what could be the reason behind this exception?

[jyotsana dang]

here is my jsp code for browsing the records that have been inserted:
<%
Connection con=null;
java.sql.Statement stmt=null;
ResultSet rs=null;
boolean y=false;
int i;
String xy=(String)session.getAttribute("y");
%>

<table border="1" cellpadding="1" cellspacing="1">
<th>
<% out.print("Level"); %>
</th>

<th>
<% out.print("Project Title"); %>
</th>

<th>
<% out.print("Student Names");%>
</th>

<th>
<% out.print("Co-Supervisor"); %>
</th>

<th>
<% out.print("Year"); %>
</th>
<%
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
con=DriverManager.getConnection("jdbc dbc:mech_iit");
stmt=con.createStatement();
int count=0;
rs=stmt.executeQuery("select top 4* from projects_supervised where user_login='"+xy+"' order by project_id");
while(rs.next()) {
count++;


%>

<tr>
<td><% out.print(rs.getString(2)); %>
</td>
<td><% out.print(rs.getObject(3).toString()); %>
</td>
<td><% out.print(rs.getObject(4).toString()); %>
</td>
<td><% out.print(rs.getObject(5).toString()); %>
</td>
<td>
<% out.print(rs.getObject(6).toString()); %>
</td>
</tr>
<%

}
if(count==0)
{
{
out.println("<p><b>No records found</b></p>");
}
}
}
catch(Exception e)
{
System.out.println("exception in block"+e);
}
rs.close();
stmt.close();
%>
</table>
This jsp page throws a null pointer exception. But in fact when i use the same code for seeing other inserted records from a different table then the page works fine.

[Prakash Dwivedi]

Can you provide us more information like, stacktrace

[Nicholas Cheung]

The only case I think of the NullPointerException is that, when you execute the statement, exception thrown. Since you catch it, and thus the code continues to execute. But then, as the code: stmt.executeQuery(...) throws exception, rs may still be null.
Then, when you call rs.close(), this causes the NullPointerException.
But of course, we need to trace the error to confirm the problem.
Nick.

[David Peterson]

Or perhaps more likely, since you say it works OK on a different table, one of the records in the "projects_supervised" table contains a NULL value for one of the fields (e.g. project title), and so rs.getObject() returns null. You can't call toString() on a null.

[Praful Thakare]

Hi,
I guess you can try without toString()...if it prints address insted of value then try out.println(rs.getObject()+"");
and wondering why you are not using rs.getString() instead of getObject.
Cheers
Praful