Java Reflection without qualified name

Question

I am trying to do Java Reflection using Class c = Class.forName(className)

I want to pass in the className without specifying the package n

Answer 1

First, get all classes with the Reflections library

 Reflections reflections = new Reflections();

 Set> allClasses = reflections.getSubTypesOf(Object.class);

Next, build up a lookup-map.

// Doesn't handle collisions (you might want to use a multimap such as http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/collect/Multimap.html instead)
Map> classBySimpleName = new HashMap<>();

for(Class c : allClasses) {
    classBySimpleName.put(c.getSimpleName(), c);         
}

When you need to lookup a class you'll do:

Class clazz = classBySimpleName.get(className);