[BAEL-4204] JNA (#10113)

* [BAEL-4203] JNA

* [BAEL-4203] JNA

java-native/src/main/java/com/baeldung/jni/ExampleObjectsJNI.java

@@ -0,0 +1,19 @@
+package com.baeldung.jni;
+
+public class ExampleObjectsJNI {
+
+    static {
+        System.loadLibrary("native");
+    }
+    
+    public static void main(String[] args) {
+        ExampleObjectsJNI instance = new ExampleObjectsJNI();
+        UserData newUser = instance.createUser("John Doe", 450.67);
+        instance.printUserData(newUser);
+    }
+    
+    public native UserData createUser(String name, double balance);
+    
+    public native String printUserData(UserData user);
+
+}

java-native/src/main/java/com/baeldung/jni/ExampleParametersJNI.java

@@ -0,0 +1,20 @@
+package com.baeldung.jni;
+
+public class ExampleParametersJNI {
+
+    static {
+        System.loadLibrary("native");
+    }
+    
+    public static void main(String[] args) {  
+        System.out.println("Java: My full name: " + new ExampleParametersJNI().sayHelloToMe("Martin", false));
+        long sumFromNative = new ExampleParametersJNI().sumIntegers(456, 44);
+        System.out.println("Java: The sum coming from native code is: " + sumFromNative);
+    }
+    
+    // Declare another method sumIntegers that receives two integers and return a long with the sum
+    public native long sumIntegers(int first, int second);
+    
+    // Declare another method sayHelloToMe that receives the name and gender and returns the proper salutation
+    public native String sayHelloToMe(String name, boolean isFemale);
+}

java-native/src/main/java/com/baeldung/jni/HelloWorldJNI.java

@@ -0,0 +1,15 @@
+package com.baeldung.jni;
+
+public class HelloWorldJNI {
+
+    static {
+        System.loadLibrary("native");
+    }
+    
+    public static void main(String[] args) {
+        new HelloWorldJNI().sayHello();
+    }
+
+    // Declare a native method sayHello() that receives no arguments and returns void
+    public native String sayHello();
+}

java-native/src/main/java/com/baeldung/jni/UserData.java

@@ -0,0 +1,11 @@
+package com.baeldung.jni;
+
+public class UserData {
+    
+    public String name;
+    public double balance;
+    
+    public String getUserInfo() {
+        return "[name]=" + name + ", [balance]=" + balance;
+    }
+}