Getting the object of a class that is already running

Question

there is one class a
i created an object of class a
a a1 = new a();
i am in class B
i want to get the 'a' class instance that is already running ie i want to access object a1 and these classes are not related. Can i get them?
If yes how?
It is urgent.

Answer 1

1. class B could encapsulate class A.
Class B
   A a1;
   public B(A a1)
      this.a1 = a1;
   //......remaining part of class
}Now when you create an object of B, you could pass the a's object to B's constructor,
   A a1 = new A();
   B b1 = new B(a1);
  // to access the a object within b, usage is as below
   b1.a1.<a's methods>2. If you wish that the object of class A is required only in some methods of B, pass it as a parameter to B's methods
class B
   public void someMethodThatNeedsA'sObject(A a1)
      //do something with a's object here
      //do something with B's own variables
   psvm() //main
       A a1 = new A();
       B b1 = new B();
       b1.someMethodThatNeedsA'sObject(a1);
}ram.