Remove duplication from array – Java

A question was posted on the forum where a user had an array and wanted to remove the duplication. The user was attempting to use the System.arraycopy() method for some reason, which was a shame because most of the code they had written appeared to be in place.


Two fold really. Firstly I started with creating a new array to copy elements into, but then realised afterwards that I couldn’t declare the size of the new array as I didn’t know how many duplicate items were going to be removed. (I also experienced a crash in my browser whilst writing this blog post and have now subsequently lost that code! – if anyone if desperate for it, it’ll take a few minutes to post back up). However, rather than declaring a new array, a simple ArrayList would have sufficed, until…

Having read the answers to the original question, someone recommended using Sets, so I did a little reading around these. This produced a much nicer solution:

char[] myArray = new char[6];
myArray[0] = 'g';
myArray[1] = 'j';
myArray[2] = 'a';
myArray[3] = 'g';
myArray[4] = 'x';
myArray[5] = 'y';

Set resultSet = new HashSet();

for (int i = 0; i < myArray.length; i++) {
   if (!resultSet.add(myArray[i]))
       System.out.println("Duplicated detected: " + myArray[i]);


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