When building Hibernate Tools with JDK 1.7 there are a number of tests in error with a similar message:

testCompilable(org.hibernate.tool.hbm2x.Hbm2EJBDaoTest) Time elapsed: 0.092 sec <<< ERROR!
java.lang.RuntimeException: ----------
1. ERROR in /Users/koen/Workspace/Hibernate/hibernate-tools/toolstestoutput/hbm2daooutput/comparator/NoopComparator.java
(at line 1)
package comparator;
^
The type java.lang.Object cannot be resolved. It is indirectly referenced from required .class files
----------
1 problem (1 error)
at org.hibernate.tool.test.TestHelper.compile(TestHelper.java:110)
at org.hibernate.tool.hbm2x.Hbm2EJBDaoTest.testCompilable(Hbm2EJBDaoTest.java:53)

The problem can be solved by using a more recent version of org.eclipse.jdt.core.