Event Manager Not Invoking (Java)

So this is the first time I'm writing a proper event manager but for some reason my method which calls and invokes the stored keys/values throws a NullPointerException even though I added the class and method data to the map in my register method.

My calling method:

public static final void fire(final Event event) {
        final Class<? extends Event> clazz = event.getClass();
        final List<EventListener> listeners = eventMap.get(clazz);
        if(listeners != null) {
            for(EventListener listener : listeners) {
                try {
                    listener.getMethod().invoke(listener.getObject(), event);
                } catch (InvocationTargetException e) {
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
        }
    }

And this is where I register/unregister my events:

    public static final void register(Object o) {
        Class clazz = o.getClass();
        Method[] methods = clazz.getDeclaredMethods();
        for(Method m : methods) {
            final Handler handler = m.getAnnotation(Handler.class);
            if(handler == null) continue;
            if(!m.isAccessible())
                m.setAccessible(true);
               if(!eventMap.containsKey(clazz) && m.getParameterTypes()[0].equals(clazz)) {
                   eventMap.put(clazz, new LinkedList<EventListener>());
               }
        }
    }

    public static final void unregister(Object o) {
        Class clazz = o.getClass();
        Method[] methods = clazz.getDeclaredMethods();
        for(Method m : methods) {
            if(eventMap.containsKey(clazz)) {
                final List<EventListener> listener = eventMap.get(clazz);
                eventMap.remove(clazz, listener);
            }
        }

Any help would be greatly appreciated.

Update: Here's the stacktrace when I remove the != null check.

java.lang.NullPointerException: Unexpected error
        at me.jamie.lib.event.EventManager.fire(EventManager.java:49)
        at me.jamie.revolution.gui.RevolutionUI.func_175180_a(RevolutionUI.java:25)

Like I said, the register/unregister methods run without a problem, but when I initiate the fire method it seems to consider the map as empty.