default method Multiple Inheritance

spdpiyush · spdpiyush · commit 1bf925cd0836 · 2025-03-16T19:20:06.000+05:30
diff --git a/Modern-Java-Examples/src/com/learn/defaults/Client123.java b/Modern-Java-Examples/src/com/learn/defaults/Client123.java
@@ -0,0 +1,41 @@
+package com.learn.defaults;
+
+/**
+ * This Client implements Interface1, Interface2 and Interface3
+ *
+ * Order of resolving the method calls during runtime.
+ *  1 -> Class that implements the interface.
+ *  2 -> the sub interface that extends the interface.
+ *
+ */
+public class Client123  implements Interface1, Interface2, Interface3{
+
+    /**
+     * The class that overrides the default method takes precedence
+     * over any other implementation that we have in other interfaces.
+     */
+    public void methodA() {
+        System.out.println("Inside methodA() from Client123");
+    }
+
+    public static void main(String[] args) {
+        Client123 client123 = new Client123();
+
+        /**
+         * This concept is called multiple inheritance.
+         * We are inheriting multiple behaviors from each and every interfaces.
+         * This was never possible before Java8
+         */
+        client123.methodA();
+        client123.methodB();
+        client123.methodC();
+
+
+        /**
+         * Let's add some more complexity
+         * by extending Interface1 in Interface2
+         * by extending Interface2 in Interface3
+         */
+        client123.methodA(); // resolve to the child implementations.
+    }
+}
diff --git a/Modern-Java-Examples/src/com/learn/defaults/Interface1.java b/Modern-Java-Examples/src/com/learn/defaults/Interface1.java
@@ -0,0 +1,8 @@
+package com.learn.defaults;
+
+public interface Interface1 {
+
+    default void methodA() {
+        System.out.println("Inside methodA() from Interface1");
+    }
+}
diff --git a/Modern-Java-Examples/src/com/learn/defaults/Interface2.java b/Modern-Java-Examples/src/com/learn/defaults/Interface2.java
@@ -0,0 +1,13 @@
+package com.learn.defaults;
+
+public interface Interface2 extends Interface1{
+
+    default void methodB() {
+        System.out.println("Inside methodB() from Interface2");
+    }
+
+    @Override
+    default void methodA() {
+        System.out.println("Inside methodA() from Interface2");
+    }
+}
diff --git a/Modern-Java-Examples/src/com/learn/defaults/Interface3.java b/Modern-Java-Examples/src/com/learn/defaults/Interface3.java
@@ -0,0 +1,10 @@
+package com.learn.defaults;
+
+public interface Interface3 extends Interface2{
+
+    default void methodC() {
+        System.out.println("Inside methodC()");
+    }
+
+
+}
diff --git a/README.md b/README.md
@@ -67,6 +67,7 @@ This repository contains the basic &amp; advance level examples related to Java
     * [sort using Comparator](Modern-Java-Examples/src/com/learn/defaults/DefaultsMethodsExample2.java)
     * [Comparator: nullsFirst and nullsLast](Modern-Java-Examples/src/com/learn/defaults/DefaultsMethodsExample2.java)
     * [default and static methods in Interface](Modern-Java-Examples/src/com/learn/defaults/Multiplier.java)
+    * [default method Multiple Inheritance](Modern-Java-Examples/src/com/learn/defaults/Client123.java)
 
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