MethodHiding

rahulXbarnwal · rahulXbarnwal · commit 7ea4d151a284 · 2026-01-18T13:27:25.000+05:30
diff --git a/src/oops2/MethodHiding.java b/src/oops2/MethodHiding.java
@@ -0,0 +1,54 @@
+package oops2;
+
+// static variables and methods get inherited,
+// but they do not behave like normal overridden methods
+
+// static variables is accessible in child
+
+class Parent {
+    static int x = 20;
+
+    static void staticMethod() {
+        System.out.println("Parent static");
+    }
+
+    void instanceMethod() {
+        System.out.println("Parent instance");
+    }
+}
+
+// static methods are accessible in child
+class Child extends Parent {
+
+}
+
+// static methods can't be overridden
+// since overriding is run time polymorphism
+// static methods belongs to class , not object
+// static binding happens at compile time
+class Child2 extends Parent {
+    static void staticMethod() {
+        System.out.println("Child2 static");
+    }
+
+    @Override
+    void instanceMethod() {
+        System.out.println("Child2 instance");
+    }
+}
+
+public class MethodHiding {
+    public static void main(String[] args) {
+        System.out.println(Child.x); // 20
+        Child.staticMethod(); // Parent static
+
+        Parent p = new Child2();
+        p.staticMethod(); // Parent static
+        p.instanceMethod(); // Child2 instance
+
+        // because static methods are resolved using ref type, not object type
+        // Ref type = parent
+        // so Parent.show()
+        // this is method hiding
+    }
+}
diff --git a/src/oops2/Singleton.java b/src/oops2/Singleton.java
diff --git a/src/oops2/SingletonUsage.java b/src/oops2/SingletonUsage.java
@@ -0,0 +1,26 @@
+package oops2;
+
+class Singleton {
+    private static Singleton instance;
+
+    private Singleton() {
+        System.out.println("Singleton object created");
+    }
+
+    public static Singleton getInstance () {
+        if(instance == null) {
+            instance = new Singleton();
+        }
+        return instance;
+    }
+}
+
+public class SingletonUsage {
+    public static void main(String[] args) {
+
+        Singleton s1 = Singleton.getInstance();
+        Singleton s2 = Singleton.getInstance();
+
+        System.out.println(s1 == s2);
+    }
+}
