Why do people still use primitive types in Java?

Question

Since Java 5, we\'ve had boxing/unboxing of primitive types so that int is wrapped to be java.lang.Integer, and so and and so forth.

I see

Answer 1

Can you really imagine a

  for (int i=0; i<10000; i++) {
      do something
  }

loop with java.lang.Integer instead? A java.lang.Integer is immutable, so each increment round the loop would create a new java object on the heap, rather than just increment the int on the stack with a single JVM instruction. The performance would be diabolical.

I would really disagree that it's much mode convenient to use java.lang.Integer than int. On the contrary. Autoboxing means that you can use int where you would otherwise be forced to use Integer, and the java compiler takes care of inserting the code to create the new Integer object for you. Autoboxing is all about allowing you to use an int where an Integer is expected, with the compiler inserting the relevant object construction. It in no way removes or reduces the need for the int in the first place. With autoboxing you get the best of both worlds. You get an Integer created for you automatically when you need a heap based java object, and you get the speed and efficiency of an int when you are just doing arithmetic and local calculations.