An IDE-managed application server finished compiling and preparing its artifact, but the server never reached deployment. The decisive message was not a compiler error. It was a debugger listener failure: the configured address could not be bound because it was already in use.

The usual explanation …

An IDE displayed a warning that it could not open a configured application URL. A browser opened the same route successfully soon afterward, and the application was already answering real requests. The warning looked like an application failure, yet the user-visible route was healthy.

The useful …

A local WMS instance had a JDBC configuration that clearly targeted a test database, yet its users, permissions, and parts of its UI behaved as if they came from another environment. Looking at one configuration file made it tempting to conclude that the application had silently switched databases. …