Step to reproduce :

• remove an element from the config.xml file
• click the restart in safe-mode button

After the page reload, the following error appears :

{{java.lang.NullPointerException: Cannot invoke "org.ametys.runtime.config.Config.getValue(String)" because the return value of "org.ametys.runtime.config.Config.getInstance()" is null
at org.ametys.plugins.repository.maintenance.MaintenanceTaskClientSideElement.isJndi(MaintenanceTaskClientSideElement.java:52)
at org.ametys.workspaces.repository.maintenance.ui.MaintenanceTaskClientSideElement.getUnavailableDescription(MaintenanceTaskClientSideElement.java:76)
at org.ametys.plugins.repository.maintenance.MaintenanceTaskClientSideElement.getUnavailableDescription(MaintenanceTaskClientSideElement.java:44)
at org.ametys.workspaces.repository.maintenance.ui.MaintenanceTaskClientSideElement.getScripts(MaintenanceTaskClientSideElement.java:57)
at org.ametys.core.ui.StaticFileImportsClientSideElement.getScripts(StaticFileImportsClientSideElement.java:263)
at org.ametys.core.ui.RibbonConfigurationManager._resolveReferences(RibbonConfigurationManager.java:1153)
at org.ametys.core.ui.RibbonConfigurationManager._createGroupForUser(RibbonConfigurationManager.java:1103)
at org.ametys.core.ui.RibbonConfigurationManager._generateTabGroups(RibbonConfigurationManager.java:895)
at org.ametys.core.ui.RibbonConfigurationManager.saxRibbonDefinition(RibbonConfigurationManager.java:815)
at org.ametys.plugins.core.ui.WorkspaceGenerator.doGenerate(WorkspaceGenerator.java:162)}}

This is due to the fact that the application is in a "Forced safe mode" state instead of a "no config" state. When in "no config" a specific workspace is loaded with only a few element that don't require the config. But in a "safe mode" state, the config is assumed to be valid and some safe component try to read it