RFR: 8272805: Avoid looking up standard charsets

Sergey Bylokhov serb at openjdk.java.net
Sun Aug 22 06:28:18 UTC 2021

This is the continuation of JDK-8233884, JDK-8271456, and JDK-8272120.
See https://github.com/openjdk/jdk/pull/5063 and https://github.com/openjdk/jdk/pull/4951

In many places standard charsets are looked up via their names, for example:

This could be done more efficiently(up to x20 time faster) with use of java.nio.charset.StandardCharsets:

The later variant also makes the code cleaner, as it is known not to throw UnsupportedEncodingException in contrary to the former variant.

This change includes:
 * demo/utils
 * jdk.xx packages
 * Some places were missed in the previous changes. I have found it by tracing the calls to the Charset.forName() by executing tier1,2,3 and desktop tests. Also checked for "aliases" usage.

Some performance discussion: https://github.com/openjdk/jdk/pull/5063

Code excluded in this fix: the Xerces library(should be fixed upstream), J2DBench(should be compatible to 1.4), some code in the "java.naming"(the change there is not straightforward, will do it later).

Tested by the tier1/tier2/tier3 tests on Linux/Windows/macOS.


Commit messages:
 - Fix related imports
 - Merge branch 'master' into standard-encodings-in-non-public-modules
 - Cleanup UnsupportedEncodingException
 - Update PacketStream.java
 - Rollback TextTests, should be compatible with jdk1.4
 - Rollback TextRenderTests, should be compatible with jdk1.4
 - Cleanup the UnsupportedEncodingException
 - aliases for ISO_8859_1
 - Update imageio
 - Initial fix

Changes: https://git.openjdk.java.net/jdk/pull/5210/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5210&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8272805
  Stats: 333 lines in 48 files changed: 91 ins; 123 del; 119 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5210.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5210/head:pull/5210

PR: https://git.openjdk.java.net/jdk/pull/5210

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