[WICKET-6451] Components with collection models do not support unmodifiable or empty sets

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 8.0.0-M6
• Fix Version/s: 8.0.0-M8
• Component/s: wicket
• Assignee: Sven Meier
• Reporter: Kamil
• Created: 14/Aug/17 16:00
• Updated: 31/Aug/17 11:09
• Resolved: 31/Aug/17 09:36

Description

When object returns Collections.unmodifiableSet() it is obvious that model object can not be updated.
But the exception that was thrown causes me to spend hours until I found out that:

Last cause: Could not convert value: [] to type: java.util.Set. Could not find compatible converter.
WicketMessage: An error occurred while trying to set the collection attached to [BootstrapMultiSelect [Component id = children]]

Is not about converter but about unmodifialble set, because the real exception was hidden!

1)Run the app
2)Click submit
3)Caused by User#L30

Issue Links

• is duplicated by: WICKET-6450 FormComponent should not always create ArrayList when field is null