Added enum based singleton

Author: javamultiplex

enum-singleton.ser

@@ -0,0 +1,25 @@
+package com.javamultiplex.pattern.creational.singleton;
+
+/**
+ * @author Rohit Agarwal on 29/08/20 11:19 pm
+ * @copyright www.javamultiplex.com
+ */
+
+//enum is by default serializable
+public enum EnumBasedSingleton {
+    INSTANCE;
+
+    private int value;
+
+    EnumBasedSingleton() {
+        value = 42;
+    }
+
+    public int getValue() {
+        return value;
+    }
+
+    public void setValue(int value) {
+        this.value = value;
+    }
+}

src/main/java/com/javamultiplex/pattern/creational/singleton/EnumBasedSingleton.java

@@ -0,0 +1,23 @@
+package com.javamultiplex.pattern.creational.singleton;
+
+import com.javamultiplex.util.SerializationUtil;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+
+/**
+ * @author Rohit Agarwal on 29/08/20 11:21 pm
+ * @copyright www.javamultiplex.com
+ */
+public class EnumBasedSingletonClient {
+
+    @Test
+    public void shouldNotCreateTwoInstances() throws IOException, ClassNotFoundException {
+        EnumBasedSingleton enumBasedSingleton = EnumBasedSingleton.INSTANCE;
+        enumBasedSingleton.setValue(13);
+        System.out.println(enumBasedSingleton.name());
+        SerializationUtil.serialize(enumBasedSingleton,"enum-singleton.ser");
+        EnumBasedSingleton another = (EnumBasedSingleton)SerializationUtil.deserialize("enum-singleton.ser");
+        System.out.println(another.getValue());
+    }
+}