List indexOf() Method in Java with Examples

This method returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.

Example:

Index of GFG is 2

Syntax of Method

public int indexOf(Object o)

Parameters: This function has a single parameter, i.e, the element to be searched in the list.

Returns: This method returns the index of first occurrence of the given element in the list and returns "-1" if element is not in the list.

Example of List indexOf() Method

Below programs show the implementation of this method.

Program 1:

[1, 3, 5, 7]
2

Program 2:

Below is the code to show implementation of list.hashCode() using Linkedlist.

[10, 15, 20]
2

Reference: Oracle Docs