Find common elements among two unsorted arrays


Sometimes, you may face this situation that you have 2 arrays and both are unsorted. You need to compare them and find out the common values. How to find out common elements in 2 unsorted arrays?

Suppose, you are extracting data from Database as well as from front end Application. Now, you need to compare the data extracted from both the sources.Let’s see with an example.

In the example below, we have 2 Integer arrays which are having some values. There are following steps which you will perform to complete the job.


  • Compare the length of both the array and find the small one.
  • Iterate through small array and put unique values in a HashSet.
  • Iterate through large array and find the elements stored in the previous Hashset.
  • If find common value, add to a new array.
  • Display final array.

Common Elements Between Two Arrays: 4 5

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Shekhar Sharma

Shekhar Sharma

Shekhar Sharma is founder of This website is his window to the world. He believes that ,"Knowledge increases by sharing but not by saving".

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1 Response

  1. August 31, 2015

    […] the previous post, we have seen how to find common elements among 2 unsorted arrays. In this post, we will see how to get the count of same word occurrences in a […]

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