New to Java

I need to compare a byte to a null value for a program I am writing, in order to catch these values to stop them being printed in an output file as "<nul>".

At first, I tried

      for (int i=1; i<=127; i++)
	if (AwaitData.received[i] == null)

but this gives the error:
StoreData.java:14: incomparable types: byte and <nulltype>

I then tried the idea of making a Byte and setting its value to null:

 Byte NULL = null; 

But this doesn't work either, giving a null pointer exception when I run the for loop:
Exception in thread "main" java.lang.NullPointerException
at StoreData.doIt(StoreData.java:14)

Is there any way of actually doing this?
Thanks.