code: public static @CheckForNull
      JavaClassAndMethod findMethod(JavaClass javaClass, String methodName, String methodSig) {
          return findMethod(javaClass, methodName, methodSig, ANY_METHOD);
      }
docs: Find a method in given class.
  
  @param javaClass
  the class
  @param methodName
  the name of the method
  @param methodSig
  the signature of the method
  @return the JavaClassAndMethod, or null if no such method exists in the
  class