RFR: 8274811: Remove superfluous use of boxing in java.base

[Сергей Цыпанов]

On Sat, 11 Sep 2021 12:11:50 GMT, Andrey Turbanov <github.com+741251+turbanoff at openjdk.org> wrote:

> Usages of primitive types should be preferred and makes code easier to read.
> Similar cleanups:
> 1. [JDK-8273168](https://bugs.openjdk.java.net/browse/JDK-8273168) java.desktop
> 2. [JDK-8274234](https://bugs.openjdk.java.net/browse/JDK-8274234) java.sql.rowset

src/java.base/share/classes/java/util/ResourceBundle.java line 3732:

> 3730:     }
> 3731: 
> 3732:     private static final boolean TRACE_ON = Boolean.parseBoolean(

I think for `Boolean` it doesn't make significant difference, as both `Boolean.TRUE` and `Boolean.FALSE` are cached and initialized immediately along with the class itself:

public static Boolean valueOf(String s) {
  return parseBoolean(s) ? TRUE : FALSE;
}

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PR: https://git.openjdk.java.net/jdk/pull/5481