The difference between Byte and Stream - what do you mean? Those two are two totally different things. It's like asking "What's the difference between a cup of coffee
and a bicycle?".
Can you explain why you are asking this quesion, in what way are you not clear about the difference between Byte and Stream?
Byte is a wrapper class for the primitive type byte (see the API documentation of java.lang.Byte). There's no class or interface called Stream in the standard Java API. There are InputStream and OutputStream, in the package java.io. Streams are 'channels' to transport data from one place to another, for example from a file on disk to memory or vice versa.