/usr/lib/jvm/java-1.5.0-gcj-4.6/lib/tools.jar is in gcj-4.6-jre-lib 4.6.3-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/jvm/java-1.5.0-gcj-4.6/lib/../../../../share/java/libgcj-tools-4.6.jar