Question

Is there a difference between the following variable declarations?

Class A {
  private int a;
  A(){
    a= 2;
  }
}

VS

Class A {
  private int a  = 2;
  A(){
  } 
}

Will garbage collection work any differently?

Answer 1

There is no difference in the behaviour of your two initialisations. In the first example the a = 2 will happen just before the constructor code is called. If you made a final:

private final int a; //first example

private final int a = 2; //second example

Then you would see a difference between what you could do in the constructor:

 A(){ //The blank final field a may not have been initialized for first example
 }

 A(){
   a = 2; //The final field Apple.a cannot be assigned for second example
 }