Converting a subclass type to a superclass type is known as up-casting.Converting a superclass type to a subclass type is known as down-casting.

Typecasting is converting one data type to another.Up-casting − Converting a subclass type to a superclass type is known as up casting.Exampleclass Super {    void Sample() {       System.out.println("method of super class");    } } public class Sub extends Super {    void Sample() {       System.out.println("method of sub class");    }        public static void main(String args[]) {       Super obj =(Super) new Sub(); obj.Sample();    } }Down-casting − Converting a superclass type to a subclass type is known as downcasting.Exampleclass Super {    void Sample() {     ... Read More

Multiple inheritances lead to ambiguity.For example, if there is a class named Sub and there are two classes Super1 and Super2 and if both contains a method named sample(). And if the class sub inherits both classes Super1 and Super2 then there will be two copies of the sampling method one from each superclass and it is ambiguous to decide which method to be executed.

Association of method call with the method body is known as binding in Java. There are two kinds of binding. Static binding In static binding the method call is bonded with the method body at compile time. This is also known as early binding. This is done using static, private and, final methods. Example class Super{ public static void sample(){ System.out.println("This is the method of super class"); } } Public class Sub extends Super{ Public static void sample(){ ... Read More

You can create an object of the class named Class in two ways −Using new keyword as −Class obj = new Class();Using the forName() method of the class named Class.Class obj = Class.forName("DemoTest");

You can access the private methods of a class using java reflection package.Step1 − Instantiate the Method class of the java.lang.reflect package by passing the method name of the method which is declared private.Step2 − Set the method accessible by passing value true to the setAccessible() method.Step3 − Finally, invoke the method using the invoke() method.Exampleimport java.lang.reflect.Method; public class DemoTest {    private void sampleMethod() {       System.out.println("hello");    } } public class SampleTest {    public static void main(String args[]) throws Exception {       Class c = Class.forName("DemoTest");       Object obj = c.newInstance(); ... Read More

An abstract method is the one which has no definition and declared abstract. In short, an abstract method contains only method signature without body. To use this method, you need to inherit this method by extending the class and provide the method definition. Example public abstract class Employee{ private String name; private String address; private int number; public abstract double computePay(); }

A native method is the one whose method implementation is done in other languages like c++ and Java. These programs are linked to Java using JNI or JNA interfaces. The difference between normal method and native method is That the native method declaration contains native keyword and, the implementation of the method will be other programming language. Example Tester.java public class Tester { public native int getValue(int i); public static void main(String[] args) { System.loadLibrary("Tester"); System.out.println(new Tester().getValue(2)); ... Read More

A native method in Java is a method whose implementation is written in other languages such as c and c++. The ‘native’ keyword is used before a method to indicate that it is implemented in other language.

Whenever, you want to pass different number of arguments each time you call a method you should use vararg methods. This example creates sumvarargs() method which takes variable no of int numbers as an argument and returns the sum of these arguments as an output. Example Live Demo public class Main { static int sumvarargs(int... intArrays) { int sum, i; sum = 0; for(i = 0; i< intArrays.length; i++) { ... Read More