default method in interfaces

spdpiyush · spdpiyush · commit b546e2a8fa4a · 2025-03-13T10:49:23.000+05:30
diff --git a/Modern-Java-Examples/src/com/learn/defaults/DefaultsMethodExample.java b/Modern-Java-Examples/src/com/learn/defaults/DefaultsMethodExample.java
@@ -0,0 +1,37 @@
+package com.learn.defaults;
+
+import com.learn.data.Student;
+import com.learn.data.StudentDataBase;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class DefaultsMethodExample {
+
+    public static void main(String[] args) {
+
+        /**
+         * Sort the list of names in alphabetical order.
+         */
+        List<String> stringList = StudentDataBase.getAllStudents().stream().map(Student::getName).collect(Collectors.toList());
+
+        /**
+         * Prior Java8, by using Collections class.
+         */
+        Collections.sort(stringList); // sort the input in alphabetical order
+        System.out.println("Sorted list using Collections.sort() : " + stringList);
+
+        /**
+         * Java8 approach,
+         * In Java8, the List interface has a default method sort
+         * And this sort method, takes an input called Comparator.
+         * By this default methods, it helps to add new functionalities into the interfaces so that this interface
+         * can evolve according to the new technology and new use cases.
+         */
+        List<String> stringList1 = StudentDataBase.getAllStudents().stream().map(Student::getName).collect(Collectors.toList());
+        stringList1.sort(Comparator.naturalOrder());
+        System.out.println("Sorted list using List.sort() : " + stringList1);
+    }
+}
diff --git a/README.md b/README.md
@@ -62,6 +62,8 @@ This repository contains the basic &amp; advance level examples related to Java
     * [orElse(), orElseGet() and orElseThrow()](Modern-Java-Examples/src/com/learn/optional/OptionalOrElseExample.java)
     * [ifPresent() and isPresent()](Modern-Java-Examples/src/com/learn/optional/OptionalPresentExample.java)
     * [filter(), map() and flatMap()](Modern-Java-Examples/src/com/learn/optional/OptionalMapFlatMapExample.java)
+  * **Defaults**
+    * [default methods](Modern-Java-Examples/src/com/learn/defaults/DefaultsMethodExample.java)
 
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