Testing a servlet static method not allowed?

Question

When I try from within JUnit I enter:

public InvocationTargetException(Throwable target) {
    super((Throwable)null);  // Disallow initCause
    this.target = target;
}

I know that I could put that code in an outer class and have servlet call it.

Can I not test a static method of a servlet in Java EE 5 container, from a JUnit test method by simply calling ServletX.doX()? If so, why could I be getting this error on attempt? Any special JUnit configurations?