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Problem running a program practicing with Arrays and Classes

Brandon Peeples
Ranch Hand

Joined: Jan 06, 2010
Posts: 38
Hello all. I am having a problem running my program. It produces no output and goes on infinitely. I can't figure out what the problem is. Any help spotting anything unusual with my code would be appreciated. Thanks.




EDIT: Added a main method
Joe Boman
Greenhorn

Joined: Dec 10, 2009
Posts: 20
Hello Brandon,
Are you using a debugger? If so have you set breakpoints in your code?
Let us know/thanks
Joe Boman
Greenhorn

Joined: Dec 10, 2009
Posts: 20
It definitely compiles, however I am getting the following error message when I attempt to execute it:

Exception in thread "main" java.lang.NoSuchMethodError: main

A Google of that error message indicates:
"The Java VM requires that the class you execute with it have a main method at which to begin execution of your application. discusses the main method in detail."
pete stein
Bartender

Joined: Feb 23, 2007
Posts: 1561
Joe Boman wrote:It definitely compiles, however I am getting the following error message when I attempt to execute it:

Exception in thread "main" java.lang.NoSuchMethodError: main

So which line causes the exception?
Siddhesh Deodhar
Ranch Hand

Joined: Mar 05, 2009
Posts: 117
Dear, your class is public...

public class LetterInventory{}

Where is your main method ?

public static void main(String args[]) ?


Good, Better, Best, Don't take rest until, Good becomes Better, and Better becomes Best.
Sidd : (SCJP 6 [90%] )
Brandon Peeples
Ranch Hand

Joined: Jan 06, 2010
Posts: 38
Thanks for the replies. I should have mentioned the fact that main is in a different class called "LetterInventoryMain.java" . I tried to execute the program from a different class using the object from "LetterInventory.java" . I think I will just make a main method in the class I posted instead. I'll see if I get some output that way. I'll post an update once I try.
Joe Boman
Greenhorn

Joined: Dec 10, 2009
Posts: 20
I think it is looping in the for loop in the class constructor.

Hope it's ok that I dummied up a "main" module and instantiated the class passing it the string "ABCDE". As a result, the for loop is repeatedly building in lower case "abcdeabcde...etc...etc".

I don't know what this class is supposed to do, but ,but I have a feeling that class behavior may not be intended?

Here is the "main" I added at the bottom of the class:
Brandon Peeples
Ranch Hand

Joined: Jan 06, 2010
Posts: 38
I appreciate the feedback Joe. The class is supposed to accept a String and report the amount of letters (in brackets) in the String ignoring the case and all non alphabetic characters. For example:

LetterInventory inventory1 = new LetterInventory("Pizza123");

should produce: "[aipzz]"


Joe Boman
Greenhorn

Joined: Dec 10, 2009
Posts: 20
Sure, NP Brandon,

When I modify main to pass the string "Pizza123" (which does include numbers), the constructor is carrying out the same unfortunate looping behavior. No change in behavior with numbers.

I don't want to provide suggestions on how to fix this, but the problem became more clear to me when I executed it line by line in a debugger. I like to cheat that way

I use BlueJ, but that's only because it is familiar to me.
thanks/Joe
Brandon Peeples
Ranch Hand

Joined: Jan 06, 2010
Posts: 38
Ahhh thanks Joe. I think I'll give the debugger a try. I am currently using Eclipse for the first time. I know there is a debugger and I'll try to use it. I previously used something without a debugger.
 
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