CopyOnWriteArrayList lastIndexOf() method in Java
Last Updated :
31 May, 2023
The lastIndexOf(Object o) method of CopyOnWriteArrayList returns the last occurrence of the element passed in the list. It returns -1 if the element is not present in the list.
Syntax:
public int lastIndexOf(Object o)
Parameters: The function accepts a parameter o whose last occurrence is to be returned.
Return Value: The function returns the last occurrence of the element. It returns -1 if the element is not present in the list.
Below programs illustrate the above function:
Program 1:
Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
CopyOnWriteArrayList<Integer> ArrLis
= new CopyOnWriteArrayList<Integer>();
ArrLis.add( 32 );
ArrLis.add( 67 );
ArrLis.add( 67 );
ArrLis.add( 100 );
System.out.println("CopyOnWriteArrayList: "
+ ArrLis);
System.out.println("lastIndexOf value: "
+ ArrLis.lastIndexOf( 67 ));
}
}
|
Output:
CopyOnWriteArrayList: [32, 67, 67, 100]
lastIndexOf value: 2
Program 2:
Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
CopyOnWriteArrayList<Integer> ArrLis
= new CopyOnWriteArrayList<Integer>();
ArrLis.add( 32 );
ArrLis.add( 67 );
ArrLis.add( 67 );
ArrLis.add( 100 );
System.out.println("CopyOnWriteArrayList: "
+ ArrLis);
System.out.println("lastIndexOf value: "
+ ArrLis.lastIndexOf( 200 ));
}
}
|
Output:
CopyOnWriteArrayList: [32, 67, 67, 100]
lastIndexOf value: -1
The lastIndexOf(E e, int index) method of CopyOnWriteArrayList returns the last occurrence of the element passed in the list after position index. It returns -1 if the element is not present in the list.
Syntax:
public int lastIndexOf(E e, int index)
Parameters: The function accepts two parameters which are described below:
- index: specifies the index from which the occurrence is to be searched.
- e: specifies the element whose last occurrence from position index is to be returned.
Return Value: The function returns the last occurrence of the element after position index. It returns -1 if the element is not present in the list.
Exceptions: The function throws an IndexOutOfBoundsException if the specified index is negative.
Below programs illustrate the above function:
Program 1:
Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
CopyOnWriteArrayList<Integer> ArrLis
= new CopyOnWriteArrayList<Integer>();
ArrLis.add( 32 );
ArrLis.add( 67 );
ArrLis.add( 67 );
ArrLis.add( 67 );
System.out.println( "CopyOnWriteArrayList: "
+ ArrLis);
System.out.println( "lastIndexOf value: "
+ ArrLis.lastIndexOf( 67 , 2 ));
}
}
|
Output:
CopyOnWriteArrayList: [32, 67, 67, 67]
lastIndexOf value: 2
Program 2:
Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
CopyOnWriteArrayList<Integer> ArrLis
= new CopyOnWriteArrayList<Integer>();
ArrLis.add( 32 );
ArrLis.add( 67 );
ArrLis.add( 67 );
ArrLis.add( 100 );
System.out.println( "CopyOnWriteArrayList: "
+ ArrLis);
System.out.println( "lastIndexOf value: "
+ ArrLis.lastIndexOf(- 1 , 200 ));
}
}
|
Output:
Exception in thread “main” java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.concurrent.CopyOnWriteArrayList.lastIndexOf(CopyOnWriteArrayList.java:198)
at java.util.concurrent.CopyOnWriteArrayList.lastIndexOf(CopyOnWriteArrayList.java:263)
at GFG.main(GFG.java:24)
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