Eclipse warning about synthetic accessor for private static nested classes in Java?

Question

My coworker suggested making several of the Eclipse code-formatting and warning settings to be more rigorous. The majority of these changes make sense, but I get this one we

Answer 1

To help folks out, here is what you get if you use the original class code in the question with

javac -XD-printflat WeirdInnerClassJavaWarning.java -d tmp

Raw output, compiler added the comments. Note the addition of the synthetic package private class and constructor.

public class WeirdInnerClassJavaWarning {
    {
    }

    public WeirdInnerClassJavaWarning() {
        super();
    }
    {
    }
    private final WeirdInnerClassJavaWarning$InnerClass anInstance;
    {
        this.anInstance = new WeirdInnerClassJavaWarning$InnerClass(null);
        this.anInstance.doSomething();
    }
}

class WeirdInnerClassJavaWarning$InnerClass {

    /*synthetic*/ WeirdInnerClassJavaWarning$InnerClass(WeirdInnerClassJavaWarning$1 x0) {
        this();
    }

    private WeirdInnerClassJavaWarning$InnerClass() {
        super();
    }

    public void doSomething() {
    }
}

/*synthetic*/ class WeirdInnerClassJavaWarning$1 {
}