ThispaperdescribesJSpy,asystemforhigh-levelinstrumentationofJavabytecodeanditsusewithJPaX,oursystemforruntimeanalysisofJavaprograms.JPaXmonitorstheexecutionoftemporallogicformulasandperformspredicativeanalysisofdeadlocksanddataraces.JSpy’sinputisaninstrumentationspecification,whichcons