java.util.Collections.copy() Method


Advertisements


Description

The copy(List<? super T>, List<? extends T>) method is used to copy all of the elements from one list into another.

Declaration

Following is the declaration for java.util.Collections.copy() method.

public static <T> void copy(List<? super T> dest,List<? extends T> src)

Parameters

  • dest -- This is the destination list.

  • src -- This is the source list.

Return Value

  • NA

Exception

  • IndexOutOfBoundsException -- This is thrown if the destination list is too small to contain the entire source List.

  • UnsupportedOperationException -- This is thrown if the destination list's list-iterator does not support the set operation.

Example

The following example shows the usage of java.util.Collections.copy()

package com.tutorialspoint;

import java.util.*;

public class CollectionsDemo {
   public static void main(String args[]) {
   // create two lists    
   List<String> srclst = new ArrayList<String>(5);
   List<String> destlst = new ArrayList<String>(10);
      
   // populate two lists
   srclst.add("Java");
   srclst.add("is");
   srclst.add("best");
      
   destlst.add("C++");
   destlst.add("is");
   destlst.add("older");
      
      
   // copy into dest list
   Collections.copy(destlst, srclst);            
      
   System.out.println("Value of source list: "+srclst);
   System.out.println("Value of destination list: "+destlst);
   }    
}

Let us compile and run the above program, this will produce the following result.

Value of source list: [Java, is, best]
Value of destination list: [Java, is, best]

java_util_collections.htm

Advertisements