Use unwrap instead of cast to get implementation specific interface in EclipseLink Oracle Extension

[peterzberg]

Describe the bug
In a container environment, connections, statements, .. may be wrapped. So casting to the expected class will fail.

Example: https://github.com/eclipse-ee4j/eclipselink/blob/4.0.2/foundation/org.eclipse.persistence.oracle/src/main/java/org/eclipse/persistence/platform/database/oracle/Oracle9Platform.java#L178

In Openliberty, this PreparedStatement is a com.ibm.ws.rsadapter.jdbc.v43.WSJdbc43PreparedStatement that wrapps the OraclePreparedStatement which leads to "java.lang.ClassCastException: class com.ibm.ws.rsadapter.jdbc.v43.WSJdbc43PreparedStatement cannot be cast to class oracle.jdbc.OraclePreparedStatement "

To Reproduce
Steps/resources to reproduce the behavior:

• EclipseLink version: 4.0.2
• Java/JDK version: x
• Entity source (mainly applied annotations)

@TypeConverters({
  @TypeConverter(name = "nvarcharConvProperty", dataType=org.eclipse.persistence.platform.database.oracle.NString.class, objectType=String.class)
})

1. For problem in persistence (JPA)
   • JPA context like persistence.xml settings or related system properties (in case of JPA): Nothing special
   • Database provider/version: com.oracle.database.jdbc:ojdbc11:23.2.0.0
   • JDBC driver provider/version (it should be useful if bug is related with some "specific" datatype e.g. JSON): com.oracle.database.jdbc:ojdbc11:23.2.0.0

Expected behavior
Statements gets unwrapped and no ClassCastException will be thrown.

Additional context
The problem occured within Openliberty 23.0.0.12. I can try to create an example to reproduce this behaviour. I can try to create an example if needed.

[peterzberg]

OraclePreparedStatement oraclePreparedStatement = statement.unwrap(OraclePreparedStatement.class);
oraclePreparedStatement.setFormOfUse(index, oracle.jdbc.OraclePreparedStatement.FORM_NCHAR);