Question

I have a generic base class:

public class BaseLabel<T> extends JXLabel {
    private static final long serialVersionUID = 1L;

    public BaseLabel() {
        System.out.println(T.class.getClass().getName()); //error
    }       
}

and Child class:

public class ChildLabel extends BaseLabel<ChildLabel> {
    private static final long serialVersionUID = 2L;

    public ChildLabel() {

    }       
}

I am getting compilation error.

Is there any way to get the actual class name from the constructor of BaseClass. Here, by actual class I am referring to that class, which I am going to instantiate.

For example I am instantiating ChildClass, ChildClass clz = new ChildClass();

then that println() will print package.ChildClass.

Thanks in advance.

---

The compilation error is:

cannot select from a type variable System.out.println(T.class.getClass().getSimpleName());

---

If I call this.getClass.getSimpleName() from the abstract BaseClass‘s constructor. It is printing the ChildClass.

Why?

Is it due to, as I am instantiating ChildClass so this is pointing to the ChildClass‘s object.

Answer 1

Ugly? yes

import java.lang.reflect.ParameterizedType;


public class GenericClass<T> {

    public GenericClass() {
        System.out.println(getClass().getGenericSuperclass()); //output: GenericClass<Foo>
        System.out.println(((ParameterizedType)getClass().getGenericSuperclass()).getActualTypeArguments()[0]); //output: class Foo
    }

    public static void main(String[] args) {
        new ChildClass();
    }

}

child class

import java.lang.reflect.ParameterizedType;


public class ChildClass extends GenericClass<Foo> {

    public ChildClass() {
        System.out.println(((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0]); //output: class Foo
    }

}