JAVA中以下2个代码块之间有什么区别

Question

Whats the difference between using

Object example1 = 3;
System.out.println(example1);

and

int example2 = 3;
System.out.println(example2);

Both print 3 , so what is the difference between using int and Object ?

Answer 1

The first block wraps the literal value 3 in an Integer object. While the second one assigns the literal value 3 to an int variable.

Both blocks should output 3 , there is nothing weird about that.

Answer 2

3 is an int , one of the native types in Java.

If you assign it to Object it is auto-boxed into an Integer which is a regular class.

Therefore the difference is that in the first case you have in instance of the Integer class stored in a variable of type Object . In the second case you have a primitive int variable.