The aspect-oriented paradigm allows weaving aspects in different join points of a program. Aspects can modify object fields and method control flow, thus possibly introducing subtle and undesired interactions (conflicts) among aspects and objects, which are not easily detectable. In this paper we propose a fully automated approach to discover conflicts among classes and aspects directly from Java bytecode. The novelty of this work is the usage of a rule engine for identifying possible conflicts among advices, methods, and fields. The knowledge base is obtained through static analysis of classes and aspects bytecode. The possible conflicts are represented by means of rules that can be easily extended and customized.