验证对静态外部类的私有静态嵌套类的非静态方法的调用

Question

How would I verify that a non-static method of a private nested class has been called? This is what I have so far:

new Verifications() {
    {
        Deencapsulation.invoke(MyClass.class.getDeclaredClasses()[0], "run" );
        times = 4;
    }
};

I'm getting this:

java.lang.IllegalArgumentException: Attempted to invoke non-static method without an instance to invoke it on...

Update 1:

@Dennis, I've tried the following, though I'm geting an NPE . I'd like to verify the running of the run method against the singleton that's already in the JVM, and not create a new instance of it (as I do in the code below) in order to invoke method m . I tried calling m.invoke(null) without success. Is there a way to verify the invocation (through it's invocation) in jmockit of a non-static method in a private nested class using reflection on the running instance of the outer class?

    new Verifications() {
        Class c = MyClass.class.getDeclaredClasses()[0];
        Method m = c.getDeclaredMethod("run");
        //Method m = MyClass.class.getDeclaredClasses()[0].getDeclaredMethod("run", Integer.class, CallableClient.class);

        //Deencapsulation.invoke(MyClass.class.getDeclaredClasses()[0], "run" );
        Class[] a = new Class[] { Integer.class, CallableClient.class};
        Object cc = Deencapsulation.newInstance(c, a);
        //Object cc = Deencapsulation.newInstance(c, withInstanceOf(Integer.class), withInstanceOf(CallableClient.class));
        {
            try {
                System.out.println(MyClass.class.getDeclaredClasses()[0].getName());
                m.invoke(cc);
                times = 3;

Update 2:

After trying unsuccessfully to get the method like this: final Field runnable = MyClass.class.getDeclaredField("nestedClassInstance"); runnable.setAccessible(true); final Field runnable = MyClass.class.getDeclaredField("nestedClassInstance"); runnable.setAccessible(true); and then using getDeclaredMethods() as well as getMethods() , i've decided that there's just too much wrong with this approach to continue with this. I've changed what I'm testing in my test. Even though I introduced an instance of the inner nested class, I'm assuming that the reason why I can't see the run method may be to do with one or all of: the nested nature of its containing class, constructors, and java's behavior/decision to not display instance methods until it could ensure the successful construction of the instance. Curious to know why I couldn't though, with certainty.

Answer 1

Since you said you wanted to find out if you're trying to invoke a non-static method at runtime, then this bit of reflection should help.

Assuming m is the Method instance corresponding to your method, then Modifier.isStatic(m.getModifiers()) will return true if and only if the method is static, so you can do this check before you actually call invoke . If you don't already have the Method object, then something like Class 's getMethod will be of use to you.

Docs on Method , Modifier , and Class .

---

EDIT: All of the above is helpful for checking whether or not the method is static before you call it via invoke . If you want to use something like jmockit to be able to find out that such a method has been called, then I'm personally wondering how that'll help the IllegalArgumentException that you're getting, especially if it's being thrown by invoke because you're trying to do what the exception message says is not allowed. Even if you could mock it out, that may be covering a deeper issue.