fix: add xlint and file.encoding to Java (#2471)

Co-authored-by: weather-tracker <[email protected]>
Co-authored-by: Amin Yahyaabadi <[email protected]>

* Adding back '-J-Dfile.encoding=UTF-8' for javac so its warning messages are printed in UTF-8
as well as its source files are treated as UTF-8 encoding.
* Adding back -Xlint for reporting detailed warning messages for compilers
* removing quotation marks around file.encoding and UTF-8 for java command, 
since java command does not understand quotation marks when it is not removed by the shell 
(cmd.exe won't interpret that)

update for issue #1166

Author: mhatano

lib/grammars/java.js

@@ -8,7 +8,7 @@ function JavaArgs(filepath, context) {
   const className = GrammarUtils.Java.getClassName(context)
   const classPackages = GrammarUtils.Java.getClassPackage(context)
   const tempFolder = GrammarUtils.createTempFolder("jar-")
-  const cmd = `javac -encoding UTF-8 -sourcepath '${sourcePath}' -d '${tempFolder}' '${filepath}' && java -D'file.encoding'='UTF-8' -cp '${tempFolder}' ${classPackages}${className}`
+  const cmd = `javac -encoding UTF-8 -J-Dfile.encoding=UTF-8 -Xlint -sourcepath '${sourcePath}' -d '${tempFolder}' '${filepath}' && java -Dfile.encoding=UTF-8 -cp '${tempFolder}' ${classPackages}${className}`
   return GrammarUtils.formatArgs(cmd)
 }