Every new version of an OS is subject to generating secondary effects and the latest Ubuntu version has an impact on BT747.
By default OpenJDK Java 6 is installed for the core java virtual machine and libraries and Icedtea to enable 'Java Web Start'.
Unfortunately that seems to result in some trouble here and there so I recommend to install the 'sun-java6' package instead. Sun has been acquired by Oracle, but the package still is 'sun-java6'.