CODEWITHSUNDEEP
javaclassinheritanceparameterssubclassing
user1908813
user1908813

Reputation: 43

java referencing Class<> as their subtype

I am trying to do something like this....

public class myClass2 extends myClass1
{
    @Override
     public void printStuff() { }
}

public class dostuff
{

   public dostuff() 
   {
        doSomething(myClass2.Class());
   }

   public void doSomething(Class<myClass1> cls)
   {
        cls.printStuff();
   }
}

Im getting compile errors like this

Required: myClass1 Found: myClass2

How can I tell the function to except subclasses of myClass1?

Upvotes: 0

Views: 46

Answers (1)

Eran
Eran

Reputation: 393811

public void doSomething(Class<? extends myClass1> cls) 
{
    try {
      cls.newInstance().printStuff();
    } catch (InstantiationException e) {
      ....
    } catch (IllegalAccessException e) {
      ....
    }
}

  1. To let the method expect sub-classes of myClass1, you have to use a bounded type parameter.

  2. You have to create an instance of the class in order to call the method printStuff().

You also have an error in dostuff. It should be :

   public void dostuff() 
   {
        doSomething(myClass2.class);
   }

Upvotes: 1

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