@Stateful
public class ReentrantStatefulBean {
    @Resource
    private SessionContext ctx;

    private Object state;

    @TransactionAttribute(NEVER)
    public void callMe() {
        this.state = new Date().toString();
        ctx.getBusinessObject(ReentrantStatefulBean.class).check(this.state);
    }

    @TransactionAttribute(REQUIRED)
    public void check(final Object check) {
        if (this.state != check)
            throw new IllegalStateException("EJB 3.1 FR 21.2 I'm not being myself today");
    }
}