@Entity
public class Item {

    @Id
    @GeneratedValue(generator = Constants.ID_GENERATOR)
    public Long id;

    @org.hibernate.annotations.Generated(
        org.hibernate.annotations.GenerationTime.ALWAYS
    )
    public Date lastModified;

    public String name;
}

Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -2
	at java.lang.String.substring(String.java:1875)
	at org.hibernate.persister.entity.AbstractEntityPersister.generateGeneratedValuesSelectString(AbstractEntityPersister.java:1723)
	at org.hibernate.persister.entity.AbstractEntityPersister.generateInsertGeneratedValuesSelectString(AbstractEntityPersister.java:1692)
	at org.hibernate.persister.entity.AbstractEntityPersister.doLateInit(AbstractEntityPersister.java:3989)
	at org.hibernate.persister.entity.AbstractEntityPersister.postInstantiate(AbstractEntityPersister.java:4009)
	at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:479)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1857)
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:843)
	at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:399)
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:842)
	at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:73)
	... 36 more