Question

Is there a difference between the following two :

ArrayList list = getData();

public ArrayList getData(){
    return otherList;
}

and

ArrayList list = someOtherArrayList;

Answer 1

ArrayList list = someOtherArrayList;

In this case directly address of someOtherArrayList is assigned to list.

ArrayList list = getData();

public ArrayList getData() {   
    return otherList;
}

In this case, address of list returned is copied into temporary variable and later temporary variable to list. Here address copied in temporary variable because : When function returns, all its data on stack is deallocated/deleted, so otherList object reference is also deleted. But before that it is reference/address is copied into temporary variable. When address from temporary variable is copied in list variable. It is also deleted.