大神们关于javassist 动态编译的问题

//ClassPool：CtClass对象的容器

ClassPool pool = ClassPool.getDefault();

    //通过ClassPool生成一个public新类Emp.java    
    CtClass ctClass = pool.makeClass("javassist.demo.MyCC");    



    //添加自定义方法    
    CtMethod ctMethod = new CtMethod(CtClass.voidType,"printInfo",new CtClass[]{},ctClass);    
    //为自定义方法设置修饰符    
    ctMethod.setModifiers(Modifier.PUBLIC);    
    //为自定义方法设置函数体    
    StringBuffer buffer2 = new StringBuffer();    
    buffer2.append("{\nSystem.out.println(\"begin!\");\n")    

            .append("}");    
    ctMethod.setBody(buffer2.toString());    
    ctClass.addMethod(ctMethod);    

            执行以下代码报错 
            ctClass.toClass(); 

            大神求解决

            Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
StackWalker cannot be resolved to a type
StackWalker cannot be resolved to a type
StackWalker cannot be resolved
StackWalker cannot be resolved to a variable
StackWalker cannot be resolved to a type
StackWalker cannot be resolved to a type
The method dropLookupMode(int) is undefined for the type MethodHandles.Lookup
The method defineClass(byte[]) is undefined for the type MethodHandles.Lookup

at javassist.util.proxy.DefineClassHelper$SecuredPrivileged$3.<init>(DefineClassHelper.java:53)
at javassist.util.proxy.DefineClassHelper$SecuredPrivileged.<clinit>(DefineClassHelper.java:38)
at javassist.util.proxy.DefineClassHelper.<clinit>(DefineClassHelper.java:177)
at javassist.ClassPool.toClass(ClassPool.java:1120)
at javassist.ClassPool.toClass(ClassPool.java:1083)
at javassist.ClassPool.toClass(ClassPool.java:1041)
at javassist.CtClass.toClass(CtClass.java:1278)
at javassist.demo.GenerateNewClassByJavassist.main(GenerateNewClassByJavassist.java:46)

stackwalker是个第三方类
不知道你说的是不是这个
http://blog.sina.com.cn/s/blog_648d306d0100qmca.html