Reflection - Getting different results from HashMap - LinkedHashMap

I'll keep it brief, I have a Dog class like the following:

public class Dog 
{
   public void Foo() 
   { 
      System.out.println("Right Call");
   }

   public void Boo()
   {
     System.out.println("Wrong Call");
   }
}

and a main method like following:

HashMap<String, Method> map = new HashMap<String, Method>();

Dog d = new Dog();

Method[] method = d.getClass().getMethods();

map.put("foo", method[0]);

Method a = map.get("foo");

try {
    a.invoke(d, null);
} catch (IllegalAccessException | IllegalArgumentException
        | InvocationTargetException e) {
    e.printStackTrace();
}

Whenever I run it again, it just arbitrarily gives Right Call or Wrong Call outputs.

I need to be sure that every time I place the "foo" key, It must to be calling the Foo() method, instead of Boo().

Apparently, It doesn't ease my "method call" problem. How can I overcome this issue? I must be calling the right method every time. I'm quite new to this reflections stuff, is there anything that I shouldn't be doing, or something that I'm doing wrong? Or is there a better way to implement this method calling?

EDIT: I've also tried LinkedHashMap, however, the result is the same.

Thank you.