code: protected CheckSchemaOperation createCheckSchemaOperation() {
          InputStream in = org.apache.jackrabbit.core.journal.DatabaseJournal.class.getResourceAsStream(databaseType + ".ddl");
          return new CheckSchemaOperation(conHelper, in, schemaObjectPrefix + DEFAULT_JOURNAL_TABLE).addVariableReplacement(
              CheckSchemaOperation.SCHEMA_OBJECT_PREFIX_VARIABLE, schemaObjectPrefix);
      }
docs: This method is called from {@link #init(String, NamespaceResolver)} after the
  {@link #createConnectionHelper(DataSource)} method, and returns a default {@link CheckSchemaOperation}.
  Subclasses can overrride this implementation to get a customized implementation.
  
  @return a new {@link CheckSchemaOperation} instance