Question

I’m getting a weird behavior while doing a search query in a @Lob field.

I’m using HSQLDB and Hibernate with JPA2.

The query is: @NamedQuery(name = "URL.findByPathAndDomain", query = "select u from URL u where u.path = :path and u.domain.domain = :domain") (path is the @lob field, by the way).

And I implemented the method in DAO like this:

public URL findByPathAndDomain(String path, String domain) {
        URL url = null;
        TypedQuery<URL> query = em().createNamedQuery("URL.findByPathAndDomain", URL.class);
        query.setParameter("path", path);
        query.setParameter("domain", domain);
        try {
            url = query.getSingleResult();
        } catch (NoResultException e) {
            logger.error(e.getMessage());
        }
        return url;
    }

And I’m getting this exception:

Caused by: org.hibernate.exception.GenericJDBCException: java.lang.NullPointerException java.lang.NullPointerException
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:129)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81)
    at $Proxy45.executeQuery(Unknown Source)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1897)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1698)
    at org.hibernate.loader.Loader.doQuery(Loader.java:832)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:293)
    at org.hibernate.loader.Loader.doList(Loader.java:2382)
    at org.hibernate.loader.Loader.doList(Loader.java:2368)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2198)
    at org.hibernate.loader.Loader.list(Loader.java:2193)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:470)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:355)
    at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:195)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1248)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101)
    at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:285)
    ... 10 more

If I remove the @Lob annotation, everything goes fine.
Is it a HSQLDB bug, a Hibernate bug, or what?

EDIT: I change the PU to use MySQL instead of HSQLDB, and it works like a boss…

Answer 1

The NPE occurs within Hibernate’s StandardSQLExceptionConverter. Similar NPE was found and reported last year. I recall in some cases, when convertion was not possible by the database, the reporting of the error by Hibernate was broken and resulted in the NPE.

Best course of action is to use a large VARCHAR field instead of LOB.