Jetty 12 - use JVM provided null OutputStream

[joakime]

Turns out we really only used our Null OutputStream and Null Writer from test cases.

So just use the JVM provided ones instead.

[sbordet]

Why this try/catch block?

[joakime]

Because InputStream.close() throws IOException, and your InputStreamResponseListener.getInputStream() does not.

• https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/io/InputStream.html#close()

[sbordet]

@joakime I don't understand. There is no need to close this stream here. And InputStreamResponseListener.getInputStream() returns a plain InputStream whose close() throws IOException.

[joakime]

The Javadoc for InputStreamListener.getInputStream() says ..

• The method may be invoked only once; subsequent invocations will return a closed {@link InputStream}.

This makes sure that the API contract is still satisfied, and also ensures that use of this "second use" InputStream returned correctly produces IOExceptions on any of the read methods indicating that the stream is closed already.

[joakime]

@sbordet bump, are you ok with this now? (the code changed here too, a better approach proposed by @gregw)

[joakime]

$ jshell
|  Welcome to JShell -- Version 11.0.16
|  For an introduction type: /help intro

jshell> InputStream.nullInputStream();
$1 ==> java.io.InputStream$1@3d646c37

jshell> $1.read()
$2 ==> -1

jshell> $1.close()

jshell> $1.read()
|  Exception java.io.IOException: Stream closed
|        at InputStream$1.ensureOpen (InputStream.java:86)
|        at InputStream$1.read (InputStream.java:98)
|        at (#4:1)

jshell> /exit
|  Goodbye

[joakime]

$ jshell
|  Welcome to JShell -- Version 11.0.16
|  For an introduction type: /help intro

jshell> new BufferedInputStream(new ByteArrayInputStream(new byte[] { 0x01 }))
$1 ==> java.io.BufferedInputStream@26a1ab54

jshell> $1.read()
$2 ==> 1

jshell> $1.close()

jshell> $1.read()
|  Exception java.io.IOException: Stream closed
|        at BufferedInputStream.getBufIfOpen (BufferedInputStream.java:176)
|        at BufferedInputStream.fill (BufferedInputStream.java:220)
|        at BufferedInputStream.read (BufferedInputStream.java:271)
|        at (#4:1)

jshell> /exit
|  Goodbye

[joakime]

and ...

$ jshell
|  Welcome to JShell -- Version 11.0.16
|  For an introduction type: /help intro

jshell> var fi = new FileInputStream(new File("/tmp/foo.txt"))
fi ==> java.io.FileInputStream@26a1ab54

jshell> fi.read()
$2 ==> 70

jshell> fi.close()

jshell> fi.read()
|  Exception java.io.IOException: Stream Closed
|        at FileInputStream.read0 (Native Method)
|        at FileInputStream.read (FileInputStream.java:231)
|        at (#4:1)

jshell> /exit
|  Goodbye

[sbordet]

@joakime I don't understand. There is no need to close this stream here. And InputStreamResponseListener.getInputStream() returns a plain InputStream whose close() throws IOException.