What is the problem accessing "C" drive using a code (using import.io.*; )?

CoderForEver

Come on guys. My question is how can I find a file in "C", not in "C:\someFolder"? ... on the latter case it works easily. If you have time try to run my code, it really works. But try to make the searching folder "C:\" not "C:\someFolder". Then it will through an exception. Though thank you for your help

Luc Pattyn

Hi, some comments: 1. you should implement error handling in your code; have a try-catch and log the exception. 2. when an exception occurs, it gives the number of the offending line; that is where the problem shows itself, the actual cause may be somewhat sooner. 3. when the exception occurs in a method call, check the documentation for that method to see what it has to say about the specific exception. That should tell you exactly what is wrong. 4. Your searchForFile() method is a bit silly, it tells whether a file exists, but when it does, it does not tell you where it is. A better definition of it would return the path to the first occurence it finds as a string. :)

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Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.

jschell

CoderForEver wrote:

It throws a NullPointerException

The stack trace tells you where. So which line is it?

CoderForEver wrote:

the application may not have an access on hard

Application? You are running exactly the code you posted from a console window correct? Thus the only way it wouldn't have access is if you you, the user, doesn't have permission to access the C drive root. And if that was the case then you should see an exception that indicates exactly that - a permission problem.

jschell

TorstenH. wrote:

...you know, you need to mask the double-slash ?

And do you know that the OP code doesn't need to do that correct? The code has "C:\\" which is exactly what it should have to access the C drive root.

TorstenH. wrote:

String strSearchFolder = "C:\\\\someFolder"; // add extra slashes to make it a double slash

Which resolves to "C:\\someFolder" which although it will work on windows is not any better or more correct than "C:\someFolder".

jschell

What is the result of running the following? If it is exception then post the entire stack trace.

File file1=new File("C:\\\\");
System.out.println("exists=" + file1.exists());

Lost User

Consider these lines:

	File\[\] list=file1.listFiles();
		for(File x: list)

if file1.listfiles() does not return any items then list will be null and the runtime will throw an exception. Took me less than 5 minutes to find it with the debugger. Lesson: Check return values and statuses, and catch exceptions: there is no alternative.

The best things in life are not things.

David Skelly

This works for me. As someone else has pointed out, file1.listFiles() may return null so you need to allow for that.

Lost User

I am reduced to "someone else". :((

The best things in life are not things.

Nagy Vilmos

This would show the original problem if C:\\someFolder was empty.

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Lost User

Exactly how I found the problem.

The best things in life are not things.

David Skelly

Interesting. When I run it on an empty directory, I get a zero-length array. Also, it doesn't make any difference if I put "C:\\someFolder" or "C:\\someFolder\\". It behaves the same in both cases. I only get null back if there is some kind of problem (e.g. Access denied).

Lost User

I'll try it again sometime and check the results more closely.

The best things in life are not things.