Java set of byte arrays

Question

I have a HashSet of byte[]s and I would like to test whether a new byte[] is in that set. The problem is that Java seems to be testing whether the byte[] instances are the same rather than testing whether the actual values in the byte arrays are the same.

In other words, consider the following code:

public class Test
{
    public static void main(String[] args)
    {
        java.util.HashSet<byte[]> set=new java.util.HashSet<byte[]>();
        set.add(new String("abc").getBytes());
        System.out.println(set.contains(new String("abc").getBytes()));
    }
}

This code prints out false and I would like it to print out true. How should I go about doing this?

Answer 1

You can wrap each byte array using ByteBuffer.wrap, which will provide the right equals and hashCode behavior for you. Just be careful what methods you call on the ByteBuffer (that you don't modify the array or advance its pointer).