TypeBuilder builds parameterized Java Class references.

TypeBuilder.java

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

/**
 * <p>TypeBuilder builds parameterized {@code Class<?>} references. Example:</p>
 * <pre>
 * {@code
 * Class<List<String>> type = new TypeBuilder<List<String>>() { }.build();
 * }
 * </pre>
 */
public abstract class TypeBuilder<T> {
    public Class<T> build() {

		Type superclass = getClass().getGenericSuperclass();
		if (superclass instanceof Class) {
			throw new RuntimeException("Missing type parameter.");
		}
		ParameterizedType parameterized = (ParameterizedType) superclass;
		return convert(parameterized.getActualTypeArguments()[0]);
	}

	@SuppressWarnings("unchecked")
	private Class<T> convert(Type type) {
		if (type instanceof Class) {
			return (Class<T>) type;
		} else if (type instanceof ParameterizedType) {
			ParameterizedType parameterizedType = (ParameterizedType) type;
			Type rawType = parameterizedType.getRawType();
			return (Class<T>) rawType;
		} else {
			return null;
		}
	}
}