I/O - creating a directory vs. not creating a dir

[Derek Harper]

Hi guys,

I'm currently experimenting with creating files and directories. I've learned that it's good practice to "play" with code in order to gain a better understanding of how something works or doesn't work.

Take a look at the following code:

import java.io.*;
 
class NoFileDirDemo {
public static void main(String[]args) {
 
try {
File myDir = new File("dexDir");    
//myDir.mkdir();                    // call to mkdir omitted on purpose
 
File myFile = new File(myDir, "2ndFile.txt");
myFile.createNewFile();              
 
// write data to file
PrintWriter pw = new PrintWriter(myFile);
pw.write("This is just a test.");
pw.flush();
pw.close();
}
catch (IOException e){
}
}
}
 

Now when i compile the program, i expect an exception to occur because the call to "mkdir' has been purposely omitted. However, the code compiles fine. However, when i look in the 'bin' directory, the "dexDir" is not there.

My question is why didn't the program throw an exception? Is there something i did wrong or omitted from the code?

Thanks in advance.....
[ September 17, 2008: Message edited by: Derek Harper ]

[Rob Spoor]

It does throw an exception, but your ignoring that:

catch (IOException e) {
}

If you put a "e.printStackTrace()" in there you'll see the error appearing.

[Derek Harper]

Ahhh, so that's what i forgot to do.

You're exactly right because once i added the e.printStackTrace() to the code, i got the following:

java.io.IOException: The system cannot find the path specified
at java.io.WinNTFileSystem.createFileExclusively(Native Method)
at java.io.File.createNewFile(File.java:883)
at NoFileDirDemo.main(NoFileDirDemo.java:11)

Thanks Rob!