/usr/share/tomcat7/lib/commons-dbcp.jar is in tomcat7-common 7.0.56-3+deb8u11.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/tomcat7/lib/../../java/commons-dbcp.jar
/usr/share/tomcat7/lib/../../java/commons-dbcp.jar