How can i use same object in different classes in Java

Question

Suppose i have 3 java classes A , B and C

I need to create an object of class C that is used in both A and B but the problem in creating the object separately is that the constructor of class c is called 2 times. But i want the constructor to be called just once.

So i want to use the object created in class A into class b.

Answer 1

So create the object once, and pass it into the constructors of A and B:

C c = new C();
A a = new A(c);
B b = new B(c);

...

public class A 
{
    private final C c;

    public A(C c)
    {
        this.c = c;
    }
}

Note that this is very common in Java as a form of dependency injection such that objects are told about their collaborators rather than constructing them themselves.

Answer 2

Create object C outside of both A and B and have the constructors of A and B accept an instance of class C.

class A {
   public A( C c ) {
       ....
   }
}

class B {
   public B( C c ) {
       ....
   }
}