Solved

Null pointer exception when setting up a global oracle data source

Posted on 2009-06-30
6
524 Views
Last Modified: 2012-05-07
Hi,

In the following code i am trying to create a global oracle connection. But I am getting a null pointer exception when setting the oracle url. Any ideas why, also what is the best practise of creating a global database connection which can be used in all parts of the code
public class CheckFirst {
  
 
 
// Set up Oracle Data Structures
 
public static OracleDataSource ods;
public static Connection conn; 
public static ResultSet rset;
public static Statement stmt;
 
//Set up Teradata Data Structures
 
 
 
public static void openOrclConn()
{
	try
    {	
	ods.setURL("jdbc:oracle:thin:@//alpha.beta.abc.com:1521/alpha");
	ods.setUser("abc123");
	ods.setPassword("abc123");		
	ods.getConnection();
	conn.setAutoCommit (false);
	stmt = conn.createStatement ();
    } catch (Exception e) {
        e.printStackTrace();
   }
}
 
public static void closeOrclConn()
{
	try
    {
	rset.close();
	stmt.close();
	conn.close();
    } catch (Exception e) {
        e.printStackTrace();
   }
}
 
 
public static void main (String args []) 
 
{
	
	openOrclConn();
	
}
 
}

Open in new window

0
Comment
Question by:anshuma
  • 3
  • 3
6 Comments
 
LVL 2

Expert Comment

by:sirtam
ID: 24748235
Hi.

Could you please post the error message?
0
 

Author Comment

by:anshuma
ID: 24749356
java.lang.NullPointerException
      at CheckFirst.openOrclConn(CheckFirst.java:58)
      at CheckFirst.main(CheckFirst.java:87)

The line numbers can be off a little bit because I removed two three lines when I posted the code

Its happening in this line

      ods.setURL("jdbc:oracle:thin:@//bia.vip.ebay.com:1521/bia");


0
 

Author Comment

by:anshuma
ID: 24749437
ok this is what i did and it seems to have fixed it

I added the line

ods = new OracleDataSource();  in the function

public static void openOrclConn()
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 2

Expert Comment

by:sirtam
ID: 24749698
Yes, you cannot open an object before making it.

When you are using object like this the variable will be there, but empty, therefore you will get an null pointer.

And a tip:
If possible I would try to declare the variables  ods, conn, rset and stmt as not static.
If you use static variables you say its only one (ever) object of it, and that can make problems later.
0
 
LVL 2

Accepted Solution

by:
sirtam earned 500 total points
ID: 24749714
But to make this work you'll have to make all the mothods (except main) not static too. Dont bother fixing it if it works.

An example how to write it:
public class CheckFirst {
  
 
 
// Set up Oracle Data Structures
 
public OracleDataSource ods;
public Connection conn; 
public ResultSet rset;
public Statement stmt;
 
//Set up Teradata Data Structures
 
 
 
public void openOrclConn()
{
        try
    {   
        ods = new OracleDataSource();
        ods.setURL("jdbc:oracle:thin:@//alpha.beta.abc.com:1521/alpha");
        ods.setUser("abc123");
        ods.setPassword("abc123");              
        ods.getConnection();
        conn.setAutoCommit (false);
        stmt = conn.createStatement ();
    } catch (Exception e) {
        e.printStackTrace();
   }
}
 
public void closeOrclConn()
{
        try
    {
        rset.close();
        stmt.close();
        conn.close();
    } catch (Exception e) {
        e.printStackTrace();
   }
}
 
 
public static void main (String args []) 
 
{
        
        openOrclConn();
        
}
 
}

Open in new window

0
 

Author Closing Comment

by:anshuma
ID: 31598463
Thanks alot for this
0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Introduction This article is the last of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article covers our test design approach and then goes through a simple test case example, how …
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
Video by: Michael
Viewers learn about how to reduce the potential repetitiveness of coding in main by developing methods to perform specific tasks for their program. Additionally, objects are introduced for the purpose of learning how to call methods in Java. Define …
Viewers will learn about arithmetic and Boolean expressions in Java and the logical operators used to create Boolean expressions. We will cover the symbols used for arithmetic expressions and define each logical operator and how to use them in Boole…

761 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question