Compiler issues

Javac quirks  

Reports known Javac issues, performance problems, and incompatibilities.

Preview Feature warning  

Reports usages of Preview Feature APIs, i.e.

Unchecked warning  

Reports code on which an unchecked warning will be issued by the javac compiler.

Value-based warnings  

Reports attempts to synchronize on an instance of a value-based class that produce compile-time warnings and raise run-time exceptions starting from Java 16.