Portability is a consequence of good design and the architecture-neutral approach. Every machine has its own unique byte code interpreter, since that must be coded for each platform. However, they all accept the same byte code. There are standards for the suitable values of the simple types. For example, an int must be a 32 bit 2's complement binary integer on all machines, regardless of how the local machine implements integers. The Java compiler is itself written in Java, as are most of the other tools, so they are exactly the same for all platforms. Thus, Java is portable.
b) or back to Java is Architecturally Neutral
n) or next to Java is High-Performance
or
x) or out to Sun's Definition of Java