java反射：getMethods函数没有显示方法

Question

import java.lang.reflect.Method;
import java.util.Arrays;

public class Test
{
     public static void main(String s[]) throws ClassNotFoundException
     {
        Class cls = Class.forName("Test");
        System.out.println("Class is "+cls);
        Method[] mtds = cls.getMethods();
        System.out.println("Methods are "+Arrays.deepToString(mtds));  // not having all methods
    }

    void reflectionTestMethod()
    {
        System.out.println("test");
    }
}

Output is

Class is class Test

Methods are [public static void Test.main(java.lang.String[]) throws java.lang.ClassNotFoundException, public final void java.lang.Object.wait() throws java.lang.InterruptedException, public final native void java.lang.Object.wait(long) throws java.lang.InterruptedException, public final void java.lang.Object.wait(long,int) throws java.lang.InterruptedException, public boolean java.lang.Object.equals(java.lang.Object), public java.lang.String java.lang.Object.toString(), public native int java.lang.Object.hashCode(), public final native java.lang.Class java.lang.Object.getClass(), public final native void java.lang.Object.notify(), public final native void java.lang.Object.notifyAll()]

Why is reflectionTestMethod() not available in the output ?

Answer 1

getMethods() returns public methods (as it states in its Javadoc)

Try getDeclaredMethods() instead or make the method public.

BTW, you can do:

Class cls = Test.class;
System.out.println("Class is " + cls);
for(Method method : cls.getDeclaredMethods())
    System.out.println(method);

Answer 2

Because that method is not public. The javadoc states (emphasis mine):

Returns an array containing Method objects reflecting all the public member methods of the class or interface represented by this Class object