Redundant interface declaration

Reports interfaces in a class' implements list or an interface's extends list that are already implemented by a superclass or extended by a superinterface. Such declarations are unnecessary and may be safely removed.

Example:

  class X implements One, Two {
  }
  interface One {}
  interface Two extends One {}

After the quick-fix is applied:

  class X implements Two {
  }
  interface One {}
  interface Two extends One {}

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.

RedundantInterfaceDeclaration

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 | Inheritance issues

Use the options to not report on Serializable or Externalizable in an extends or implements list.

Inspection options

Here you can find the description of settings available for the Redundant interface declaration inspection, and the reference of their default values.

Ignore 'java.io.Serializable': Not selected
Ignore 'java.lang.Cloneable': Not 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