static

수업소개

static 키워드에 대해서 살펴보는 수업입니다. 

 

 

 

강의

소스코드

class Foo{
    public static String classVar = "I class var";
	public String instanceVar = "I instance var";
	public static void classMethod() {
		System.out.println(classVar); // Ok
//		System.out.println(instanceVar); // Error
	}
	public void instanceMethod() {
		System.out.println(classVar); // Ok
		System.out.println(instanceVar); // Ok
	}
}
public class StaticApp {

	public static void main(String[] args) {
		System.out.println(Foo.classVar); // OK
//		System.out.println(Foo.instanceVar); // Error
		Foo.classMethod();
//		Foo.instanceMethod();
		
		Foo f1 = new Foo();
		Foo f2 = new Foo();
//		
		System.out.println(f1.classVar); // I class var
		System.out.println(f1.instanceVar); // I instance var
//		
		f1.classVar = "changed by f1";
		System.out.println(Foo.classVar); // changed by f1
		System.out.println(f2.classVar);  // changed by f1
//		
		f1.instanceVar = "changed by f1";
		System.out.println(f1.instanceVar); // changed by f1
		System.out.println(f2.instanceVar); // I instance var
	}

}