javaws produces "Network connect error" connecting to Avocent 2020

After an update to my openjdk-7-jre (to 7u95-2.6.4-0ubuntu0.14.04.1) and openjdk-7-jre-headless (to 7u95-2.6.4-0ubuntu0.14.04.1), javaws has begun producing "Network connect error" messages when I try to connect to my Avocent 2020 KVM's remote-viewing console. Attached is a screen shot showing the message. This previously worked fine (with version 7u91-2.6.3-0ubuntu0.14.04.1), and it continues to work fine from a computer that's still running the old versions. It also works OK with Oracle Java installed via ppa:webupd8team/java (oracle-java7-installer 7u80+7u60arm-0~webupd8~1). If there are log files that will provide more debugging information, please tell me and I'll be happy to attach them.

$ lsb_release -rd
Description: Ubuntu 14.04.3 LTS
Release: 14.04

$ apt-cache policy icedtea-netx
icedtea-netx:
  Installed: 1.5.3-0ubuntu0.14.04.1
  Candidate: 1.5.3-0ubuntu0.14.04.1
  Version table:
 *** 1.5.3-0ubuntu0.14.04.1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     1.5-1ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

$ apt-cache policy openjdk-7-jre
openjdk-7-jre:
  Installed: 7u95-2.6.4-0ubuntu0.14.04.1
  Candidate: 7u95-2.6.4-0ubuntu0.14.04.1
  Version table:
 *** 7u95-2.6.4-0ubuntu0.14.04.1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     7u51-2.4.6-1ubuntu4 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

$ apt-cache policy openjdk-7-jre-headless
openjdk-7-jre-headless:
  Installed: 7u95-2.6.4-0ubuntu0.14.04.1
  Candidate: 7u95-2.6.4-0ubuntu0.14.04.1
  Version table:
 *** 7u95-2.6.4-0ubuntu0.14.04.1 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     7u51-2.4.6-1ubuntu4 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages