This bug was found by St.Petersburg Java SQE team (by Alexander Kuzmin).

If path is null, constructor java.io.FileOutputStream(String path) throws
NullPointerException, but specification doesn't mention this.

The Java Language Specification Version 1.0

22.16.1 public FileOutputStream(String path)
throws SecurityException, FileNotFoundException

This constructor initializes a newly created FileOutputStream by opening a connection to an actual file, the file
named by the path name path in the file system. A new FileDescriptor object is created to represent this file
connection.

First, if there is a security manager, its checkWrite method (§20.17.21) is called with the path argument as its
argument.

If the actual file cannot be opened, a FileNotFoundException is thrown.

_______________________Example ______________________________________

import java.io.*;

public class badtests {

  public static void main( String argv[] ) {

   String s=null;
   FileOutputStream testfile;
 
    try {
    testfile=new FileOutputStream(s);
    }
  catch (SecurityException e)
  {System.out.println("SecurityException - all OK !");}

  catch (FileNotFoundException e)
  {System.out.println("FileNotFoundException - all OK !");}
 
  catch (Exception e)
  {System.out.println(" Unexpected "+e+" thrown ");}

  }

}
______________________ Output ______________________________________

Unexpected java.lang.NullPointerException thrown
____________________________________________________________________