If you are an expirienced Java programmer, you probably want to have the latest JDK on your Debian box. Normally there is no need to install it manually since JDK (as well as JRE) is available in modern distros as .deb package and therefore may be downloaded and installed from one of the official mirrors using familiar apt-get (or aptitude, or Synaptics, or whatever...) interface.
But what if you are not satisfied with the version of Java which is packaged with your distribution? At the moment, the official "production" version of JDK is 6.0 update 3, but for exmaple Debian Etch does not include Java 6 at all (only Java 5 is supported). This is a noticeable drawback since Java 6.0 contains some important features, such as high-quality font antialiasing. The only way to solve this situation is to download the latest JDK from Sun website and install it manually with a bit of Debian magic ;)
So, here are step-by-step installation instructions:
1. Download self-extracting package containing JDK: jdk-6u3-linux-i586.bin.
2. Make sure it has execution privileges:
chmod 755 ./jdk-6u3-linux-i586.bin
3. Run it, answer yes and watch the files being extracted.
4. Copy the extracted directory to /usr/lib/jvm:
sudo cp jdk1.6.0_03 /usr/lib/jvm
5. Check which versions of Java are already installed in your system:
sudo update-alternatives --display java
Notice what priority is assigned to the currently selected one
6. Update symlinks to make them point to your freshly installed Java:
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_03/jre/bin/java 65 --slave /usr/share/man/man1/java.1.gz java.1.gz /usr/lib/jvm/jdk1.6.0_03/man/man1/java.1
7. Check that java has correct version now:
java -version
8. If something went wrong, try assigning higher priority to your JDK or select appropriate version in manual mode:
update-alternatives --config java
9. You can do the same trick with javac:
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.6.0_03/bin/javac 65 --slave /usr/share/man/man1/javac.1.gz javac.1.gz /usr/lib/jvm/jdk1.6.0_03/man/man1/javac.1
