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Thread: Generics

  1. #1
    sireesha is offline Member
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    Question Generics

    Hi,
    I am placing some code here...
    Java Code:
    public class GenericBox1
    {
       public <U> void inspect(U u)
       {
           System.out.println(u.getClass().getName());
       }        
       public static void main(String[] args)
       {
         GenericBox1 ob=new GenericBox1();
         System.out.println("Passing Integer object");
         ob.inspect(new Integer(10));
         System.out.println("Passing Double object");
         ob.inspect(10.34); //..............see this line                            
         System.out.println("Passing String object");
         ob.inspect("affaffaf");
         Integer intobject=new Integer(24);
         System.out.println("Passing Integer object");
         ob.inspect(intobject);
       }
        }
    In my code i am passing a primitive type 10.34 instead of a object.
    But i read that we can't pass primitive types as a formal type parameter in generics use.
    But here i did it.
    but it didn't show any error.it works well.
    what is the reason for this ?
    is this the example for auto boxing and unboxing ?

  2. #2
    roots's Avatar
    roots is offline Moderator
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    Default

    Yes this is an example of Autoboxing and unboxing ..
    can't pass primitive types as a formal type parameter in generics use
    Java Code:
    public class Box<E> {
    	private E e;
    
    	public E getE() {
    		return e;
    	}
    
    	public void setE(E e) {
    		this.e = e;
    	}
    
    	public static void main(String[] args) throws Exception {
    		Box<Integer> ok = new Box<Integer>();		
    		Box<int> no-ok = new Box<int>(); // This doesnot work
    	}
    }
    dont worry newbie, we got you covered.

  3. #3
    sireesha is offline Member
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