Static is a pain in the ass word!

[Addez]

Hi, I just cant manage to figur out what static stands for, all I know is that it's the shittiest word in java.
It keeps causeing so freakn unbelivable many error that Im about to shit my pants! :mad:

Can someone explain in clean english why this doesnt work:

 
class ExtendingTesting {
    private static int valve = 0; 
    
    void changeValue(int c){
    	this.valve = c;
    }
    void showValue(){
    	System.out.println("Value: "+this.valve);
    }
    
    
}


class hi extends ExtendingTesting {
	
	public static void asa (){
		int a = 10;
		hi.changeValue(a);
		hi.showValue();
	}
}

cause I keep getting the error:

non-static method changeValue(int) cannot be referenced from a static context

It's a true pain in the ass, can someone help me?

[emceenugget]

hi.changeValue() isn't static, but you're calling it like it is.

[TenF]

Correct me if I'm wrong...

I was taught that static means the method/class/whatever does not work with/on an object of any sort.

However, I've never quite understood when a method can be declared static and when not.

I do know that it should work if you get rid of the 'static' in your program. A method can be static without you telling it it is, right? ;)

[quad64bit]

Static means that something that is static does not require object instantiation to be used. You make a method or variable static when you want to use it outside of the class without making a new instance of that class. For example:

class Numbers{
    static double pi = 3.141592653589793D;
}

class Test{
    public void print(){
        System.out.println(Numbers.pi);
    }
}

This works because the pi field is static. If pi was NOT static, you would have to have done it this way:

class Numbers{
   double pi = 3.141592653589793D;
}

class Test{
    public void print(){
        Numbers num = new Numbers();
        System.out.println(num.pi);
    }
}

This is true for methods as well. Static is a wonderful tool when you know what it does and how to use it -- also, it is used almost everywhere in the java class library.

The only thing you should make static as a new java programmer is a main method:

public static void main(String[] args){
    //do something
}

Main methods must be static, but avoid it elsewhere until you have a real need for it and a deeper understanding of it.

[quad64bit]

Also, please read my post to a similar question on another thread. I explained static there too and gave some other examples:
Static and non staic reference, Synchronized and unsynchronized, abstarct class,