Public bug reported: On a fresh install of Ubuntu 18.04.1 and 18.10, jgem can't install anything:
root@9adf8e6f577f:/# apt install openjdk-8-jre jruby root@9adf8e6f577f:/# jgem install bundler /usr/lib/ruby/vendor_ruby/psych.rb:6: warning: already initialized constant SNAKEYAML_VERSION /usr/lib/ruby/vendor_ruby/psych.rb:6: warning: already initialized constant ANY /usr/lib/ruby/vendor_ruby/psych.rb:6: warning: already initialized constant UTF8 /usr/lib/ruby/vendor_ruby/psych.rb:6: warning: already initialized constant UTF16LE /usr/lib/ruby/vendor_ruby/psych.rb:6: warning: already initialized constant UTF16BE /usr/share/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:59:in `require': It seems your ruby installation is missing psych (for YAML output). To eliminate this warning, please install libyaml and reinstall your ruby. LoadError: load error: psych -- java.lang.NoClassDefFoundError: Could not initialize class org.jruby.ext.psych.PsychEmitter require at org/jruby/RubyKernel.java:955 require at /usr/share/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:59 <main> at /usr/share/jruby/lib/ruby/stdlib/yaml.rb:6 require at org/jruby/RubyKernel.java:955 require at /usr/share/jruby/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:59 (root) at /usr/share/jruby/lib/ruby/stdlib/rubygems.rb:1 load_yaml at /usr/share/jruby/lib/ruby/stdlib/rubygems.rb:716 load_file at /usr/share/jruby/lib/ruby/stdlib/rubygems/config_file.rb:349 initialize at /usr/share/jruby/lib/ruby/stdlib/rubygems/config_file.rb:202 do_configuration at /usr/share/jruby/lib/ruby/stdlib/rubygems/gem_runner.rb:79 <main> at /usr/bin/jgem:21 The problem doesn't seem to depend on the package being installed. I tried trollop, bundler and a local gem and got the same error for all. At least the following yaml-related packages were installed as dependencies: ruby-psych/bionic,now 2.2.4-6build4 amd64 [installed,automatic] libyaml-snake-java/bionic,now 1.20-1 all [installed,automatic] libyaml-0-2/bionic,now 0.1.7-2ubuntu3 amd64 [installed,automatic] root@9adf8e6f577f:/# apt-cache policy jruby jruby: Installed: 9.1.13.0-1 Candidate: 9.1.13.0-1 Version table: *** 9.1.13.0-1 500 500 http://archive.ubuntu.com/ubuntu bionic/universe amd64 Packages 100 /var/lib/dpkg/status ** Affects: jruby (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1816540 Title: jgem is unusable To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/jruby/+bug/1816540/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs