Why java is called as PLATFORM independent? (CoreJava)

Question :Why java is called as PLATFORM independent? (CoreJava)
Answer :Java applications consist of byte-code which may be interpreted by a
virtual engine. Thus, the
applications are able to run on any hardware for which a virtual engine
exists. Interpretation by a
virtual engine means a lower processing speed, compared to compiled
software. To counter this
disadvantage, improvements have been developed, like just-in-time
compilation (JIT), which
translates program instructions of the virtual engine into instructions for
the physical machine.
The result in this case is an aligned program in memory, which can be
executed rapidly without
interpretation. Aditional analysis of the runtime behavior with Hotspottechnology
results in
additional improvements.