Multi-module projects in Eclipse

Peter Palaga, Red Hat JBoss Portal
DevConf Brno 2015-02-07

Please raise your hand…​

  • Who has ever used (or even tried to use) Eclipse to code in any programming language?
  • Who is/was disappointed with Eclipse?
  • Who is working with large multi-module projects daily, using any IDE?

A multi-module project in Eclipse (1/2)

Take GateIn Portal as a an example:

git clone

... and import to Elipse as a bunch of Maven projects

A multi-module project in Eclipse (2/2)


While the file system hierarchy mirrors the logical structure of the modules


In Eclipse we are presented with a flat list of 109 projects ordered by artifactId








  • Working sets

    • One level only
    • Manual
    • Does not scale when having many modules

  • Naming conventions

    • Name the modules so that they keep the file system order when ordered alphabetically
    • Guaranteed to look stupid in front of IntelliJ and NetBeans users

  • Use multiple workspaces to manage parts of a single source tree?

None of the above helps really

The aim


This is what we want
because this is how we think




Because open source…​

  • Initiative taken by Mickeal Istria and Max Andersen from JBoss Tools team
  • Started in jbosstools-playground repository under the name Nestor
  • Technically simple and elegant, using the available APIs of Project Explorer
  • Demo

User’s perspective

nesting menu
  • Form the user perspective:

    • New context menu in Project Explorer to switch to the hierarchical presentation
    • Backed by a persistent preference

Hierarchical project presentation


Future #defined

Still missing

  • No change in the Package Explorer
  • The same functionality in the Search View

Sum up

  • Things get better in Eclipse

    • Do not leave
    • Eventually come back!

About me

  • My contribution to nested projects was minimal
  • Primarily Senior Sustaining Engineer at Red Hat JBoss Portal
  • Also contributing to several Eclipse plugins ShellEd, FreeMarker Editor, EIRCC