My name
is
Jon Skeet

Compare Object superclass package with Object package

I'm trying to check if an object has a superclass in the same package.

I made the following example

Vehicle.java

package myPackage;

public class Vehicle {
    public Vehicle(){}
}

Car.java

package myPackage;

public class Car extends Vehicle{
    public Car(){
        super();
    }

}

Main.java

1 package myPackage;
2
3 public class Main {
4
5    public static void main(String[] args){
6       Vehicle v = new Car();
7       hasSuperInSamePackage(v);
8    }
9
10   public static boolean hasSuperInSamePackage(Object o) {
11      boolean b = false;
12      if ((o.getClass().getSuperclass()) != null) {
13      
14          Class c = o.getClass().getSuperclass();
15          Package objectPackage = o.getClass().getPackage();
16          Package superPackage = c.getClass().getPackage();
17          System.out.println("--begin--");
18          System.out.println("Object: " + o.toString());
19          System.out.println("objectPackageName: " + objectPackage.getName());
20          System.out.println("Super: " + c.toString());
21          System.out.println("superPackageName: " + superPackage.getName());
22          System.out.println("---end---");
23  
24          b = (superPackage.getName().equals(objectPackage.getName()));
25     }
26     return b;
27   }
28 }

The output of the main is the following

--begin--
Object: myPackage.Car@7852e922
objectPackageName: myPackage
Super: myPackage.Vehicle
superPackageName: java.lang
---end---

As you can see the c.getClass()[Main.16] takes the superclass of the class Class which is java.lang which is quite obvious. I want to get "myPackage" as the superclass. How do I do this?

You're calling c.getClass().getPackage() when you should be calling c.getPackage(). c is already the superclass - it's a Class, so calling getClass() on it will just give you Class.class, which isn't what you want.

I would try to be more consistent about it, like this:

Class objectClass = o.getClass();
Class superClass = thisClass.getSuperclass();
Package objectPackage = objectClass.getPackage();
Package superPackage = superClass.getPackage();
System.out.println("--begin--");
System.out.println("Object: " + objectClass);
System.out.println("objectPackageName: " + objectPackage.getName());
System.out.println("Super: " + superClass);
System.out.println("superPackageName: " + superPackage.getName())

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