java.util.Collections.indexOfSubList() Method

---

Description

The indexOfSubList(List<?>, List<?>) method is used to get the starting position of the first occurrence of the specified target list within the specified source list.

Declaration

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

public static int indexOfSubList(List<?> source, List<?> target)

Parameters

• source − This is the list in which to search for the first occurrence of target.

• target − This is the list to search for as a subList of source.

Return Value

The method call returns the starting position of the first occurrence of the specified target list within the specified source list, or -1 if there is no such occurrence.

Exception

NA

Example

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

package com.tutorialspoint;

import java.util.*;

public class CollectionsDemo {
   public static void main(String args[]) {

      // create two array list objects       
      List arrlistsrc = new ArrayList();
      List arrlisttarget = new ArrayList();

      // populate two lists
      arrlistsrc.add("A");
      arrlistsrc.add("B");
      arrlistsrc.add("C");
      arrlistsrc.add("D");
      arrlistsrc.add("E"); 

      arrlisttarget.add("C");
      arrlisttarget.add("D");
      arrlisttarget.add("E");

      // check target list in source list
      int index = Collections.indexOfSubList(arrlistsrc, arrlisttarget);

      System.out.println("Target list starts at index: "+index);    
   }    
}

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

Target list starts at index: 2