Using 'instanceof' with patterns

Reports instanceof with patterns and suggests converting them to ordinary instanceof with casts.

This inspection makes it possible to move instanceof with patterns to a codebase using an earlier Java version by applying the quick-fix.

Note that the result can be not completely equivalent to the original instanceof with patterns when a complex expression before instanceof is used. In this case this expression will be reevaluated.

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.

PatternVariablesCanBeReplacedWithCast

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 | Code style issues

Example:

  if (object instanceof String txt && txt.length() == 1) {
      System.out.println(txt);
  } else {
      return;
  }
  System.out.println(txt);

After the quick-fix is applied:

  if (object instanceof String && ((String) object).length() ==1) {
      String txt = (String) object;
      System.out.println(txt);
  } else {
      return;
  }
  String txt = (String) object;
  System.out.println(txt);

Inspection options

Here you can find the description of settings available for the Using 'instanceof' with patterns inspection, and the reference of their default values.

Try to preserve unused variables from patterns during quickfix: Default: Selected

Inspection Details
By default bundled with:	IntelliJ IDEA 2024.2, Qodana for JVM 2024.2,
Can be installed with plugin:	Java, 242.22892

Last modified: 11 September 2024