plugins/devkit/devkit-java-tests/testData/codeInsight/redundantComponentInterfaceClass.xml

<idea-plugin>
  <project-components>
    <component>
      <warning descr="Redundant tag 'interfaceClass'"><interface-class>java.lang.String</interface-class></warning>
      <implementation-class>java.lang.String</implementation-class>
    </component>

    <component>
      <interface-class>java.lang.Number</interface-class>
      <implementation-class>java.lang.Double</implementation-class>
      <headless-implementation-class>java.lang.String</headless-implementation-class>
    </component>

    <component>
      <warning descr="Redundant tag 'interfaceClass'"><interface-class>java.lang.String</interface-class></warning>
      <implementation-class>java.lang.String</implementation-class>
      <headless-implementation-class/>
    </component>

  </project-components>
</idea-plugin>