Prepared statments error

Question

i have this error for my preparedstatments
exception in dbMember.createPreparedStatements() : String index out of range : 0
what does it means?
i am trying to call my selectMemMaxID function to retrieve the max id from my member table
this is my selectMemMaxID method
public void selectMemMaxId() throws Exception
          try{
               ResultSet rs = selectMaxIdPstmtMem.executeQuery();
               setMemMaxId(rs.getInt(1));
               catch (SQLException e)
                    System.out.println("SQLException thrown" + e.getMessage());
and this is my createPreparedStatments() method
     public void createPreparedStatements()
          try
//For select Max Id in memberparticular table
               selectMaxIdStrMem = "select max(memparticular_memid) as MaxId from memberparticular";
               selectMaxIdPstmtMem = dbConn.createPreparedStatement(selectMaxIdStrMem);
          catch (Exception e)
System.out.println("Exception in dbMember.createPreparedStatements() : " + e.getMessage() );

Answer 1

i did try doing that
public void selectMemMaxId() throws Exception
          try{
               ResultSet rs = selectMaxIdPstmtMem.executeQuery();
          while (rs.next())
               setMemMaxId(rs.getInt(1));
               catch (SQLException e)
                    System.out.println("SQLException thrown" + e.getMessage());
but it still return me a java.lang.NullPointerException error and
the error i stated above