This may be a crazy idea but its an idea :).

• First generate UUID and get a string representation of it with java.util.UUID.randomUUID().toString()

• Second convert generated string to byte array (byte[])

• Then convert it to long buffer: java.nio.ByteBuffer.wrap( byte digest[] ).asLongBuffer().get()

• Truncate to 10 digits

Not sure about uniqueness of that approach tho, I know that you can rely on uniqueness of UUIDs but haven't checked how unique are they converted and truncated to 10 digits long number.

Example was taken from JavaRanch, maybe there is more.

Edit: As you are limited to 10 digits maybe simple random generator would be enough for you, have a look into that quesion/answers on SO: Java: random long number in 0 <= x < n range

If you want short, human-readable IDs and only need them to be unique per JVM run:

private static long idCounter = 0;

public static synchronized String createID()
{
    return String.valueOf(idCounter++);
}    

Edit: Alternative suggested in the comments - this relies on under-the-hood "magic" for thread safety, but is more scalable and just as safe:

private static AtomicLong idCounter = new AtomicLong();

public static String createID()
{
    return String.valueOf(idCounter.getAndIncrement());
}

I think the reason you're getting 8/9 digit values and negative numbers is that you're adding fraction, a long (signed 64-bit value) which may be larger than the positive int range (32-bit value) to aStart.

The value is overflowing such that randomNumber is in the negative 32-bit range or has almost wrapped around to aStart (since int is a signed 32-bit value, fraction would only need to be slightly less than (2^32 - aStart) for you to see 8 or 9 digit values).

You need to use long for all the values.

   private static void createRandomInteger(int aStart, long aEnd, Random aRandom){
    if ( aStart > aEnd ) {
      throw new IllegalArgumentException("Start cannot exceed End.");
    }
    //get the range, casting to long to avoid overflow problems
    long range = aEnd - (long)aStart + 1;
    logger.info("range>>>>>>>>>>>"+range);
    // compute a fraction of the range, 0 <= frac < range
    long fraction = (long)(range * aRandom.nextDouble());
    logger.info("fraction>>>>>>>>>>>>>>>>>>>>"+fraction);
    long randomNumber =  fraction + (long)aStart;    
    logger.info("Generated : " + randomNumber);

  }