Inner class may be 'static'

Reports inner classes that can be made static.

A static inner class does not keep an implicit reference to its enclosing instance. This prevents a common cause of memory leaks and uses less memory per instance of the class.

Example:

public class Outer {
  class Inner { // not static
    public void foo() {
      bar("x");
    }

    private void bar(String string) {}
  }
}

After the quick-fix is applied:

public class Outer {
  static class Inner {
    public void foo() {
      bar("x");
    }

    private void bar(String string) {}
  }
}

Inspection options

Option	Type	Default
Ignore if annotated by	StringList	[org.junit.jupiter.api.Nested]

Inspection Details
Available in:	IntelliJ IDEA 2023.3, Qodana for JVM 2023.3
Plugin:	Java, 233.SNAPSHOT

Last modified: 13 July 2023