title: What is the meaning of "Java is portable"?
body: <p>I'm confused about Java portability. If the Java language is portable, why is <code>enum</code> unknown in J2ME?</p>
  <p>In C++, it's not important which platform or library is used. The &quot;C++ language&quot; doesn't change in all platforms.</p>
  <p>My purpose is developing a Java library that just uses primitive types like <code>int</code>, <code>String</code>, or <code>Array</code> (something like a library for <code>Genetic algorithms</code>). I want to use this library in mobile and desktop applications. But it seems that <code>enum</code> and some other keywords do not exist in all platforms.</p>
  <p>So I think I misunderstood the meaning of &quot;Java portability&quot;. What does that mean?</p>