Debugging JSPs with Maven Jetty plugin gives "Warning: Breakpoint does not belong to any class"

I've been tasked with improving a legacy system which uses Maven for building, and the Maven Jetty Plugin to run Jetty during development. The project in itself consists of one mother pom, and two child poms: a "jar" and a "web" module, respectively.

Since this a legacy system that's been developed for over a decade, the JSPs have large amounts of business logic in them (often utilizing classes from the jar-module which are injected through Spring), and I've now reached a point where I feel I cannot live anymore without having a debugger for the JSPs. However, every breakpoint I place in a JSP becomes a red circle with a cross in it which states "Warning: Breakpoint does not belong to any class", and, consequently, the debugger does not heed it.

I've tried to set MAVEN_OPTS to run the debugger, and then attaching to it from a simple "Remote" Run/Debug Configuration, but it still ignores the breakpoints in JSPs. Breakpoints in Java files works fine, though.


Anyone have any ideas what may be causing this?