•
•
•
•
What is DaniWeb IT Discussion Community?
You're currently browsing the Java section within the Software Development category of DaniWeb, a massive community of 427,331 software developers, web developers, Internet marketers, and tech gurus who are all enthusiastic about making contacts, networking, and learning from each other. In fact, there are 3,163 IT professionals currently interacting right now! Registration is free, only takes a minute and lets you enjoy all of the interactive features of the site.
Please support our Java advertiser: Lunarpages Java Web Hosting
Views: 1113 | Replies: 4
 |
•
•
Join Date: Feb 2007
Location: india
Posts: 52
Reputation: 
Rep Power: 2
Solved Threads: 0
Junior Poster in Training
my program is compiled.but on run that i have message "Exception in thread "main" jav
#1
Feb 7th, 2007
my program is compiled.but on run that i have message "Exception in thread "main" java.lang.NullPointer Exception"
1. class Rev
2. {
3. char a[];
4. char i=3;
5. void str()
6. {
7. for(i='A';i<'D';i++)
8. {
9. a[i]='i';
10. }
11. }
12. void show()
13. {
14. for(int i='A';i<'D';i++)
15. {
16. System.out.print(a[i]);
17. }
18. }
19. void reversStr()
20. {
21. for(i='A';i<'D';i++)
22. {
23. System.out.print(a[i]);
24. }
25. }
26. }
27. class Revers
28. {
29. public static void main(String[] args)
30. {
31. Rev a1=new Rev();
32. a1.str();
33. a1.show();
34. a1.reversStr();
35. }
36. }
37. plz run and solve the problem
1. class Rev
2. {
3. char a[];
4. char i=3;
5. void str()
6. {
7. for(i='A';i<'D';i++)
8. {
9. a[i]='i';
10. }
11. }
12. void show()
13. {
14. for(int i='A';i<'D';i++)
15. {
16. System.out.print(a[i]);
17. }
18. }
19. void reversStr()
20. {
21. for(i='A';i<'D';i++)
22. {
23. System.out.print(a[i]);
24. }
25. }
26. }
27. class Revers
28. {
29. public static void main(String[] args)
30. {
31. Rev a1=new Rev();
32. a1.str();
33. a1.show();
34. a1.reversStr();
35. }
36. }
37. plz run and solve the problem
•
•
Join Date: Dec 2004
Location: London or Slovakia
Posts: 2,467
Reputation:
Rep Power: 11
Solved Threads: 296
Re: my program is compiled.but on run that i have message "Exception in thread "main"
#2
Feb 7th, 2007
I think you should reconsider your for loop
I never heard that in java you can increase value of character type variable, this is possible but in Perl
Create array of characters and with use of "i" get the character from the array
so if char[] myArray = { 'A', 'B', 'C'}
then if i = 1
you get character B
for(i='A';i<'D';i++)
I never heard that in java you can increase value of character type variable, this is possible but in Perl
Create array of characters and with use of "i" get the character from the array
so if char[] myArray = { 'A', 'B', 'C'}
then if i = 1
you get character B
Learn to see in another's calamity the ills which you should avoid.
Publilius Syrus
(~100 BC)
If we helped you to solve your problem, answered your question please mark your post as SOLVED.
Publilius Syrus
(~100 BC)
If we helped you to solve your problem, answered your question please mark your post as SOLVED.
•
•
Join Date: Nov 2005
Posts: 72
Reputation:
Rep Power: 3
Solved Threads: 5
Junior Poster in Training
Re: my program is compiled.but on run that i have message "Exception in thread "main"
#3
Feb 7th, 2007
Oh my.
For one, I think this is how you meant to represent your code:
And, I get the error because you're trying to access an array element without having defined the size of the array.
So, define a length for the array at the start of class Rev:
You're still going to end up with issues, such as java.lang.ArrayIndexOutOfBoundsException: 65 when you try to access a['A'] and so on, because 'A' as a char is 65 as an integer, and integers are what you want to work with when accessing arrays.
I have no idea what your program's trying to do, but those are some thing to consider.
For one, I think this is how you meant to represent your code:
java Syntax (Toggle Plain Text)
And, I get the error because you're trying to access an array element without having defined the size of the array.
void str() {
for(i='A';i<'D';i++) {
a[i]='i'; // ERROR OCCURS HERE
}
}So, define a length for the array at the start of class Rev:
char[] a = new char[(some integer)];You're still going to end up with issues, such as java.lang.ArrayIndexOutOfBoundsException: 65 when you try to access a['A'] and so on, because 'A' as a char is 65 as an integer, and integers are what you want to work with when accessing arrays.
I have no idea what your program's trying to do, but those are some thing to consider.
synchronized (theWorld) { System.out.println ("It's all mine..."); }
How many people have code in their Sigs?
How many people have code in their Sigs?
•
•
Join Date: Feb 2007
Location: india
Posts: 52
Reputation:
Rep Power: 2
Solved Threads: 0
Junior Poster in Training
Re: my program is compiled.but on run that i have message "Exception in thread "main"
#4
Feb 7th, 2007
thank you very much
•
•
Join Date: Feb 2007
Location: india
Posts: 52
Reputation:
Rep Power: 2
Solved Threads: 0
Junior Poster in Training
Re: my program is compiled.but on run that i have message "Exception in thread "main"
#5
Feb 7th, 2007
i m very thankfull 4 r u r help
|
•
•
•
•
•
•
•
•
DaniWeb Java Marketplace
•
•
•
•
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Linear Mode
- Exception in thread "main" java.lang.NoClassDefFoundError: Invaders Error (Java)
- exception in thread "main" java.lang.NoClassDefFoundError (Java)
- Exception in thread "QueuedExecutor" (Java)
Other Threads in the Java Forum
- Previous Thread: urgent jdbc code
- Next Thread: Practice Programs
