[PATCH] Simplification proposal regarding TYPE-field initialization in primitive wrappers

[Johannes Kuhn]

On November 26, 2019 8:29:06 PM GMT+01:00, "Сергей Цыпанов" <sergei.tsypanov at yandex.ru> wrote:
>Hello,
>
>while using java.lang.Integer.TYPE I've found out that currently
>wrapper classes for primitives initialize their own TYPE-fields by
>calling native method java.lang.Class.getPrimitiveClass().
>
>This can be simplified by changing existing declaration (here for
>java.lang.Integer)
>
>@SuppressWarnings("unchecked")
>public static final Class<Integer>  TYPE = (Class<Integer>)
>Class.getPrimitiveClass("int");
>
>to
>
>public static final Class<Integer>  TYPE = int.class;
>
>This is likely to improve start-up time as Class.getPrimitiveClass() is
>called 9 times (8 primitive type wrappers + java.lang.Void), after the
>change this method is not called at all and thus can be removed along
>with its backing C++ code on VM-side. The fields are initialized purely
>on Java side.
>
>I've verified correctness of the substitution with this test run on JDK
>11
>
>@Test
>void name() {
>  assert void.class == Void.TYPE;
>  assert boolean.class == Boolean.TYPE;
>  assert byte.class == Byte.TYPE;
>  assert char.class == Character.TYPE;
>  assert short.class == Short.TYPE;
>  assert int.class == Integer.TYPE;
>  assert long.class == Long.TYPE;
>  assert float.class == Float.TYPE;
>  assert double.class == Double.TYPE;
>}
>
>The patch is attached.
>
>Regards,
>Sergey Tsypanov
Hi,
a few questions:
What does System.out.println(int.class); with your patch print? "int" or "null"?

I suspect that it will print null, because to my knowledge, int.class will be compiled to a getstatic Integer.TYPE, so your test basically tests if Integer.TYPE == Integer.TYPE.

Also, do the tier1 tests succeed with your patch?

With best regards,
Johannes