java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType

Question

I have created hierarchy of interface and classes using generic and messed up everything.
Topmost class is AbstractJpaEntity which is extended by all domain entity

Answer 1

This is a solution

public TO getTo() throws Exception {
    if(to == null) {
        try {
            to = ((Class<TO>) ((ParameterizedType) this.getClass().getGenericSuperclass())
                    .getActualTypeArguments()[0]).newInstance();
        } catch(ClassCastException cce) {
            cce.printStackTrace();
            to = ((Class<TO>) ((ParameterizedType) (((Class<TO>) this.getClass()
                    .getAnnotatedSuperclass().getType()).getGenericSuperclass()))
                            .getActualTypeArguments()[0]).newInstance();
        }
    }
    return to;
}

Answer 2

In this class declaration

public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao

you're using GenericDaoImpl and ProductTypeDao as raw types. Start by reading why you shouldn't use them.

The fact that you are using raw types causes problems here

ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();

where getGenericSuperclass() will return a Class instance since GenericDaoImpl, in

public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao

is not parameterized and therefore isn't a ParameterizedType. The cast then fails.

The solution is to parameterize the two types in your class declaration. It's not immediately obvious from your code what those type arguments should be, but GenericTypeDao should probably take ProductTypeDomain

public class ProductTypeDaoImpl extends GenericDaoImpl<ProductTypeDomain> implements ProductTypeDao

and your interface ProductTypeDao should probably be declared as

public interface ProductTypeDao extends GenericDao<ProductTypeDomain> {