java - Javaでストアドプロシージャを呼び出せません

Question

stored procedureで書きPostgreSQLます。Javaでこの手順を使用しようとすると、「org.postgresql.util.PSQLException: ERROR: cursor " < unnamed portal 1 > " does not exist」例外がスローされます。

手順：

CREATE OR REPLACE FUNCTION subject_show(session_id CHARACTER VARYING,OUT result_cursor refcursor, OUT total_record INTEGER, OUT total_search_record INTEGER  ) AS $$
        BEGIN
            total_record:=23;
            total_search_record:=22;
            OPEN result_cursor FOR SELECT "ID","NAME"   FROM "SUBJECTS" ;
    END;
    $$ LANGUAGE plpgsql;

プロシージャの呼び出しjava:

...

callableStatement = conn.prepareCall("{ call subject_show(?,?,?,?) }");
callableStatement.setString(1, sessionID);
callableStatement.registerOutParameter(2, Types.REF);
callableStatement.registerOutParameter(3, Types.INTEGER);
callableStatement.registerOutParameter(4, Types.INTEGER);
callableStatement.executeUpdate();
System.out.println(callableStatement.getObject(3));
System.out.println(callableStatement.getObject(4));
rs = (ResultSet) callableStatement.getObject(2);
...