Basics of Java Programming - Part 2

 

What is Constructor in Java?

• A constructor is a member method
• Should have same name as class name
• It will never return anything
• It will use to allocate memory. 

class ConstructorExample {

int x;

String y;

public ConstructorExample() {

//constructor can be used to initialize default values for variables

x = 5;

y = "Hello World";

}

//parameterize Constructor

public ConstructorExample(int k, String str) {

//constructor can be used to initialize default values for variables

x = k;

y = str;

}

}

class inside a class(Inner Class)

class Outer {

int i;

class Inner {

public void show() {

System.out.println("Method inside inner class");

}

}

static class InnerStatic {

public void show() {

System.out.println("Method inside static inner class");

}

}

}

public class InnerDemo {

public static void main(String a[]) {

Outer outerObj = new Outer();

// access Inner class method

Outer.Inner innerObj= outerObj.new Inner();

innerObj.show();

Outer.InnerStatic innerStaticObj = new Outer.InnerStatic();

innerStaticObj.show();

}

}

// OUTPUT: 

// Method inside inner class

// Method inside static inner class