I have an ubuntu 11.10 with eclipse installed, now I am supposed to need JVM, Java compiler and something called API. I am starting to learn Java, because it is easy to make it work on windows after. So what do I install?
The Java Virtual Machine (JVM) is what runs the Java applications (compiled into bytecode). The Java API is the set of existing features that are implemented the runtime libraries: everything documented here. Both the JVM and the runtime libraries form the Java Runtime Environment (JRE). Its main command is
The Java compiler, used via the
The OpenJDK JRE is available in the
Eclipse needs the JRE to run, but provides its own compiler (Eclipse JDT). Strictly speaking, you don't need the JDK to develop with Eclipse, you could compile everything within Eclipse and run your applications through the JRE.
This being said, if you're a beginner, it's certainly worth trying a few toy applications with
Depending on which version of java jre you use, you need to install a
Once you've done that, you should be able to run a
For example A.java:
then compile to A.class
This should output
Then the easiest thing to do is just to install Eclipse, and get started.