How to uninstall classpath-gtkpeer from Ubuntu
To uninstall just classpath-gtkpeer package itself from Ubuntu execute on terminal:
sudo apt-get remove classpath-gtkpeer
Uninstall classpath-gtkpeer and it's dependent packages
To uninstall the classpath-gtkpeer package and any other dependant package which are no longer needed on Ubuntu.
sudo apt-get autoremove classpath-gtkpeer
If you also want to delete configuration and/or data files of classpath-gtkpeer from Ubuntu then this will work:
sudo apt-get purge classpath-gtkpeer
To delete configuration and/or data files of classpath-gtkpeer and it's dependencies from Ubuntu then execute:
sudo apt-get autoremove --purge classpath-gtkpeer
classpath-gtkpeer package information
clean room standard Java libraries - GTK+ AWT peer
GNU classpath provides a free replacement for Sun's proprietary class libraries so that the GNU system can run programs written in the Java language. GNU Classpath makes it possible to compile DFSG-free programs written in the Java language without depending on proprietary class libraries. GNU Classpath can be used to run Java applications without depending on proprietary software. This package contains the GTK+ AWT peer to run GUI applications.
More information about apt-get remove
Advanced Package Tool, or APT, is a free software user interface that works with core libraries to handle the installation and removal of software on Debian, Ubuntu and other Linux distributions. APT simplifies the process of managing software on Unix-like computer systems by automating the retrieval, configuration and installation of software packages, either from precompiled files or by compiling source code.
apt-get is the command-line tool for handling packages, and may be considered the user's "back-end" to other tools using the APT library.
apt-get remove is identical to install except that packages are removed instead of installed. Note that removing a package leaves its configuration files on the system. If a plus sign is appended to the package name (with no intervening space), the identified package will be installed instead of removed.