Follows are bug report from Romania.
I think, because is using a deprecated method in JDK 1.7.x.
We have tested the cubrid-manager source (CUBRIDManager-8.4.0.0241-source.tar.gz from http://www.cubrid.org/cubrid_manager) on Ubuntu 11.04 (64 bit) and it does not compile on java 1.7 (results in make_results_java1.7).
We have also tested it on 1.6.0_27 (results in make_results_java1.6) and you can see that the Sun proprietary apis used will be removed in future releases.
The 2 files attached hold the compilation messages when using java 1.6.0_27 and java 1.7. When using java 1.7, 8 errors occur due to the modified version of FtpClient class within java 1.7.