Provide an action from the context menu of interfaces (e.g. New->Wrapper) and a file template (in the New File dialog) to create a Wrapper class from an interface.

e.g.

public interface MyInterface{
  void setBor(Bar bar);
  Bar getBar();
  void foo();
}

should create:

public class MyInterfaceWrapper{
  private final MyInterface myInterface;

  public MyInterfaceWrapper(MyInterface myInterface){
    this.myInterface = myInterface;
  }

  @Override
  public void setBoo(Bar bar){
    myInterface.setBar(bar);
  }
  
  @Override
  public Bar getBar(){
    return myInterface.getBar();
  }

  @Override
  public void foo(){
    myInterface.foo();
  }

}