java.lang.NullPointerException
This problem has been bothering me for quite a long time now. I created a class to handle all databse transactions. I am using postgresql on jboss 4.0.2. In fact this class is used in a web service. But whenever a query is executed (or updated) I get a NullPointerException. I cannot figure out why. I tried something similar in a java standalone program and it was workinig fine. I was wondering if this was an issue particular to JBoss.
Here is my code:-
import java.sql.*;
public class Transaction {
private Connection conn;
private Statement s;
private ResultSet rs;
public boolean commit() throws SQLException{
conn.commit();
return true;
}
public boolean rollback() throws SQLException{
conn.rollback();
return true;
}
public boolean close() throws SQLException{
if (conn!=null) conn.close();
return true;
}
public Transaction(){
try{
Class.forName("org.postgresql.Driver");
log.info("Driver found");
}
catch(ClassNotFoundException e){}
try {
conn=DriverManager.getConnection("jdbc:postgresql://localhost/dbname","username","password");
}
catch(SQLException e){e.printStackTrace();}
finally {
try{
if (conn!=null) conn.close();
}catch(SQLException e){}
}
}
public int update(String query) throws SQLException{
s=conn.createStatement();
int t=s.executeUpdate(query);
s.close();
return t;
}
public ResultSet select(String query) throws SQLException{
rs=s.executeQuery(query);
return rs;
}
}
The following is part of the stack trace:-
22:49:54,844 INFO [STDOUT] java.lang.NullPointerException
22:49:54,845 INFO [STDOUT] at data.Transaction.update(Unknown Source)
22:49:54,845 INFO [STDOUT] at CustomerBooking.addCustomer(CustomerBooking.java:30)
22:49:54,846 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
22:49:54,846 INFO [STDOUT] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
22:49:54,846 INFO [STDOUT] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)