java.sql.Date sqlDate = null;
java.util.Date utilDate = new Date();
sqlDate = new java.sql.Date(utilDate.getTime());
PreparedStatement psmtInsert = conn.prepareStatement(insertQuery);
psmtInsert.setDate(1, sqlDate));
psmtInsert.executeUpdate();

PreparedStatement psmtSelect = conn.prepareStatement("select dateOfJoining from EMPLOYEE");
ResultSet resultSet = psmtSelect.executeQuery();
while (resultSet.next()) {
    System.out.println(resultSet.getDate(1));
}

java.sql.Date sqlDate = null;
java.util.Date utilDate = new Date("1397/02/04");
sqlDate = new java.sql.Date(utilDate.getTime());
PreparedStatement psmtInsert = conn.prepareStatement(insertQuery);
psmtInsert.setDate(1, sqlDate));
psmtInsert.executeUpdate();

SELECT TO_DATE(
         '1397/02/05',
         'yyyy/mm/dd',
         'nls_calendar=persian'
       )
FROM   DUAL

| TO_DATE('1397/02/05','YYYY/MM/DD','NLS_CALENDAR=PERSIAN') |
|-----------------------------------------------------------|
|                                      2018-04-25T00:00:00Z |

SELECT TO_CHAR(
         DATE '2018-04-25',
         'yyyy/mm/dd',
         'nls_calendar=persian'
       )
FROM   DUAL

| TO_CHAR(DATE'2018-04-25','YYYY/MM/DD','NLS_CALENDAR=PERSIAN') |
|---------------------------------------------------------------|
|                                                    1397/02/05 |