As Jamie points out, we should use pe as the cause, rather than writing them

out of the (chain of exception) inheritance.

src/main/java/com/samskivert/depot/PersistenceContext.java

@@ -556,7 +556,7 @@ public class PersistenceContext
             conn = _conprov.getConnection(_ident, isReadOnly);
         } catch (PersistenceException pe) {
             throw new DatabaseException("Failed get connection [ident=" + _ident +
-                                        ", isRO=" + isReadOnly + "]", pe.getCause());
+                                        ", isRO=" + isReadOnly + "]", pe);
         }
 
         // wrap the connection in a proxy that will collect all opened statements