Molindo Techblog

I got this Error today after changing the primary key of my model objects from int to Serializable (as I wanted all of my objects, even the ones with a String primary key to use the same API, which was limited to int). But when I started the app I got the Error and the following Exception:

org.hibernate.type.SerializationException: could not deserialize
at org.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:217)
at org.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:240)
at org.hibernate.type.SerializableType.fromBytes(SerializableType.java:82)
at org.hibernate.type.SerializableType.get(SerializableType.java:39)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:163)
at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:154)
…..

I even got this one as cause:

Caused by: java.io.EOFException
at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2279)
at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2748)
at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:780)
at java.io.ObjectInputStream.(ObjectInputStream.java:280)
….

EOF? wtf? Don’t get too confused with that EOF, the solution was simply to add the type of the id in the mapping file.

Before:

<id name=”id”>
<generator class=”native”>
</id>

After:

<id name=”id” type=”integer”> <!– or long or string of whatever your hibernate type is –>
<generator class=”native”>
</id>