Name: saf@russia Date: 09/06/96


This bug was found by St.Petersburg Java SQE team (by Stanislav Avzan).

The java.io.PipedInputStream.read(b,off,len) method does not work with null
value of b according to the Java language specification.

The Java Language specification
(Version 1.0 - August 1, 1996)
says the following (please see item 22.3.3):

22.3.3 public int read(byte[] b, int off, int len)
throws IOException, NullPointerException,
IndexOutOfBoundsException

The general contract of read(b, off, len) is that it reads some number
of bytes from the input stream and stores them into the buffer array b. An
attempt is made to read as many as len bytes, but a smaller number may
be read, possibly zero. The number of bytes actually read is returned as
an integer.

This method blocks until input data is available, end of file is detected, or
an exception is thrown.

If b is null, a NullPointerException is thrown. <.....>"

So this method should throw NullPointerException
if b is null.
But in fact when len equals to 0 it does not.
 
Here is the minimized test demonstrating the bug:
    

----- test3.java ---------------------------------------
import java.io.*;

public class test3 {

   public static void main( String[] argv ) {
     PipedOutputStream os = new PipedOutputStream();
     PipedInputStream is = new PipedInputStream();
     try {
       is.connect(os);
     } catch(Throwable e) {
       System.out.println("Test failed: unexpected <"+e+"> thrown");
     }
 
     try {
       is.read(null,0,0);
       System.out.println("Test failed: NullPointerException expected");

     } catch(NullPointerException e) {
       System.out.println("Test passed: NullPointerException thrown");
     } catch(Throwable e) {
       System.out.println("Test failed: unexpected <"+e+"> thrown");
     }
   }
}

----- The output of the test: -------------------------

$JAVA test3
Test failed: NullPointerException expected

-------------------------------------------------------


Workaround:
None
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