[java] Compare two Byte Arrays? (Java)

I have a byte array with a ~known binary sequence in it. I need to confirm that the binary sequence is what it's supposed to be. I have tried .equals in addition to ==, but neither worked.

byte[] array = new BigInteger("1111000011110001", 2).toByteArray();
if (new BigInteger("1111000011110001", 2).toByteArray() == array){
    System.out.println("the same");
} else {
    System.out.println("different'");
}

Check out the static java.util.Arrays.equals() family of methods. There's one that does exactly what you want.

Of course, the accepted answer of Arrays.equal( byte[] first, byte[] second ) is correct. I like to work at a lower level, but I was unable to find a low level efficient function to perform equality test ranges. I had to whip up my own, if anyone needs it:

public static boolean ArraysAreEquals(
 byte[] first,
 int firstOffset,
 int firstLength,
 byte[] second,
 int secondOffset,
 int secondLength
) {
    if( firstLength != secondLength ) {
        return false;
    }

    for( int index = 0; index < firstLength; ++index ) {
        if( first[firstOffset+index] != second[secondOffset+index]) {
            return false;
        }
    }

    return true;
}

You can use both Arrays.equals() and MessageDigest.isEqual(). These two methods have some differences though.

MessageDigest.isEqual() is a time-constant comparison method and Arrays.equals() is non time-constant and it may bring some security issues if you use it in a security application.

The details for the difference can be read at Arrays.equals() vs MessageDigest.isEqual()

Java doesn't overload operators, so you'll usually need a method for non-basic types. Try the Arrays.equals() method.

Since I wanted to compare two arrays for a unit Test and I arrived on this answer I thought I could share.

You can also do it with:

@Test
public void testTwoArrays() {
  byte[] array = new BigInteger("1111000011110001", 2).toByteArray();
  byte[] secondArray = new BigInteger("1111000011110001", 2).toByteArray();

  Assert.assertArrayEquals(array, secondArray);
}

And you could check on Comparing arrays in JUnit assertions for more infos.