Description Amin Ahmad 2010-12-08 19:36:33 EST

Build Identifier: Build id: M20100211-1343

A file's last modified date is Fri Jun 29 17:31:44 PDT 1956. Jetty ends up setting the Last-Modified header to "Sat, 30 Jun 1956 .-:.(:/* GMT". Here's the reason why:

1) When Jetty serves a file, it copies the files last modified date into the Last-Modified header.
2) Jetty uses java.io.File.lastModified() to retrieve the last modified date.
3) This value is negative in the sample case (specifically, -426209296000), and Jetty chokes, in the following manner:
  a) Response.setDateHeader passes the negative date into HttpFields.putDateField, which delegates formatting to the formatDate method.
  b) The local variables hours, minutes, and seconds all evaluate to negative values (algorithm is not designed to handle negative input), and when these values are passed to the methods StringUtil.append2digits, which is defined thusly:

267     public static void append2digits(StringBuffer buf,int i)
268     {
269         if (i<100)
270         {
271             buf.append((char)(i/10+'0'));
272             buf.append((char)(i%10+'0'));
273         }
274     }

the cast to char ends up producing characters below '0'. Note that the guard on line 269 really isn't sufficient: i must also be non-negative.

Reviewing the Javadoc for File.lastModified doesn't appear to rule out returning negative values (unless you read into the word "since"), so I would classify this as a Jetty bug.



Reproducible: Always

Steps to Reproduce:
1. Create a file with a last modified date before 1970.
2. Access the file via Jetty HTTP.
3. Examine the Last-Modified header. It will be invalid.