Java: Network is unreachable error

Ran into this error today while trying to build the docbook file for Refactoring Redmine. It looks like it’s a problem with Java IPv4 IPv6 networking on Debian. Simple solution is to edit /etc/sysctl.d/bindv6only.conf and change net.ipv6.bindv6only=1 to 0. Thanks to Roberto for the fix.

Hope this helps someone.

My error log:

Validating your document...
        at com.sun.msv.driver.textui.DebugController.printLocation(
        at com.sun.msv.driver.textui.DebugController.error(
        at com.sun.msv.reader.Controller.error(
        at com.sun.msv.reader.Controller.error(
        at com.sun.msv.reader.GrammarReader._parse(
        at com.sun.msv.reader.GrammarReader.parse(
        at com.sun.msv.schematron.reader.SRELAXNGReader.parse(
        at com.sun.msv.schematron.Driver.doMain(
        at com.sun.msv.schematron.Driver$
 There are errors in your document
relmes verifier   Copyright(C) Sun Microsystems, Inc. 2001
Network is unreachable Network is unreachable
book.pdf not rendered.