Tree map fixes

[Ihromant]

Added lots of various fixes for TreeMap. Explanation. I get https://github.com/pulseenergy/harmony-treemap/blob/master/src/test/java/org/apache/harmony/java/util/TreeMapTest.java this file (Apache 2.0 licensed), renamed it to TreeMapTest1, adapted to our testcases and noticed multiple failures. Then I fixed them one by one. So, now 2 options are possible:

1. Have two test files for TreeMap, one normal and one "verbose".
2. Remove this TreeMapTest1 file. Personally I don't want to extract exact cases that are failing or merge this tests because this is stupid work IMHO.

[konsoletyper]

I don't like the idea of committing this TreeMapTest1, but if you don't want to merge it with TreeMapTest, at least please resolve checkstyle issues.

[Ihromant]

Could you please fix checkstyle in gradle? When I'm running ./gradlew check it fails with:

FAILURE: Build failed with an exception.

* What went wrong:
Could not load the value of field `aliasSet` of `sun.nio.cs.UTF_8` bean found in field `charset` of `org.gradle.api.internal.resources.FileCollectionBackedTextResource` bean found in field `config` of task `:classlib:checkstyleMain` of type `org.gradle.api.plugins.quality.Checkstyle`.
> java.lang.reflect.InvocationTargetException (no error message)

[konsoletyper]

What Java version are you using? Is it 21? Gradle does not support Java 21 yet, so you should run from 17

[Ihromant]

Yes, it's 21.

[Ihromant]

Still, it worked earlier on 21. But ok, will downgrade for tests.

[konsoletyper]

I did not change anything significant here. The error is in Gradle, and it clearly states, that Java 21 is unsupported. Gradle doc also says that there's no support for running Gradle on Java 21 yet. I don't know what has changed, perhaps some random caching issues.

[Ihromant]

Now when I'm compiling with 17 Java it fails with

> Task :tests:compileTestJava FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':tests:compileTestJava'.
> error: invalid source release: 21

[konsoletyper]

Please, read this article: https://docs.gradle.org/current/userguide/toolchains.html

Personally, I run Gradle from IDEA and specify JDK 17 as Gradle run JDK, but project has both 17 and 21 installed, so Gradle toolchains work properly. If it's not an option, I don't have a quick answer.

You can also try keep running on 21, but play with these lines in gradle.properties:

org.gradle.caching=true
org.gradle.unsafe.configuration-cache=true

especially, with the second one

[Ihromant]

Thanks, setting this properties helped. Now checkstyle and build are successful.