javassist 报错 ; is missing

String code = "for (String aa : tt){....}";

Exception in thread "main" javassist.CannotCompileException: [source error] ; is missing
    at javassist.CtNewMethod.make(CtNewMethod.java:84)
    at javassist.CtNewMethod.make(CtNewMethod.java:50)
    at javassist.CtMethod.make(CtMethod.java:140)
    at com.summersec.attack.deser.echo.AllEcho.genPayload(AllEcho.java:25)
    at com.summersec.attack.deser.util.Gadgets.createTemplatesImpl(Gadgets.java:65)
    at com.summersec.attack.deser.util.Gadgets.createTemplatesImpl(Gadgets.java:57)
    at com.summersec.attack.deser.echo.AllEcho.main(AllEcho.java:36)
Caused by: compile error: ; is missing
    at javassist.compiler.Parser.parseDeclarators(Parser.java:643)
    at javassist.compiler.Parser.parseDeclarationOrExpression(Parser.java:600)
    at javassist.compiler.Parser.parseFor(Parser.java:380)
    at javassist.compiler.Parser.parseStatement(Parser.java:279)
    at javassist.compiler.Parser.parseBlock(Parser.java:307)
    at javassist.compiler.Parser.parseStatement(Parser.java:261)
    at javassist.compiler.Parser.parseDo(Parser.java:351)
    at javassist.compiler.Parser.parseStatement(Parser.java:277)
    at javassist.compiler.Parser.parseBlock(Parser.java:307)
    at javassist.compiler.Parser.parseMethod2(Parser.java:172)
    at javassist.compiler.Javac.compileMethod(Javac.java:156)
    at javassist.compiler.Javac.compile(Javac.java:102)
    at javassist.CtNewMethod.make(CtNewMethod.java:79)
    ... 6 more