Once you install the jdk, there are a few things to do. These instructions are for windows. On Mac it will be very similar except that you can skip step1.


1)Find the location of javac on your machine. For me, it was installed in
C:\ProgramFiles\Java\jdk1.6.0_23\bin\javac

2)Once you have found that. Go to start--->run and type cmd. (In Mac OsX, look for the program "Terminal")

3)Find the *full* path of the HelloWorld.java file that you created. (For
the example, assume you put everything into
C:\Documents\comp202stuff\HelloWorld.java 

4)Type

cd C:\Documents\comp202stuff

(cd stands for change directory. Basically what you want is for the cursor
to flash in front of the entire path of your folder. The command on mac is still cd, but the path will look a bit different. It will most likely look like /Users/Dan/Documents/comp202stuff)

5)Type "C:\Program Files\Java\jdk1.6.0_23\bin\javac" HelloWorld.java

You will have to put the "C:\Program Files\Java\jdk1.6.0_23" in " "
because of spaces. As you are typing, you can press tab many times in a
row and it will cycle through possible directories in the folder. (On mac you can just type javac)

This should create the file HelloWorld.class

Note that if things work successfully, there will not be any information output. It will create the .class file in the same folder as the .java file without outputing a message.

6)Type "C:\Program Files\Java\jdk1.6.0_23\bin\java" HelloWorld

to run it.

http://www.skylit.com/javamethods/faqs/javaindos.html

may be a useful link too....



By the way, if you are using Windows and want to avoid typing the entire C:\Program
Files\Java\jdk1.6.0_23\bin every time, you can edit the list of folders
that windows automatically scans when you type a command.

To do this in windows7, follow these instructions:
http://www.itechtalk.com/thread3595.html

It should be mostly the same in windows xp or vista.