This inspection helps to convert unmodifiable collections created before Java 9 to new collection factory methods like List.of or Set.of. Also since Java 10 the conversion to List.copyOf, etc. could be suggested.

Note that Java 9 collection factory methods do not accept null values. Also set elements and map keys are required to be different. It's not always possible to statically check whether original elements are different and not null. Using the checkbox you may enforce the inspection to warn only if original elements are compile-time constants, so the conversion is guaranteed to be correct.

This inspection is available since Java 9 only.

New in 2017.2