InternalException & UserException using objectdb with Jboss AS 7.1.1 final

Hello.

We are currently using ObjectDB in application server Jboss as 7.1.1.final. ObjectDB version is 2.5.3_02.
The following errors occur when multiple ajax requests are executed:

Caused by: com.objectdb.o.InternalException: Error reading UTF string

Caused by: com.objectdb.o.UserException: Mismatch client-server protocol prefix

Our current settings:

Persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
 
    <persistence-unit name="DP_PU" transaction-type="JTA">
        <provider>com.objectdb.jpa.Provider</provider>
        <properties>
            <property name="jboss.as.jpa.providerModule" value="com.objectdb" />
            <property name="javax.jdo.option.MaxPool" value="50"/>
            <property name="javax.persistence.jdbc.url" value="objectdb://localhost:6136/dp.odb"/>
            <property name="javax.persistence.jdbc.user" value="admin"/>
            <property name="javax.persistence.jdbc.password" value="admin"/>
        </properties>
    </persistence-unit>

    <persistence-unit name="SESSION_PU" transaction-type="JTA">
        <provider>com.objectdb.jpa.Provider</provider>
        <properties>
            <property name="jboss.as.jpa.providerModule" value="com.objectdb" />
            <property name="javax.jdo.option.MaxPool" value="50"/>
            <property name="javax.persistence.jdbc.url" value="objectdb://localhost:6136/dp_sessions.odb"/>
            <property name="javax.persistence.jdbc.user" value="admin"/>
            <property name="javax.persistence.jdbc.password" value="admin"/>
        </properties>
    </persistence-unit>
              
</persistence>

The module is described as:

<?xml version="1.0" encoding="UTF-8"?>

<module xmlns="urn:jboss:module:1.0" name="com.objectdb">
    <resources>
        <resource-root path="objectdb-jee.jar"/>
    </resources>
    <dependencies>
        <module name="javax.api"/>
        <module name="javax.persistence.api"/>
        <module name="javax.transaction.api"/>
        <module name="javax.validation.api"/>
     </dependencies>
</module>

However, when ObjectDB operates in integrated regime (the connection line is the absolute path to the database)

<property name="javax.persistence.jdbc.url" value="objectdb:/usr/share/objectdb/db/dp.odb"/>

no such errors occur.

Could you please specify possible reasons of the errors described.
Full description of exception logs is attached.

Thank you in advance

More information is needed.

Possibly this is related to registering persistable types in the database concurrently, i.e. when running the application with a new empty database or after applying schema change.

If you get this exceptions only with a new database, can you check your application with a database in which all the entity types have already been registered?