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Comparing two ArrayList In Java

Last Updated : 07 Oct, 2022
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Java provides a method for comparing two Array List. The ArrayList.equals() is the method used for comparing two Array List. It compares the Array lists as, both Array lists should have the same size, and all corresponding pairs of elements in the two Array lists are equal.

Example:

Input : ArrayList1 = [1, 2, 3, 4],
        ArrayList2 = [1, 2, 3, 4]
Output: Array List are equal

Input : ArrayList1 = [1, 2, 3, 4],
        ArrayList2 = [4, 2, 3, 1]
Output: Array List are not equal

Syntax:

boolean equals(Object o)

Parameters: This function has a single parameter which is an object to be compared for equality.

Returns: This method returns True if Array lists are equal.

Implementation:


Output
 ArrayList1 = [item 1, item 2, item 3, item 4]
 ArrayList1 = [item 1, item 2, item 3, item 4]
 Array List are equal

 Lets insert one more item in Array List 1
 ArrayList1 = [item 1, item 2, item 3, item 4, item 5]
 ArrayList = [item 1, item 2, item 3, item 4]
 Array List are not equal

Time Complexity: O(N), where N is the length of the Array list.


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