Example with a context (The Object-Oriented Thought Process by Matt Weisfeld, 3rd Edition):
Much excitement has been generated over the past several years regarding the portability of code. Much of Java's success was due to the fact that it was highly portable across multiple platforms.The bytecodes produced by Java could be executed on various platforms, as long as the system had a Java virtual machine loaded.The .NET framework provides another, very important, type of portability—portability across various languages.
What do you think is exactly meant by bytecodes in this passage? You see, bytecode is actually an uncountable noun. It is basically the same as other types of programming code in that you can't count it. It is one monolithic mass of statements and control structures.
Although I have seen a similar usage such as a code in another book and took it to mean a program, it still sounds somewhat wrong to me to treat it as a count noun in the context of computer programming. Because the word code when used as a count noun has a clearly defined meaning. It means a system of signs or symbols that's used to send messages. So, a code means something completely different from lines of programming code that you use to write computer programs.