A simple generic class

[Java Tip]

Code:

// Here, T is a type parameter that will be replaced by a real type 
// when an object of type Gen is created. 
class Gen<T> { 
  T ob; // declare an object of type T 
  // Pass the constructor a reference to  
  // an object of type T. 
  Gen(T o) { 
    ob = o; 
  } 
  // Return ob. 
  T getob() { 
    return ob; 
  } 
  // Show type of T. 
  void showType() { 
    System.out.println("Type of T is " + 
                       ob.getClass().getName()); 
  } 
} 
//Demonstrate the generic class. 
public class GenDemo { 
  public static void main(String args[]) { 
    // Create a Gen reference for Integers.  
    Gen<Integer> iOb;  
    // Create a Gen<Integer> object and assign its 
    // reference to iOb.  Notice the use of autoboxing  
    // to encapsulate the value 88 within an Integer object. 
    iOb = new Gen<Integer>(88); 
    // Show the type of data used by iOb. 
    iOb.showType(); 
    // Get the value of in iOb. Notice that 
    // no cast is needed. 
    int v = iOb.getob(); 
    System.out.println("value: " + v); 
    System.out.println(); 
    // Create a Gen object for Strings. 
    Gen<String> strOb = new Gen<String>("Generics Test"); 
    // Show the type of data used by strOb. 
    strOb.showType(); 
    // Get the value of strOb. Again, notice 
    // that no cast is needed. 
    String str = strOb.getob(); 
    System.out.println("value: " + str); 
  } 
}