ClassCastException on Entity update

You might want to doublecheck the logic in
org.apache.olingo.odata2.processor.core.jpa.access.data.JPAEntity:write(final Map<String, Object> oDataEntryProperties, final boolean isCreate)

On line 141 there's an explicit cast to List<ODataEntry>. However I found out that during update, when the property is a 1:1..0 relation to another Entity, the returned type is ODataEntry. And that causes the ClassCastException.

I managed to solve this for me with a simple if/else block:

List<ODataEntry> relatedEntries = null;
if(oDataEntryProperties.get(propertyName) instanceof ODataEntry){
relatedEntries = new ArrayList<ODataEntry>();
relatedEntries.add((ODataEntry)oDataEntryProperties.get(propertyName));
} else {
relatedEntries = (List<ODataEntry>)oDataEntryProperties.get(propertyName);
}

The code is from the 1.1.0-SNAPSHOT master branch HEAD.
I hope that helps.