Update the DTD reference for Hibernate 3
DTD - Update the DTD reference in your hbm XML files. Change http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd to http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd in the DOCTYPE. If your application took 5 seconds to startup and now takes 50 with Hibernate3, you forgot to change the DTD. Hibernate will then try to lookup (and timeout) the DTD on the Internet for every mapping file instead of its JAR file.