I can confirm this issue with version 5.2.8-Final of hibernate.
I came across this issue while upgrading hibernate from 4.3.7 to 5.2.8.
The breaking change is located at InformationExtractorJdbcDatabaseMetaDataImpl#getTables Line 320. Here the schemaFilter is set to an empty string. In version 4.3.7 the schemaFilter was set to null.

The ojdbc6 driver from Oracle appends the empty string as namespace and therefore does not find any tables. See here OracleDatabaseMetaData#getTables Line 914