Some jar files missing from /jre/lib with package installation on Ubuntu

Some jar files missing from /jre/lib with package installation on Ubuntu.

Installation of jdk-6u18-ea-linux-i586-rpm.bin and jre-6u18-ea-linux-i586-rpm.bin doesn't install all files on Ubuntu x86
rpm is not supported on Ubuntu. ./jdk-6u18-ea-linux-i586-rpm.bin will extract the rpm files but doesn'nt install the bundle.
In order to install the bundle alien is required -

   sudo apt-get install alien (install alien)
   sudo alien jdk-6u18-ea-linux-i586.rpm (convert into deb package)
   sudo dpkg -i jdk_1.6.0_18-1_i386.deb

This will install jdk1.6.0_18 at /usr/java/jdk1.6.0_18
After the installation many jar files are missing under jdk1.6.0_18/jre/lib/ (rt.jar, javaws.jar, plugin.jar).

Cannot check the java -version the error is :
Error occured during initialization of VM
java/lang/NoClassDefFoundError : java/lang/Object

Similarly installation of jdk-6u18-ea-linux-amd64-rpm.bin and jre-6u18-ea-linux-amd64-rpm.bin doesn't install all files on Ubuntu x64.
Cannot check java -version and also jar files missing from /jre/lib location.
Cannot complete installation testing due to missing files
The issue exists for 6u17 also. It happens only on rpm bundles, I mentioned this in the previous description.
Looks like its breaking from the release since the Ubuntu support is there for jdk and there are no install errors. With .sh bundles everything works fine.
I checked for 6u15, 6u16 and 6u17 the issue exists.