public IsNullValueDataflow getIsNullValueDataflow(Method method) throws DataflowAnalysisException {
public IsNullValueDataflow getIsNullValueDataflow(Method method) throws DataflowAnalysisException, CFGBuilderException {
	public IsNullValueDataflow getIsNullValueDataflow(Method method) throws DataflowAnalysisException {		IsNullValueDataflow invDataflow = invDataflowMap.get(method);		if (invDataflow == null) {			MethodGen methodGen = getMethodGen(method);			CFG cfg = getCFG(method);			ValueNumberDataflow vnaDataflow = getValueNumberDataflow(method);			IsNullValueAnalysis invAnalysis = new IsNullValueAnalysis(methodGen, cfg, vnaDataflow);			invDataflow = new IsNullValueDataflow(cfg, invAnalysis);			invDataflow.execute();			invDataflowMap.put(method, invDataflow);		}		return invDataflow;	}