[NetBeans 4.1, JDK 1.5.0_03]

Put following code into some java class:

    class InnerClass implements InnerInterface {
        private String field;
        public int method() {
            return 0;
        }
    }
    
    interface InnerInterface {
        public int method();
        public String anotherMethod();
    }

Invoking Tools | Synchronize on the InnerClass class node in Explorer has no
efect on the class.