class A {
  int a;
  int b;

  public A() {
    a = 1;
    b = 2;
  }

  public int getA() {return a;}
  public int getB() {return b;}
}

class Factory {
private A a;
public A getA() {
    if (a == null) {
        synchronized(this) {
            if (a == null) {
                a = new A();
            }
        }
    }
    return a;
}