Code maturity

'Throwable' printed to 'System.out'  

Reports calls to System.out.println() with an exception as an argument.

Call to 'Thread.dumpStack()'  

Reports usages of Thread.dumpStack().

Call to 'printStackTrace()'  

Reports calls to Throwable.printStackTrace() without arguments.

Commented out code  

Reports comments that contain Java code.

Deprecated API usage  

Reports usages of deprecated classes, fields, and methods.

Deprecated member is still used  

Reports deprecated classes, methods, and fields that are used in your code nonetheless.

Method can be extracted  

Suggests extracting fragments of code to a separate method to make code more clear.

Null value for Optional type  

Reports null assigned to Optional variable or returned from method returning Optional.

Redundant @ScheduledForRemoval annotation  

Reports usages of @ApiStatus.ScheduledForRemoval annotation without inVersion attribute in code which targets Java 9 or newer version.

Usage of API marked for removal  

Reports usages of deprecated APIs (classes, fields, and methods) that are marked for removal with @Deprecated(forRemoval=true).

Use of 'System.out' or 'System.err'  

Reports usages of System.out or System.err.

Use of obsolete collection type  

Reports usages of java.util.Vector, java.util.Hashtable and java.util.Stack.

Use of obsolete date-time API  

Reports usages of java.util.Date, java.util.Calendar, java.util.GregorianCalendar, java.util.TimeZone, and java.util.SimpleTimeZone.