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How to create Generic Type specific Collections in Java ?

Program to demonstrate how we can create Generic Type specific Collections in Java

package com.hubberspot.example;

import java.util.ArrayList;

public class GenericTypeSafeCollections {
 
   public static void main(String[] args) {
  
   // Raw type ArrayList compiler throws warning
   // this collection is not type safe 
 ArrayList list = new ArrayList();
   // Anything can go in the ArrayList declared
   // as raw type 
 list.add(1); // Integer
 list.add("Jonty"); // String
 list.add(1.2f); // Float
 list.add(new Object()); // Object
 list.add(new String[]{ "Raw" , "Type"}); // String Array
  
   // When we retrieve elements from raw type we can get wrong 
   // element that we did not expect so everytime we get is the 
   // raw Object that we have to typecast in order to get our 
   // required type ... 
 Integer i = (Integer)list.get(1); // casting required
 String s = (String)list.get(2); // casting required
  
  
   // To make Type Safe and specific collections we use generics
   // Lets see demo below 
  
 ArrayList< String > genericList = new ArrayList< String >();
 genericList.add("Jonty");
 genericList.add("Magicman");
 genericList.add(1); // Compiler error only Strings allowed
 genericList.add(1.2f); // Compiler error only Strings allowed
  
   // When we retrieve elements from generic type we will only get 
   // right element that we expect, so everytime we get is the 
   // generic String. We dont have to typecast because compiler knows 
   // that collection will have only String in it ...
  
 String gs = genericList.get(0);
 String gss = genericList.get(1);

   }

}




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