I am new to Java.
I want to ask about object initialization. First, I make a class.
public class A {
....
}
Then at the main class, the A class is instantiated.
A a = new A();
Now, the question is, whether these two codes are the same?
A aa = a;
and
A aa = new A();
A aa = a
will make a reference to object a, however
A aa = new A();
will make a new object of type A.
No they are totally different!
A aa = a;
Then aa and a refert to the same object in memory.
A aa = new A();
Then aa is a new object. And you have now two objects on the stack.
A a = new A();
A aa = a;
aa refers to the same object a.
A aa = new A();
about statement created new object of type A which is different from the a.
No, they are different.
While A aa = new A(); creates a new Object of type A,
A aa = a; just passes the reference of a to aa, which means, those two point to the same Object.
You can verify this by printing the hashcode of a and aa.
In the first case A aa = a; calling hashCode() on both aa and a will yield the same result, since both point to the same Object.
In your second case A aa = new A(); calling hashCode() will yield different results, since you're creating a whole new instance of A.
