pom.xml b/core-java-modules/multimodulemavenproject/mainappmodule/pom.xml
new file mode 100644
index 0000000000..26e6a15b1e
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/mainappmodule/pom.xml
@@ -0,0 +1,45 @@
+<?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>
+    <parent>
+        <groupId>com.baeldung.multimodulemavenproject</groupId>
+        <artifactId>multimodulemavenproject</artifactId>
+        <version>1.0</version>
+    </parent>
+    <groupId>com.baeldung.mainappmodule</groupId>
+    <artifactId>mainappmodule</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    
+    <dependencies>
+        <dependency>
+            <groupId>com.baeldung.entitymodule</groupId>
+            <artifactId>entitymodule</artifactId>
+            <version>1.0</version>
+        </dependency>
+        <dependency>
+            <groupId>com.baeldung.daomodule</groupId>
+            <artifactId>daomodule</artifactId>
+            <version>1.0</version>
+        </dependency>
+        <dependency>
+            <groupId>com.baeldung.userdaomodule</groupId>
+            <artifactId>userdaomodule</artifactId>
+            <version>1.0</version>
+        </dependency>
+    </dependencies>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+    
+    <properties>
+        <maven.compiler.source>9</maven.compiler.source>
+        <maven.compiler.target>9</maven.compiler.target>
+    </properties>
+</project>
\ No newline at end of file
diff --git a/core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/com/baeldung/mainappmodule/Application.java b/core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/com/baeldung/mainappmodule/Application.java
new file mode 100644
index 0000000000..cf0ba1d9bc
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/com/baeldung/mainappmodule/Application.java
@@ -0,0 +1,19 @@
+package com.baeldung.mainappmodule;
+
+import com.baeldung.daomodule.Dao;
+import com.baeldung.entitymodule.User;
+import com.baeldung.userdaomodule.UserDao;
+import java.util.HashMap;
+import java.util.Map;
+
+public class Application {
+    
+    public static void main(String args[]) {
+        Map<Integer, User> users = new HashMap<>();
+        users.put(1, new User("Julie"));
+        users.put(2, new User("David"));
+        Dao userDao = new UserDao(users);
+        userDao.findAll().forEach(System.out::println);
+    }
+    
+}
diff --git a/core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/module-info.java b/core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/module-info.java
new file mode 100644
index 0000000000..dd7620c7bf
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/mainappmodule/src/main/java/module-info.java
@@ -0,0 +1,8 @@
+module com.baeldung.mainppmodule {
+    
+    requires com.baeldung.entitymodule;
+    requires com.baeldung.daomodule;
+    requires com.baeldung.userdaomodule;
+    uses com.baeldung.userdaomodule.UserDao;
+    
+}
diff --git a/core-java-modules/multimodulemavenproject/pom.xml b/core-java-modules/multimodulemavenproject/pom.xml
new file mode 100644
index 0000000000..3d56f1356b
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/pom.xml
@@ -0,0 +1,62 @@
+<?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>
+    <groupId>com.baeldung.multimodulemavenproject</groupId>
+    <artifactId>multimodulemavenproject</artifactId>
+    <version>1.0</version>
+    <packaging>pom</packaging>
+    <name>multimodulemavenproject</name>
+    
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+    
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>junit</groupId>
+                <artifactId>junit</artifactId>
+                <version>4.12</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.assertj</groupId>
+                <artifactId>assertj-core</artifactId>
+                <version>3.12.2</version>
+                <scope>test</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+    
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>3.8.0</version>
+                    <configuration>
+                        <configuration>
+                            <source>1.9</source>
+                            <target>1.9</target>
+                        </configuration>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+    
+    <modules>
+        <module>entitymodule</module>
+        <module>daomodule</module>
+        <module>userdaomodule</module>
+        <module>mainappmodule</module>
+    </modules>
+    
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+</project>
diff --git a/core-java-modules/multimodulemavenproject/userdaomodule/pom.xml b/core-java-modules/multimodulemavenproject/userdaomodule/pom.xml
new file mode 100644
index 0000000000..63968452db
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/userdaomodule/pom.xml
@@ -0,0 +1,41 @@
+<?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>
+    <parent>
+        <groupId>com.baeldung.multimodulemavenproject</groupId>
+        <artifactId>multimodulemavenproject</artifactId>
+        <version>1.0</version>
+    </parent>
+    <groupId>com.baeldung.userdaomodule</groupId>
+    <artifactId>userdaomodule</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+    
+    <dependencies>
+        <dependency>
+            <groupId>com.baeldung.entitymodule</groupId>
+            <artifactId>entitymodule</artifactId>
+            <version>1.0</version>
+        </dependency>
+        <dependency>
+            <groupId>com.baeldung.daomodule</groupId>
+            <artifactId>daomodule</artifactId>
+            <version>1.0</version>
+        </dependency>
+    </dependencies>
+    
+    <properties>
+        <maven.compiler.source>9</maven.compiler.source>
+        <maven.compiler.target>9</maven.compiler.target>
+    </properties>
+    
+</project>
\ No newline at end of file
diff --git a/core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/com/baeldung/userdaomodule/UserDao.java b/core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/com/baeldung/userdaomodule/UserDao.java
new file mode 100644
index 0000000000..aba157b431
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/com/baeldung/userdaomodule/UserDao.java
@@ -0,0 +1,32 @@
+package com.baeldung.userdaomodule;
+
+import com.baeldung.daomodule.Dao;
+import com.baeldung.entitymodule.User;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+public class UserDao implements Dao<User> {
+
+    private final Map<Integer, User> users;
+
+    public UserDao() {
+        users = new HashMap<>();
+    }
+
+    public UserDao(Map<Integer, User> users) {
+        this.users = users;
+    }
+
+    @Override
+    public List<User> findAll() {
+        return new ArrayList<>(users.values());
+    }
+
+    @Override
+    public Optional<User> findById(int id) {
+        return Optional.ofNullable(users.get(id));
+    }
+}
\ No newline at end of file
diff --git a/core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/module-info.java b/core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/module-info.java
new file mode 100644
index 0000000000..6dd81dabe5
--- /dev/null
+++ b/core-java-modules/multimodulemavenproject/userdaomodule/src/main/java/module-info.java
@@ -0,0 +1,6 @@
+module com.baeldung.userdaomodule {
+    requires com.baeldung.entitymodule;
+    requires com.baeldung.daomodule;
+    provides com.baeldung.daomodule.Dao with com.baeldung.userdaomodule.UserDao;
+    exports com.baeldung.userdaomodule;
+}
diff --git a/core-java-modules/pom.xml b/core-java-modules/pom.xml
index ad49cceb9d..ed6a056448 100644
--- a/core-java-modules/pom.xml
+++ b/core-java-modules/pom.xml
@@ -2,6 +2,7 @@
 <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>
+    <groupId>com.baeldung.core-java-modules</groupId>
     <artifactId>core-java-modules</artifactId>
     <name>core-java-modules</name>
     <packaging>pom</packaging>
@@ -15,5 +16,5 @@
     <modules>
         <module>pre-jpms</module>
     </modules>
-
-</project>
\ No newline at end of file
+    
+</project>