Java Reflection, getMethod()

Question

I'm working with the basics of Java reflection and observing information on methods of classes. I need to get a method that matches specifications as described by the getMethod() function. However, when I do this I get a NoSuchMethodException, and I was hoping you could tell me why my implementation is incorrect.

static void methodInfo2(String className) throws ClassNotFoundException, 

NoSuchMethodException{

        Class cls = null;
        try{
            cls = Class.forName(className);
        } catch(ClassNotFoundException e){
            e.printStackTrace();
        }
        System.out.println("Cls:  "+cls);


        Method method1 = cls.getMethod("test", null);
        System.out.println("method1:  "+method1);


    }

EDIT1:When I print out "Cls: "+cls, the output is "Cls: class a8.myclass2". Why does it append the class part? (the a8 is correct, so don't worry about that) /EDIT1

This is the function I use to read in a class from my main function, and then I want to getMethod() with the parameters "test" and null, where "test" is the name of the method and null means the method has no parameters. The class I am reading in is called myclass2 which is here:

package a8;

public class myclass2 {

    void test(){
        //"takes no parameters"
        //"returns bool"
        //"name starts with test"
        //return true;
    }

}

As you can see, the method does infact exist in the class. If you could point out my mistake, I would really appreciate it.

Todd · Accepted Answer · 2011-12-02 17:58:57Z

8

Make your test method public. I believe Class.getMethod() is limited to public methods.

answered Dec 2, 2011 at 17:58

Todd

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1 Comment

Brandon Buck Over a year ago

It does, and you beat me to it. +1 From the JavaDoc for getMethod(): "Returns a Method object that reflects the specified public member method of the class or interface represented by this Class object."

jli · Accepted Answer · 2011-12-02 18:01:05Z

3

Without you posting the exact exception and your output, its hard to tell, but I suspect it is because the classes are in two separate packages, and since the default modifiers for a method are just protected it fails.

Use getDeclaredMethod() to get a method that isn't normally visible.

answered Dec 2, 2011 at 18:01

jli

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2 Comments

Nibirue Over a year ago

Nope, they were within the same package. The answer above worked though.

jli Over a year ago

Might default to private then. Either way, if you use getDeclaredMethod() you can access anything.

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