Need help

[captaincool]

Hi all,
i just now started learning java. i went through Head First Java. but i am not able to understand static and non-static members and methods. can anyone plz tel why should we use static or non-static in code.


Thanks

[subith86]

see the below code

public class RegexTest {

	int i = 0;
	//static int i = 0;

	public static void main(String[] args) {
		RegexTest obj1 = new RegexTest();
		RegexTest obj2 = new RegexTest();
		RegexTest obj3 = new RegexTest();
		obj1.myMethod();
		obj2.myMethod();
		obj3.myMethod();
	}

	private void myMethod() {
		
		System.out.println("i value while entering = "+i);
		i++;
		System.out.println("i value while leaving = "+i);
	}

}

I have declared an integer i.
I have commented one line, a static integer i.

First you execute this code and see the result. Then comment int i = 0 and uncomment static int i = 0 and see the result. Compare both. Then you'll understand why static variable :)

Meanwhile I'll post about static methods

[subith86]

Hope you got the concept of static variable.
Now static method is independent of instance. It is class specific.
To access a static method you should use the class name, the dot operator and the method name.

There are other restrictions also,
a static method cannot access non-static variable (instance variable) directly.
a static method cannot be over-ridden