I have a perfectly working Hibernate application which uses
<hibernate-mapping default-lazy="false" default-cascade="all" ...

Trying to optimize this application I am trying to have one (for now) of my
class mapping file to use default-lazy="true"

However when the app start I get

08:50:19,978 ERROR [main] (FactoryServer.java:FactoryServer:87) - Can not populate DB: javax.persistence.PersistenceException: No Persistence provider for EntityManager named myFactoryPU: Provider named org.hibernate.ejb.HibernatePersistence threw unexpected exception at create EntityManagerFactory:
java.lang.NoSuchMethodError
java.lang.NoSuchMethodError: org.objectweb.asm.ClassWriter.<init>(Z)V
at net.sf.cglib.core.DebuggingClassWriter.<init>(DebuggingClassWriter.java:47)
at net.sf.cglib.core.DefaultGeneratorStrategy.getClassWriter(DefaultGeneratorStrategy.java:30)

googling at other similar problem they are talking about having an
empty parameter constructor which I do have for this class

Could this be related to some of the fields of the class which are also
persistent objects and which have default-lazy="true"

Please advise
thanks