Date: Tue, 13 Oct 1998 12:44:35 -0600
From: Roger Hoover <###@###.###>
To: guy.steele@East
Subject: InputStream semantics

While running the VolanoMark server benchmark under
our class libraries we have observed behavior that
we thought was illegal, but seems to be accepted by
jdk1.2beta4. We would like a definitive answer as
to whether or not the following is acceptable.

The code in question causes the following sequence
of operations to take place:
java.io.FilterInputStream.mark(), this=java.io.DataInputStream@727cbec5,
this.in=java.io.BufferedInputStream@721cbec5, [Thread[Receiver-181,5,main]]

java.io.FilterInputStream.close(), this=java.io.DataInputStream@727cbec5,
this.in=java.io.BufferedInputStream@721cbec5, [Thread[Receiver-181,5,main]]

java.io.FilterInputStream.mark(), this=java.io.DataInputStream@727cbec5,
this.in=java.io.BufferedInputStream@721cbec5, [Thread[Receiver-181,5,main]]

java.io.FilterInputStream.close(), this=java.io.DataInputStream@727cbec5,
this.in=java.io.BufferedInputStream@721cbec5, [Thread[Sender-181,5,main]]

Note that these four operations are on the same InputStream, with
a mark() and close() following the first close() operation.

According to _The_Java_Language_Specification_, p. 682,
"A closed stream cannot perform input operations and
cannot be reopened." Our runtime enforces this for the
InputStream operation mark().

Looking at the jdk1.2beta4/docs/api/java/io/InputStream.html#close(),
I see that the above prohibition is not mentioned. Can
you come up with a specification of exactly which calls are
valid after a stream is closed?