Hi,
                    
                    
                    
                    I have a repeatable failure with Photon / m2e /
                      wtp projects. I'm not sure it is related with m2e,
                      but as I think it is highly related with the way
                      project's build path is configured, your insight
                      may be important. Also I found no report about
                      this issue, so I think it is not an issue for
                      vanilla Eclipse project.
                    
                    
                    
                    TLDR; Inspect and Debug shell is impossible in
                      dependencies in a WTP Tomcat Server with Photon
                      (Unable to evaluate the selected _expression_). It
                      used to work with Oxygen. I find a workaround, but
                      this bug is really annoying. Only Debug Server is
                      buggy ; a Debug as... Junit test works fine.
                    
                    
                    
                    This bug can be reproduced following this steps
                      :
                    
                    * download jee package for eclipse photon
                      (buildid 20180619-1200, eclipse m2e
                      1.9.0.20180606-2036, eclipse m2e wtp
                      1.4.0.20180606-2005)
                    
                    
                    * with Git Perspective, add the git repository
                      and import the selected project. Maven nature is
                      detected automatically
                    
                    * create a Tomcat 9.0 Server and add the test
                      webapp
                    
                    * Debug Tomcat server
                    
                    * put a breakpoint on TestServlet.doGet
                    
                    
                    * step in StringUtils.isAllBlank(...)
                    
                    * perform an inspect or debug-shell on
                      "ArrayUtils.isEmpty(css)"
                    
                    * it fails with "Unable to evaluate the
                      selected _expression_"
                    
                    
                    
                    A known workaround for this is :
                    
                    * click on the stacktrace in debug view
                    
                    * right-click -> Edit source lookup
                    
                    * tick Search for duplicate source -> apply
                    
                    * choose StringUtils.class in the list (opposed
                      to org/apache/commons/...)
                    
                    * inspect/debug-shell is working again ; but
                      this process must be done for all class you want
                      to debug
                    
                    
                    
                    Do you reproduce this issue ? Do you think it
                      is m2e related (the way maven project is
                      configured) or wtp related ? How can I help to fix
                      this issue ?
                    
                    
                    
                    Thanks,
                    
                    
                    
                    Laurent Almeras