Explicit static initialization with the static clause : Initialization Block « Class Definition « Java Tutorial

1. Java Tutorial
2. Class Definition
3. Initialization Block

class MyClass {
  MyClass(int marker) {
    System.out.println("Cup(" + marker + ")");
  }

  void f(int marker) {
    System.out.println("f(" + marker + ")");
  }
}

class MyStatic {
  static MyClass c1;

  static MyClass c2;
  static {
    c1 = new MyClass(1);
    c2 = new MyClass(2);
  }

  MyStatic() {
    System.out.println("Cups()");
  }
}

public class MainClass {
  public static void main(String[] args) {
    System.out.println("Inside main()");
    MyStatic.c1.f(99); // (1)
  }
}

Inside main()
Cup(1)
Cup(2)
f(99)