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try{
            AccountDAOImpl adi = new AccountDAOImpl();
            Account a = new Account();
            a = adi.getAccount(account, depositamt);
            a.setBalance(a.getBalance() + a.getDepositamt());
            adi.update(account);
            }catch(Exception ex){
                ex.printStackTrace();
            }
}


im getting a null point exception in above code 5th line.-> a.setBalance(a.getBalance() + a.getDepositamt());

Please tell me a solution for this


Updates by OP(3h later)

can I do this :

if(a!=null){
            a.setBalance(a.getBalance() + a.getDepositamt());
            adi.update(account);
            }else {
                adi.update(account);
            }
Posted 13-Jun-13 18:24pm
Edited 13-Jun-13 23:05pm
TorstenH.34.8K
v2
Comments
Member 10566327 at 3-Feb-14 2:11am
   
why we should handle the NullpointerException in if block only why not in trycatch block.give me the answer
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Solution 1

You should understand the basics first. Following are the possible causes when program throws NullPointerException[^].
  • When you call instance method on a null object. you won't get null pointer exception if you call static method or class method on null object because static method doesn't require an instance to call any method.
  • While accessing or changing any variable or field on null object.
  • Throwing null when an Exception is expected to throw.
  • When calling length of array when array is null.
  • Accessing or changing slots of null just like an array.
  • When you try to synchronize on null object or using null inside synchronized block in Java

Following are the checkpoints to resolve this issue:
  • Identify the line where it occurred.
  • Ask "what objects (or arrays) are being referenced on this line". One of them is null and it's usually obvious which.
  • Figure out why it's null.

You can also check:
How to : Avoid Null Pointer Exception in Java[^]
Why do I get a NullPointerException?[^]



--Amit
  Permalink  
Comments
Sergey Alexandrovich Kryukov at 7-Jul-13 23:22pm
   
Well explained, a 5.
—SA
_Amy at 12-Jul-13 21:31pm
   
Thank you Sergery. :)
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Solution 3

What you can do is debugging:

Debugging with Eclipse[^]

Debugging with Netbeans[^]

Seams like one of the values is NULL:

- a (whatever "a" is... please use better names)
- return value of a.getBalance()
- return value of a.getDepositamt()

So you should check the values by debugging.
  Permalink  
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Solution 2

can I do this :

if(a!=null){
            a.setBalance(a.getBalance() + a.getDepositamt());
            adi.update(account);
            }else {
                adi.update(account);
            }
  Permalink  

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

  Print Answers RSS
0 Mika Wendelius 460
1 DamithSL 353
2 OriginalGriff 315
3 Sergey Alexandrovich Kryukov 179
4 Afzaal Ahmad Zeeshan 169


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