'Set' can be replaced with 'EnumSet'

Reports instantiations of java.util.Set objects whose content types are enumerated classes. Such Set objects can be replaced with java.util.EnumSet objects.

EnumSet implementations can be much more efficient compared to other sets, as the underlying data structure is a bit vector. Use the quick-fix to replace the initializer with a call to EnumSet.noneOf(). This quick-fix is not available when the type of the variable is a sub-class of Set.

Example:

  enum MyEnum { FOO, BAR; }

  Set<MyEnum> enums = new HashSet<MyEnum>();

After the quick-fix is applied:

  enum MyEnum { FOO, BAR; }

  Set<MyEnum> enums = EnumSet.noneOf(MyEnum.class);

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

SetReplaceableByEnumSet

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Java | Performance

Suppressing Inspection

You can suppress this inspection by placing the following comment marker before the code fragment where you no longer want messages from this inspection to appear:

//noinspection SetReplaceableByEnumSet

More detailed instructions as well as other ways and options that you have can be found in the product documentation:

IntelliJ IDEA 2025.2

Inspection Details
By default bundled with:	IntelliJ IDEA 2025.2, Qodana for JVM 2025.2,

Last modified: 18 September 2025