Java programming puzzle

[cgkanchi]

Here's something I ran into while writing some java code. Th question is, why will the following code not run and how would you fix it? I'll post the solution as a hidden post tomorrow. Also, anyone who posts a solution, please post it as hidden.

These are the conditions under which the program is run:
1) The DSN is called test
2) The table is called test
3) The table has a column 'STRING' that has less than a 100 rows
4) The column 'STRING' has some NULL values
5) The column 'STRING' also has some values that are equal to blank Strings (represented as "" by Java
6) *HINT* There are no compile-time errors in the program. If there are, fix them as they are bound to be fairly simple to fix (I haven't tested this code, but it's almost a copy-paste of the same code from a different program.
7) the_JinX is not allowed to participate in the puzzle as he already has the fixed code .
8) If you are copy-pasting this code, in the 12th line remove the space after the first : . I had to put it in there as otherwise AO displays it like this .

import java.sql.*;

class Test 
{
    String stringArray[]=new String[100];
    Connection con;
    Statement stm;
    Resultset rs;

    Test() throws SQLException, ClassNotFoundException
    {
        Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        con=DriverManager.getConnection("jdbc: odbc:test");  //test is the name of the Data Source
       stm=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
        rs=stm.executeQuery("select STRING from test"); //test is the name of a table

        for(int i=0,j=0;rs.next();i++)
        {
             if(rs.getString("STRING")!=null || !rs.getString("STRING").equals(""))
             {
                  stringArray[j]=rs.getString("STRING");
                   j++;
             }
        }
    }
}

Best of luck!!

Cheers,
cgkanchi

[cgkanchi]

Since no one seems to have the solution to this question, here it is:

1) The code

    if(rs.getString("STRING")!=null || !rs.getString("STRING").equals(""))
    {
        stringArray[j]=rs.getString("STRING");
        j++;
    }

will not run for the reason that when rs.getString("STRING")==null, the comparison rs.getString("STRING").equals("") will generate a java.lang.NullPointer exception as parameter being passed to String.equals(String) is a null value and NOT a String.

2) To fix this, the code should read:

    if(rs.getString("STRING")!=null)
    {
         if(!rs.getString("STRING").equals(""))
        {
            stringArray[j]=rs.getString("STRING");
            j++;
        }
    }

Cheers,
cgkanchi