hbm2ddl tools SchemaUpdate and SchemaExport provides interface to generate update/create script. Now it is not support output to script file not modifying the database.
Example: SchemaUpdate.execute(true, false) throws SchemaManagementException: BIG PROBLEM
The implemetation in Hibernate 4 receives list of update scripts from Configuration }}({{Configuration.generateSchemaUpdateScriptList) and then apply them to output. New implemetation in Hibernate 5 uses SchemaMigrator, which firmly connected to the database.