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Getting 'null' value in response to statement.executeUpdate method

Nikhil B. Singh
Greenhorn

Joined: May 20, 2012
Posts: 18
Hello,

I am trying to insert few records in to mysql database. As i can successfully able to establish connection with server but not able to insert a single record through net beans ide gui interface or front end.

The code which i wrote for connection is encapsulated in Constructor method and in event handler i have written code to insert data. this code is as follows:


in this it throws an exception error and "r" yields null. I am confused where the hell i have made mistake that it is giving me null as output instead of 0 or 1.

Thank you!
Nicola Garofalo
Ranch Hand

Joined: Apr 10, 2010
Posts: 308
Could you please post the exception message, if any, and exception type?


Bye,
Nicola
Nikhil B. Singh
Greenhorn

Joined: May 20, 2012
Posts: 18
Hi..!!

actually i wrote these code in try -catch block, so it is not generating much verbose however as i have use stack trace method it generates following messaga: Ljava.lang.StackTraceElement;@d49271

Thank you for quick response.!!

Nicola Garofalo
Ranch Hand

Joined: Apr 10, 2010
Posts: 308
Nikhil B. Singh wrote:Hi..!!

actually i wrote these code in try -catch block, so it is not generating much verbose however as i have use stack trace method it generates following messaga: Ljava.lang.StackTraceElement;@d49271

Thank you for quick response.!!



If you can't debug your code just add after line 53:



And see what is printed on your output. You should see the exception type, and probably where exactly it has been generated.
Nikhil B. Singh
Greenhorn

Joined: May 20, 2012
Posts: 18

.
.
.
If you can't debug your code just add after line 53:



And see what is printed on your output. You should see the exception type, and probably where exactly it has been generated.



I am sorry, i could not get understand much from this, if you don't mind, would you please help me to catch the error source.

Thank you!
Nicola Garofalo
Ranch Hand

Joined: Apr 10, 2010
Posts: 308
Nikhil B. Singh wrote:Hi..!!

actually i wrote these code in try -catch block, so it is not generating much verbose however as i have use stack trace method it generates following messaga: Ljava.lang.StackTraceElement;@d49271

Thank you for quick response.!!



Anyway
getStackTrace() method returns an array of StackTraceElement.
So it's useless to print it out or use it as a message for a message Panel.
Nicola Garofalo
Ranch Hand

Joined: Apr 10, 2010
Posts: 308
Much more clearer now

See your class StudentInformation.java at line 327.

What are you doing there? What instructions are you trying to execute?
Nikhil B. Singh
Greenhorn

Joined: May 20, 2012
Posts: 18

at line 327: I am writing code to get a value from radio button. I have two radio button controls and trying to read the selected one value.



Please let me know if I am writing wrong syntax to read the value of selected radio button.

Thank you!
Nicola Garofalo
Ranch Hand

Joined: Apr 10, 2010
Posts: 308
Ok either radion button rbtn_indiv is null or rbtn_indiv.getName() is null.

did you make somewhere before line 327

rbtn_indiv = new JRadioButton(..) ?

Did you set the name of your JRadioButton?

That's the heart of your problem

Let me know if you want.





Nikhil B. Singh
Greenhorn

Joined: May 20, 2012
Posts: 18
Hi..

As you have suggested I examined that radio button code again, as generated in Net beans ide auto code generated section..

I have set the name property as i have given in radio button's text property field.

However, i am facing new kind of error, which is as follows

Uncompilable source code - variable team_t might not have been initialized.


I think, i m not reading value of selected radio button properly. Please throw some light to do perform this.

Thank you !!
Nicola Garofalo
Ranch Hand

Joined: Apr 10, 2010
Posts: 308
Nikhil B. Singh wrote:Hi..

As you have suggested I examined that radio button code again, as generated in Net beans ide auto code generated section..

I have set the name property as i have given in radio button's text property field.

However, i am facing new kind of error, which is as follows

Uncompilable source code - variable team_t might not have been initialized.


I think, i m not reading value of selected radio button properly. Please throw some light to do perform this.

Thank you !!


You must assign a value to every local variable.
So give team_t an initial value

for example:



In the code above you are always giving to String team_t the value "Individual"

Why?
Nikhil B. Singh
Greenhorn

Joined: May 20, 2012
Posts: 18
Hi..

actually i have wrote that text mistakenly. however i have improved this mistake but the code i have written here to get the value of selected radio button is not working properly. this is why it is giving null pointer exception error.

I am confused that why these people have given Label & Name property associated with any swing component. It doesn't make any sense to set Text property and Label property separately.

plus i could not resolve this when we should use getText or getSelectedObjects method for radio button or which may be appropriate for radio button to identify selected radio button.

Thanks!!
Nikhil B. Singh
Greenhorn

Joined: May 20, 2012
Posts: 18
Hi..

I have figured out the solution to read the value of selected radio button.
it is as follows:


Thank you very much for your kind support...!

With regards!

Nikhil!
Nicola Garofalo
Ranch Hand

Joined: Apr 10, 2010
Posts: 308
For future doubts you may refer to java tutorial

http://docs.oracle.com/javase/tutorial/uiswing/components/button.html

Bye,
Nicola
 
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