Fields

Fields provides field-hierarchy lookup and helpers for unwrapping reflection exceptions.

getSuperClassDeclaredFields(Class<?>) returns fields declared by the input class and its superclasses, including private fields but excluding fields declared by Object.

findField(Class<?>, String) searches the same hierarchy and returns the first matching Field, or null when no field exists. Finding a non-public field does not by itself make it accessible.

Field field = Fields.findField(MyClass.class, "name");
if (field != null && !field.isAccessible())
    field.setAccessible(true);

getUnderLayerErr(Throwable) unwraps nested InvocationTargetException and UndeclaredThrowableException instances. A wrapper without a cause is returned unchanged; a null input is rejected with IllegalArgumentException.

getUnderLayerErrMsg(Throwable) returns the unwrapped exception's detail message directly. It returns an empty string when the exception has no detail message, so an exception class name is never mistaken for message text.