Created attachment 1792595 [details]
engine.log

Description of problem:
Can't create a new instance type, or update an existing one via API with display section specified, see errors:

2021-06-21 07:51:42,824+03 ERROR [org.ovirt.engine.core.bll.CommandsFactory] (default task-70) [4a20edb6-eb5e-4c2c-a014-833f462e1de3] An exception has occurred while trying to create a command object for command 'AddVmTemplate' with parameters 'AddVmTemplateParameters:{commandId='fd72440b-af8b-40a8-bf5e-e61c50e765ae', user='null', commandType='Unknown'}': WELD-000049: Unable to invoke protected final void org.ovirt.engine.core.bll.CommandBase.postConstruct() on org.ovirt.engine.core.bll.AddVmTemplateCommand@6800b0ab
2021-06-21 07:51:42,825+03 ERROR [org.ovirt.engine.core.bll.CommandsFactory] (default task-70) [4a20edb6-eb5e-4c2c-a014-833f462e1de3] Exception: java.lang.NullPointerException
	at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.VmHandler.autoSelectDefaultDisplayType(VmHandler.java:1354)
	at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.VmHandler$Proxy$_$$_WeldClientProxy.autoSelectDefaultDisplayType(Unknown Source)
	at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.AddVmTemplateCommand.init(AddVmTemplateCommand.java:230)
...

2021-06-21 07:53:24,317+03 ERROR [org.ovirt.engine.core.bll.CommandsFactory] (default task-70) [b1c5aab2-796b-4884-b6d3-a63bcb0f60d0] An exception has occurred while trying to create a command object for command 'UpdateVmTemplate' with parameters 'UpdateVmTemplateParameters:{commandId='e40d0ad2-7d53-47e1-9818-e4e74db55e8e', user='null', commandType='Unknown'}': WELD-000049: Unable to invoke protected final void org.ovirt.engine.core.bll.CommandBase.postConstruct() on org.ovirt.engine.core.bll.UpdateVmTemplateCommand@6c4d801d
2021-06-21 07:53:24,317+03 ERROR [org.ovirt.engine.core.bll.CommandsFactory] (default task-70) [b1c5aab2-796b-4884-b6d3-a63bcb0f60d0] Exception: java.lang.NullPointerException
	at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.VmHandler.autoSelectDefaultDisplayType(VmHandler.java:1354)
	at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.VmHandler$Proxy$_$$_WeldClientProxy.autoSelectDefaultDisplayType(Unknown Source)
	at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.UpdateVmTemplateCommand.init(UpdateVmTemplateCommand.java:123)
	at deployment.engine.ear.bll.jar//org.ovirt.engine.core.bll.CommandBase.postConstruct(CommandBase.java:217)
...


Version-Release number of selected component (if applicable):
ovirt-engine-4.4.7.4-0.9.el8ev.noarch

How reproducible:
100%

Steps to Reproduce:
1. Create a new instance type via API with display section specified:
<instance_type>
    <name>create_instance_type</name>
    <display>
        <disconnect_action>NONE</disconnect_action>
        <monitors>1</monitors>
        <smartcard_enabled>true</smartcard_enabled>
        <type>spice</type>
    </display>
</instance_type>

2. Update an instance type via API with display section specified:
<instance_type>
    <display>
        <smartcard_enabled>true</smartcard_enabled>
        <type>vnc</type>
    </display>
</instance_type>


Actual results:
1. Failed to create new instance type via API with display section specified.
2. Failed to update instance type via API with display section specified.

Expected results:
Can create or update instance type via API with display section specified.

Additional info: