spring - javassist does not catch exception -

spring - javassist does not catch exception -

i have main app(spring) , java-agent app(scala), seek methods(from maim app) name 'doget' , replace body next

val replace = """ |{system.out.println("before"); | $_ = $proceed($$); | system.out.println($1); | system.out.println($2); | charresponsewrapper responsewrapper = new charresponsewrapper((httpservletresponse) $2); | system.out.println(responsewrapper.tostring();); | system.out.println("after");}""".stripmargin

but line charresponsewrapper creating cause problems , want know problem on line. add together catching method, seemed here

method.addcatch(" system.out.println(\"[error]\"); ", pool.get("java.lang.exception"));

but when calling these methods prints not print. expecting minimum printing '[error]'.

what cause of exception not catched?

spring scala javassist