code: private static PersistenceUnit newPersistenceUnit(final String fJndiName, final String fUnitName)
      {
          return new PersistenceUnit()
          {
              @Override
              public String name()
              {
                  return fJndiName;
              }
  
              @Override
              public Class<? extends Annotation> annotationType()
              {
                  return javax.persistence.PersistenceUnit.class;
              }
  
              @Override
              public String unitName()
              {
                  return fUnitName;
              }
  
              @Override
              public String toString()
              {
                  return "JPA.PersistenceUnit(name=" + fJndiName +
                         ", unitName=" + fUnitName + ")";
              }
          };
      }
docs: This transient PersistencUnit annotation class has no default value.
  i.e. null is a valid value for some fields.