Free Java FAQS

1. How to get Java in my PC?
   
   First you must get either the J2SE Software Development Kit (SDK) or the J2SE Java Runtime Environment (JRE) in your computer from the Sun download site. If you would just need to run Java applets/applications (or need the plugin for your browser) then you are ok with the JRE (which is only about 10 mb, a quarter of the size of the SDK). Download the SDK (which already includes JRE) if there is a need to compile source files. (If you need to program in Java, then just download the SDK.) As a word of caution, if you can obtain the source files, better leave the binaries (class files) behind and just compile it in your own computer. This would save precious internet bandwidth not to mention saving you from possible risk (ie any binary file is susceptible to virus or it maybe a trojan).
   
   In Linux, the SDK (or perhaps also the JRE) is packaged (two package versions) in a self extracting file. Run that file in the command line, to extract. If you choose the rpm version (get this if your distro uses rpm like Mandrake, Redhat, Fedora), the SDK would be installed in /usr/java (ie there would be a folder /usr/java/j2sdk1.4.2_02/jre). If not, the other version (recommended if you have a non-rpm distro) would extract the j2sdk directory sructure and you should move it to /usr/java.
   
   
2. What version of Java to download?
   
   If you are downloading the JRE just get the latest version. If not, (say you are programming in Java) you have to take into consideration the Java version of your peers or whoever else will be compiling your sources or will use your programs. For example, your teacher is using 1.2 then I do suggest getting that version instead or a lot of bad things may happen (if you can, download also a recent version). Say this or that functions do not exist in your teacher's version. It is interesting to note that Color.BLUE should be Color.blue in earlier versions of Java. If you will be developing, don't jump into the latest version Sun has to offer. Though Sun products are always assured to be of high quality, the market may not be fast to adapt. As of the time I wrote this, 1.5 has just been released but 1.4 is certainly already really stable and robust.
   
   
3. How to set up the Java paths?
   
   Hmmm.. I am a little tempted to say that you should consult the installation instructions of the j2sdk. But that is as bad as saying RTFM. Well, I better be a good man and tell you (I didn't consult those intructions anyway) how I configured my j2sdk.
   
   In win98 you might need to add an entry in the autoexec.bat like this:
       doskey
       set path=c:\progra~1\j2sdk1~1.1_0\bin\
   
   In windows 2000 you need to add a system variable (look this up in the control panel) and make an entry for JAVA_HOME which should have value which is the installation directory of your j2sdk.
   
   In linux, depending on your distro this might differ. After installing j2sdk, try executing java, javac, appletviewer and jar (without giving the absolute path). If it can't be executed, we might be forced to include a soft link (ie a shortcut) to these executables to a system directory like /usr/bin (works in Mandrake and other distro where you can run all executables in /usr/bin without including the path). Read on javaSetup.sh in the scripts folder (included in any Java applet/application download in my gallery) on directions on how this can be done.