Being able to run the very same Java byte code on many different hardware platforms and operating systems was a goal called "write once, run anywhere" from the beginning. This means the Java language and library can't do anything that works on Windows only or Unix only. So you'll find some things missing from Java that are simple in platform-specific languages like VB, or with platform-specific libraries in C.
To make this work, somebody has to implement a JRE on each new hardware platform and operating system. This is a competitive area and Sun is not the only implementor you can choose.
Does that help?
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi