Target Definition
Target definition can be added by
Windows > Preferences > Plug-in Development > Target Platform menu.
: Reload command is useful when you copied some bundle to plugin folder newly.
: In the case of locations, variables can be used as below
ex) ${project_loc}\lib
ex) ${eclipse_home}
If you specify import packages in the MANIFEST.MF file as below,
Import-Package:
javax.servlet.jsp.jstl.fmt
If no problem is, the specified jar will be added to the Plug-in Dependencies.
If not, check if the jar file including that package is in the target definition folder. This validation can be run at the "Run configuration" dialog as well.