why construct file with "", the path of the file return "/"?

[junzhang1983]

l am a little puzzled, why the file's behavior like this:

File fl = new File("","1.txt");
System.out.println(fl.getName());
System.out.println(fl.getParent());
System.out.println(fl.getPath());
System.out.println(fl.getAbsolutePath());
try {
System.out.println(fl.getCanonicalPath());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}