how to install "jdk-1_5_0_22-linux-amd64-rpm.bin"

You have probably download the wrong file. The RPM doen't work on ubuntu.

If you use a 32bit system, download it here:
http://javadl.sun.com/webapps/download/AutoDL?BundleId=49015

If you use a 64bit system, download it here:
http://javadl.sun.com/webapps/download/AutoDL?BundleId=49019

Then, follow the istruction reported here:
http://www.java.com/en/download/help/linux_x64_install.xml#install

Or follow this if you have a 32bit system:
http://www.java.com/en/download/help/linux_install.xml#selfextracting

http://compixels.com/6805/how-to-install-java-in-ubuntu-11-04-natty-narwhal-via-ppa

I recommend using actionparsnip's way (or installing from the Canonical partner repository, though the PPA may provide more current versions). The benefits are that (a) the packages you are installing are designed and intended for Ubuntu, (b) software that relies on Java will know that it is installed and how to use it, and (c) Java will be updated when you update the rest of your system.

Of course, you might prefer to use the free open source software version of Java (openjdk and icedtea), which is also official. See https://help.ubuntu.com/community/Java for details about your various options.