errorprone cleanliness

go through the code by instating error prone and fix any issues it reports. Once that epic work is done we can permanently install errorprone as a pre-commit hook.

```
commit 9f9a2b6b7e094537fea75f633d355f983d4c15d7
Author: Daan Hoogland
Date: Thu Jan 12 19:32:35 2023 +0100

errorprone

diff --git a/pom.xml b/pom.xml
index 204c74cc76..13c46d7521 100644
--- a/pom.xml
+++ b/pom.xml
@@ -817,6 +817,32 @@



+
+ org.apache.maven.plugins
+ maven-compiler-plugin
+ ${cs.compiler-plugin.version}
+
+ 8
+ 8
+ UTF-8
+
+ -XDcompilePolicy=simple
+ -Xplugin:ErrorProne
+
+
+
+ com.google.errorprone
+ error_prone_core
+ 2.18.0
+
+
+
+
+



@@ -1074,15 +1100,26 @@

${cs.jdk.version}
${cs.jdk.version}
- true
- 128m
- 512m
+ UTF-8

-XDignore.symbol.file=true
--add-opens=java.base/java.lang=ALL-UNNAMED
--add-exports=java.base/sun.security.x509=ALL-UNNAMED
--add-exports=java.base/sun.security.provider=ALL-UNNAMED
+ -XDcompilePolicy=simple
+ -Xplugin:ErrorProne
+ --illegal-access=warn

+
+
+ com.google.errorprone
+ error_prone_core
+ 2.18.0
+
+
+ true
+ 128m
+ 512m



```

the above can be added to the main pom.xml and for any issues reported child issues of this or PR can be created directly. The scope of this is would be enormous and too big to deal with at once.

Start with the Error Prone compiler configuration shown in pom.xml and review linked PR #12425 before beginning. Run the Maven build to identify reported issues, then track individual fixes as child issues or pull requests; the work is done when the reported issues are resolved and Error Prone can remain as a pre-commit hook.

Written by the indexing model from the issue text.