Static block/variables/methods are very powerful in java.

When we say static it is static throughout the application. If you declare a static variable in a stand-alone application, the life of the variable will be throughout the end of the application but in the case of the web application, static variable  has life till the web server is stopped.

Static variables are executed at first the program runs. Next the static block is executed. Static methods are executed when a call is raised.

Note: Static methods can call only static methods. To call non-static methods instance of the class should be created

Refer below code for better understanding

class UseStatic

{

static int a=3;

static int b;

static void meth(int x)

{

System.out.println(”x: “+x);

System.out.println(”a: “+a);

System.out.println(”b: “+b);

}

static

{

System.out.println(”static block initialized: “);

b=a*4;

}

public static void main(String [] args)

{

meth(42);

}

}