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Stack lastIndexOf(Object, int) method in Java with Example

Last Updated : 24 Dec, 2018
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The Java.util.Stack.lastIndexOf(Object element, int last_index) method is used to the last index of the first occurrence of the specified element in this Stack, searching forwards from last index, or returns -1 if the element is not found. More formally, returns the lowest last index i such that (i >= last index && Objects.equals(o, get(i))), or -1 if there is no such last index. Syntax: 
public int lastIndexOf(Object element, int last_index)
Parameters: This method accepts two parameters:
  • element of the type of Stack. It specifies the element whose occurrence is needed to be checked in the Stack.
  • last index of the type Integer. It specifies the last index to start searching from
Return Value: This method returns the last index or position of the first occurrence of the element in the Stack from the specified last index. Else it returns -1 if the element is not present in the Stack. The returned value is of integer type. Exception: This method throws IndexOutOfBoundsException if the specified index is greater than or equal to the current size of this vector Below programs illustrate the Java.util.Stack.lastIndexOf() method: Program 1: Java 
// Java code to illustrate lastIndexOf() import java.util.*; public class StackDemo {  public static void main(String args[])  {  // Creating an empty Stack  Stack<String> stack = new Stack<String>();  // Use add() method to add elements in the Stack  stack.add("Geeks");  stack.add("for");  stack.add("Geeks");  stack.add("10");  stack.add("Geeks");  // Displaying the Stack  System.out.println("Stack: " + stack);  // The first position of an element  // is returned  System.out.println("The first occurrence"  + " of Geeks is at last index:"  + stack.indexOf("Geeks"));  // Get the last occurrence of Geeks  // using lastIndexOf() method  System.out.println("The last occurrence"  + " of Geeks is at last index: "  + stack  .lastIndexOf("Geeks",  stack.lastIndexOf("Geeks")));  } }
Output: 
 Stack: [Geeks, for, Geeks, 10, Geeks] The first occurrence of Geeks is at last index:0 The last occurrence of Geeks is at last index: 4
Program 2: To demonstrate IndexOutOfBoundsException Java 
// Java code to illustrate lastIndexOf() import java.util.*; public class StackDemo {  public static void main(String args[])  {  // Creating an empty Stack  Stack<Integer> stack = new Stack<Integer>();  // Use add() method to add elements in the Stack  stack.add(1);  stack.add(2);  stack.add(3);  stack.add(10);  stack.add(20);  // Displaying the Stack  System.out.println("Stack: " + stack);  // Get the 10th occurrence of Geeks  // using lastIndexOf() method  System.out.println("The 10th occurrence"  + " of Geeks is at index: ");  try {  stack.lastIndexOf("Geeks", 10);  }  catch (Exception e) {  System.out.println(e);  }  } }
Output: 
 Stack: [1, 2, 3, 10, 20] The 10th occurrence of Geeks is at index: java.lang.IndexOutOfBoundsException: 10 >= 5

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