Bug 296800 [GlobalActions] UI build actions should not lock the workspace
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/actions/BuildAction.java
* Returns the projects to build.
     * This contains the set of projects which have builders, across all selected resources.
     */
    List getProjectsToBuild() {
        if (projectsToBuild == null) {
            projectsToBuild = new ArrayList(3);
            for (Iterator i = getSelectedResources().iterator(); i.hasNext();) {
                IResource resource = (IResource) i.next();
                IProject project = resource.getProject();
                if (project != null) {
                    if (!projectsToBuild.contains(project)) {
                        if (hasBuilder(project)) {
                            projectsToBuild.add(project);
                        }
                    }
                }
            }
        }
        return projectsToBuild;
    }
    /**
     * Returns whether there are builders configured on the given project.
     *
     * @return <code>true</code> if it has builders,
     *   <code>false</code> if not, or if this couldn't be determined
     */
    boolean hasBuilder(IProject project) {
    	if (!project.isAccessible())
    		return false;
        try {