Static Methods and Variables in Java

Static methods and variables are shared by all instances of the class. Static variables are initialized when a class is loaded whereas instance variables are initialized when an instance of the class is created. Static methods belong to a class, therefore, it can only access static members of the class and it can be called before instantiating the class.

class StaticCase {
	static int staticCounter = 0;
	int nonStaticCounter = 0;
	
	StaticCase() {
		staticCounter++; //class level
		nonStaticCounter++; //instance level
	}
}
	
class StaticCaseImpl {
	
        //static method, entry point
	public static void main(String... args) {
                //StaticCase.nonStaticCounter, error, not a static variable
	
		StaticCase sc1 = new StaticCase();
		StaticCase sc2 = new StaticCase();
	
		System.out.println("staticCounter sc1: " + sc1.staticCounter);
		//output is staticCounter sc1: 2
                //or in static context, StaticCase.staticCounter
		System.out.println("nonStaticCounter sc1: " + sc1.nonStaticCounter);
		//output is nonStaticCounter sc1: 1
	
		System.out.println("staticCounter sc2: " + sc2.staticCounter);
		//output is staticCounter sc2: 2
                //or in static context, StaticCase.staticCounter
		system.out.println("nonStaticCounter sc2: " + sc2.nonStaticCounter);
		//output is nonStaticCounter sc2: 1
	}
}