Recursively listing directories

Note that this code is OS Agnostic (just because I am using File.separator instead of "//"), it has been tested on windows as well as Linux. Compile it as JAR and provide the directory name to iterate as sys.argv[0] and filename to store all the listing as sys.argv[1] . If using eclipse, refer to my previous post on how to provide the arguments in eclipse to a program -- it is very simple, just go to run configuration and you will find "arguments" there only.

This will list complete directory structure in my centos machine:
java -jar readDir2.jar / allFiles.txt


import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

class dirTraversal{

public void traverseDir(String parentDir, String filename) throws IOException
{

File f = new File(parentDir);
FileWriter filewriter = new FileWriter(filename);
try {
listDir(f,filewriter);
filewriter.flush();
filewriter.close();
} catch (IOException e) {e.printStackTrace();}

}


private void listDir(File dirObject, FileWriter writer) throws IOException
{
String[] files;
files = dirObject.list();
for (String file:files)
{
File testDir = new File(dirObject + File.separator + file);
boolean isDir = testDir.isDirectory();
if(isDir == true)
{
writer.write("Directory Content for dir: " + testDir + "\n");
listDir(testDir,writer);
}
else
{
writer.write(file+ "\n");
}
}

}
}

public class readDir
{
public static void main(String[] args) throws IOException
{
dirTraversal obj = new dirTraversal();
obj.traverseDir(args[0], args[1]);

}
}