The ObjectMap map cannot be stored in the object_map file.
The object_map file was modified
while the map was loaded into memory. The map cannot be stored if
the object_map file is modified while the map is
loaded into memory. These methods cannot be used to store a map in
this scenario: store(ObjectMap objectMap, java.io.File
file,boolean silent) or public static void store(ObjectMap objectMap,
java.io.File file).
Make sure that the ObjectMap file is not modified
while the ObjectMap map is loaded into memory while trying to store
the ObjectMap map in the ObjectMap file by using the store() method
call of the ObjectMap class.