java.lang.NullPointerException
at org.jboss.tools.hibernate.jpt.core.internal.context.java.JavaDiscriminatorFormulaImpl.setValue(JavaDiscriminatorFormulaImpl.java:55)
at org.jboss.tools.hibernate.jpt.ui.internal.mapping.details.HibernateDiscriminatorColumnComposite$3.setValue(HibernateDiscriminatorColumnComposite.java:206)
at org.jboss.tools.hibernate.jpt.ui.internal.mapping.details.HibernateDiscriminatorColumnComposite$3.setValue(HibernateDiscriminatorColumnComposite.java:1)
at org.eclipse.jpt.common.ui.internal.utility.swt.TextFieldModelBinding.setTextModelText(TextFieldModelBinding.java:176)