Casting within a generic class hierarchy : Generic Class Hierarchies « Generics « Java Tutorial

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Java Tutorial » Generics » Generic Class Hierarchies   12. 7. 5. Casting within a generic class hierarchy You can cast one instance of a generic class into another only if the two are otherwise compatible and their type arguments are the same. class Gen<T> {     T ob;         Gen(T o) {       ob = o;     }        T getObject() {       return ob;     }   }     class Gen2<T> extends Gen<T> {    Gen2(T o) {      super(o);    }  }    public class MainClass {     public static void main(String args[]) {       Gen<Integer> intObject = new Gen<Integer>(88);      Gen2<Long> longObject = new Gen2<Long>(99L);         //longObject = (Gen2<Long>)intObject;     }   } 12. 7. Generic Class Hierarchies 12. 7. 1.  Generic Class Hierarchies: uses a generic superclass 12. 7. 2.  A subclass can add its own type parameters, if needed. 12. 7. 3.  A Generic Subclass: a nongeneric class can be the superclass of a generic subclass 12. 7. 4.  Run-Time Type Comparisons Within a Generic Hierarchy 12. 7. 5.  Casting within a generic class hierarchy 12. 7. 6.  Overriding Methods in a Generic Class

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