NullPointerException - why?

Question

I am getting a Null Pointer Exception. And i have used the long text data type in the ms access table to for date and description

 try
         {
         int z1=1,z2=2;
             String s=JOptionPane.showInputDialog("enter the date(DD/MM/YEAR)");
         String s1=JOptionPane.showInputDialog("enter data into your dairy");
         pstmt=conn.prepareStatement(" INSERT  INTO  Table2(date,description) values(?,?)");
         pstmt.setString(z1, s);
         pstmt.setString(z2, s1);
         pstmt.executeUpdate();
         JOptionPane.showMessageDialog(null, "Data enterd successfully");
         update1();
         close();
         }

         catch(Exception e1)
         {
             JOptionPane.showMessageDialog(null, "Data Insertion failed.This date may already exist or may be some other error");
             JOptionPane.showMessageDialog(null, "ERROR:"+e1.getMessage());

         }

I have used data type long text for date and description in the ms access table.

please post error stack trace and code part where you open a connection... — user4341206, Apr 14 '15 at 12:14
Print full stack trace... Do s and s1 have values or are they null (try hardcode s and s1 and check if you still get same error)? — user4341206, Apr 14 '15 at 12:16
conn = DriverManager.getConnection("Jdbc:Odbc:des","",""); stmt=(Statement) conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY); — Karrthik Reddy Chinasani, Apr 14 '15 at 12:17
The `null` variable is probably `pstmt` or `conn` the other ones can't be `null` — Titus, Apr 14 '15 at 12:21
catch(Exception e1) { JOptionPane.showMessageDialog(null, "Data Insertion failed.This date may already exist or may be some other error"); JOptionPane.showMessageDialog(null, "ERROR:"+e1.getMessage()); } — Karrthik Reddy Chinasani, Apr 14 '15 at 12:32
Pls don't post code/stacktrace as comment but edit your original post (OP). — flo, Apr 14 '15 at 12:40

score 0 · Answer 1 · answered Apr 14 '15 at 12:44

Replace your code by

int z1=1,z2=2;  
String s="14/04/2015";  
String s1="test";  
if ( conn != null ) {
    pstmt=conn.prepareStatement(" INSERT  INTO  Table2(date,description) values(?,?)");
    if ( pstmt != null ) {
        pstmt.setString(z1, s);
        pstmt.setString(z2, s1);
        pstmt.executeUpdate();
    }
    else {
        System.out.printl("pstmt is null!");
    }
}
else {
    System.out.printl("conn is null!");
}

And copy the output here.

the output is conn is null. – Karrthik Reddy Chinasani Apr 14 '15 at 12:52 — Karrthik Reddy Chinasani, Apr 14 '15 at 12:52

score 0 · Accepted Answer · answered Apr 14 '15 at 12:53

0

In this case the only possible null variable can be conn all the other variables are instantiated using literals or using methods that don't return null (they will throw exceptions if something is wrong).

answered Apr 14 '15 at 12:53

Titus

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NullPointerException - why?

2 Answers2