How can I disable IPv6 stack use for IPv4 IPs on JRE?

Question

As you can see on below screenshots, eclipse and Android SDK Manager (and other Java programs) are trying to connect to a IPv4 Internet IP via IPv6 TCP/IP stack while Proxifier (a proxy manager program, nevermind) can not support that.

How I can disable IPv6 in Java?

Gruel

Answer 1

I wanted to use this for some program I hadn't control for running that Java app so ended with this _JAVA_OPTIONS=-Djava.net.preferIPv4Stack=true environment variable. (read about _JAVA_OPTIONS here)

If you are using Windows, just run this command on Windows cmd:
setx _JAVA_OPTIONS -Djava.net.preferIPv4Stack=true

Thanks to Jason Nichols for reminding this JVM argument :)

Gruel

Thanks Ebrahim!! after I issued the command in Windows 8 command line, restarted Eclipse, the error from server side "Address is invalid on local machine, or port is not valid on remote machine" disappeared! Many thanks!! – Sightless

good find. it never occurred to me that an application could possibly use the v6 stack when clearly the destination host is a v4 system. sick. – Enriquetaenriquez

This is because of such stupidity that some people end up disabling IPv6 entirely from their whole operating system. – Gabbey

Agreed. Just to mention this just changes the preference AFAIK and doesn't disable whole thing, it seems Carlos answer below does that however :) – Gruel

Answer 2

Did you try (from the command line)

-Djava.net.preferIPv4Stack=true

or (from your code)

System.setProperty("java.net.preferIPv4Stack" , "true");

Arlindaarline

Answer 3

Maybe a bit late but for me neither solution worked. So I included this option as it is stated here:

-Djava.net.preferIPv4Addresses=true

But also the followingI added line to the end of the file /etc/sysctl.conf

net.ipv6.conf.all.disable_ipv6 = 1

And

sudo sysctl -p

as it is explained here. In order to check that ipv6 is disabled just execute:

ip a | grep inet

Christensen

you, Sir, made my day! Finally able to start Java Springboot Tomcat App on tcp4 Port 8090 (by defalut it was started on tcp6 Port 8090). Thanks! – Globuliferous

Well the answers did not work for me and I wasted a lot of time to find out the final solution And that is the aim of stackoverflow right?. Really appreciated but no need thanks! – Christensen