View the original community article here
Last tested: Dec 3, 2020
This is an extreme edge case where this occurred because a user was running the first Java11 stable build ever from 2018 (documentation). Basically when first starting up Looker we try to figure out what version of java you are running, and we do that by parsing the individual pieces of 11.X.XX_XXX. We assume it'll take that form since all (or almost all) other builds besides the very first one from 2018 are like that, and that assumption is being broken here in a way Looker can't handle.
To resolve this error if you come upon it, you should update your Java version to Java11 latest.
Full error message:
[looker@looker looker]$ ./looker start
NoMethodError: undefined method `split' for nil:NilClass
initialize at uri:classloader:/helltool-component-build/lib/helltool/java_version.class:31
<module:Looker> at uri:classloader:/helltool-component-build/lib/looker.class:401
<main> at uri:classloader:/helltool-component-build/lib/looker.class:5
load at org/jruby/RubyKernel.java:1009
<main> at uri:classloader:/helltool-component-build/lib/looker.rb:1
require at org/jruby/RubyKernel.java:974
require at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:54
<main> at uri:classloader:/helltool-component-build/lib/helltool/cli.class:1
load at org/jruby/RubyKernel.java:1009
<main> at uri:classloader:/helltool-component-build/lib/helltool/cli.rb:1
require at org/jruby/RubyKernel.java:974
require at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:54
<main> at uri:classloader:/helltool-component-build/bin/helltool:30
load at org/jruby/RubyKernel.java:1009
<main> at uri:classloader:/META-INF/main.rb:1
require at org/jruby/RubyKernel.java:974
require at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:54
<main> at <script>:3
ERROR: org.jruby.embed.EvalFailedException: (NoMethodError) undefined method `split' for nil:NilClass
This content is subject to limited support.