Chapter 5. Apple Extensions
Apple ships a nonstandard
JVM with proprietary extensions.
There桰've said it, and the cat is out of the
bag. So why isn't Apple lumped into the same
category as other vendors that ship proprietary JVMs? Why has Apple
not been accused of trying to co-opt Java for sinister purposes? Put
simply, Apple's JVM extensions are just
that梕xtensions. They don't change what Java
is, but add additional functionality on top of and around a normal
Java environment. Apple ships a complete implementation of not just
the
Java Runtime
Environment (JRE), but a full Java Development Kit (JDK). The
extensions just include some icing on the standard Java cake.
Apple's Java implementation is fully compliant with
any Java 2/JDK 1.3/4-based "pure"
Java application. Certain vendors ship incomplete JVM implementations
for strategically competitive reasons, in opposition to technologies
such as RMI and CORBA. Apple's extensions to Java,
however, principally address weaknesses in the Java platform. Careful
application development lets you support these extensions while still
maintaining excellent cross-platform compatibility. This chapter
explores these extensions and shows how they can add to standard Java
programs (like the editor from the last chapter).
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When comparing
Apple's extensions to the efforts of other vendors
(Microsoft in particular), keep the following in mind:
Apple's extensions are (to the developer) just
classes that allow you to more easily access Mac OS X functionality. The extensions do not add to the language model itself (e.g.,
additional keywords). The full Java 2 Standard Edition stack is included. Apple's JVM is compliant with all relevant Java
specifications.
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