How to get the class of type variable in Java Generics

Question

I\'ve seen similar questions but they didnt help very much.

For instance I\'ve got this Generic Class:

public class ContainerTest
{

    public          


        

Answer 1

If you are interested in the reflection way, I found a partial solution in this great article: http://www.artima.com/weblogs/viewpost.jsp?thread=208860

In short, you can use java.lang.Class.getGenericSuperclass() and java.lang.reflect.ParameterizedType.getActualTypeArguments() methods, but you have to subclass some parent super class.

Following snippet works for a class that directly extends the superclass AbstractUserType. See the referenced article for more general solution.

import java.lang.reflect.ParameterizedType;


public class AbstractUserType {

    public Class returnedClass() {
        ParameterizedType parameterizedType = (ParameterizedType) getClass()
                .getGenericSuperclass();

        @SuppressWarnings("unchecked")
        Class ret = (Class) parameterizedType.getActualTypeArguments()[0];

        return ret;
    }

    public static void main(String[] args) {
        AbstractUserType myVar = new AbstractUserType() {};

        System.err.println(myVar.returnedClass());
    }

}