Here is a fun quiz: What is the best possible way (fastest with least memory) to convert an int to a byte array (of size 4) in big endian in Java ? ie.

public static byte[] toBigEndianBytes(int i) {
// ??
}

It turns out the code below is the best I've found so far:

public static byte[] toBigEndianBytes(int i) {
        return new byte[] {
                (byte)(i >>> 24), 
                (byte)(i >>> 16),
                (byte)(i >>> 8),
                (byte)i
        };
}

Can you think of a better one ?

Update on 21Mar06: Interesting class to look at java.nio.Bits.
Update on 29Mar06: Paul Brown has more details.