UNIX Domain Socket in Java

Question

I see these threads UNIX socket implementation for Java? and http://forums.sun.com/thread.jspa?threadID=713266.

The second link says that Java already supports UNIX Domain Socket. If that's true what class do I need to implement from Java?.

From the first link, it says that Java does not support UNIX Domain Socket. If you need UNIX Domain Socket you must use a 3rd-party library.

So, which is it?

The second link (forums.sun.com) is broken and seems to lead to some nowhere leading page of Oracle. No archive.org found, BTW, sadly. — Tino, May 23 '15 at 19:21

score 24 · Answer 1 · edited May 13 '16 at 12:56

24

You could use junixsocket: https://github.com/kohlschutter/junixsocket

It provides AF-UNIX support via a JNI library, utilizing the Java Socket API. It even allows connecting to MySQL from Java (Connector/J) via Unix sockets.

edited May 13 '16 at 12:56

Aleksander Blomskøld

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answered May 10 '11 at 18:23

Christian Kohlschütter

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As at Nov 2015, the *junixsocket* project resides at https://github.com/kohlschutter/junixsocket – VirtualMichael Nov 04 '15 at 05:55
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Be careful, it only supports Unix sockets in STREAM mode. Check what your server opens, with `netstat -ux`. See also [Difference between UNIX domain STREAM and DATAGRAM sockets](http://stackoverflow.com/questions/13953912). – Florian Mar 16 '17 at 15:43

score 17 · Accepted Answer · answered Nov 04 '10 at 21:03

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Java cannot create or access Unix Domain Sockets without using a 3rd party (native) library. The last comment on the second link above mentions this.

The first link has some good (and correct) information on it.

answered Nov 04 '10 at 21:03

nogudnik

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As of Java 16, Unix domain sockets are supported natively java with SocketChannel / ServerSocketChannel API. – Benny May 26 '21 at 17:20

score 7 · Answer 3 · answered Apr 17 '15 at 13:48

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Netty also supports it since version 4.0.26: https://github.com/netty/netty/pull/3344

answered Apr 17 '15 at 13:48

Leo Gomes

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Be careful, it only supports Unix sockets in STREAM mode. Check what your server opens, with `netstat -ux`. See also [Difference between UNIX domain STREAM and DATAGRAM sockets](http://stackoverflow.com/questions/13953912). – Florian Mar 16 '17 at 15:44
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Please note Netty 4.0 only support `epoll(2)` for Unix domain socket, this means it can't be used without Linux. – Low power Mar 22 '20 at 13:34

score 3 · Answer 4 · answered Sep 21 '21 at 20:03

As noted by @Benny in a comment, JDK 16 comes with built-in support for unix domain sockets via java.net.UnixDomainSocketAdress and related classes. You can read more at JEP-380

Here's a snippit from the JEP:

var unixAddr = UnixDomainSocketAddress.of("/foo/bar.socket");
var channel2 = SocketChannel.open(unixAddr);

UNIX Domain Socket in Java

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