Till java 6 there is no such direct method to hide a file.
In Unix - name of hidden file or directory name must start with a period (.)
In windows - For hiding file or directory , we must set the 'hidden' attribute to active in filesystem.
> For hiding in window use following CMD command -
attrib +h [file/directory]
| 
C:\Users\ankitmittal01>attrib  +h  c:\myFile.txt | 
> For unHiding in window use following CMD command -
attrib -h [file/directory]
| 
C:\Users\ankitmittal01>attrib  -h  c:\myFile.txt | 
We may use above commands to hide or unHide file or directory
Program to hide file till java 6  >
We must write a java program that could execute CMD command.
| 
//Hide file; 
Process process = Runtime.getRuntime().exec("cmd.exe /c attrib +h c:/myFile.txt"); | 
| 
import java.io.File; 
import java.io.IOException; 
/** JavaMadeSoEasy.com */ 
public class HideFile { 
    public static void main(String... args) {     
           String fileName = "c:/myFile.txt"; 
           File fileToBeHidden = new File(fileName); 
           try { 
                  //Hide file; 
                  Process process = Runtime.getRuntime(). 
                                           exec("cmd.exe /c attrib +h c:/myFile.txt"); 
                  //wait for process to get over (i.e. for file hiding) 
                  process.waitFor(); 
           } catch (IOException e) { 
                  e.printStackTrace(); 
           } catch (InterruptedException e) { 
                  e.printStackTrace(); 
           } 
           //Now, let's test whether file has been hidden or not 
        boolean fileHidden = fileToBeHidden.isHidden(); 
           if(fileHidden) 
                  System.out.println(fileName+" is hidden "); 
           else 
                  System.out.println(fileName+" isn't hidden "); 
    } 
} 
/* OUTPUT 
c:/myFile.txt renamed successfully to c:/myFileRenamed.txt 
*/ | 
unHide file till java 6  >
| 
//unHide file 
Process process = Runtime.getRuntime().exec("cmd.exe /c attrib -h c:/myFile.txt");           | 
We must read other File operations like - create, copy, move, rename, delete, exist?, append, Hide, creation/lastModified/lastAccessed date, compare, size, Read only and writable.
RELATED LINKS>
Create File using createNewFile() method in java file IO
Program to Create Directory - Single and multiple (i.e. parent and child directories) in java file IO
2 Program to Delete a Directory
Traverse a Directory (all sub-directories and files) in 2 ways
Labels:
Core Java
File IO/File handling