debug travis jvm picker vs commands in before_install hook

.travis.yml

@@ -1,18 +1,12 @@
 os:
   - linux
-  - osx
 
 rvm:
-  - 1.9.3
   - jruby-9.1.9.0
-  - rbx-3
-  - 2.0.0
-  - 2.1
-  - 2.2
-  - 2.3
-  - 2.4
   - 2.5
-  - ruby-head
+
+jdk:
+  - openjdk8
 
 sudo: false
 
@@ -24,6 +18,9 @@ before_install:
   - ruby -e "system('gem update --system') if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.3')"
   - gem install bundler --version '~> 1.17'
 
+before_script:
+  - 'export JAVA_OPTS="${JAVA_OPTS_FOR_SPECS}"'
+
 env:
   global:
   matrix:
@@ -39,7 +36,7 @@ matrix:
   include:
   - rvm: jruby-9.2.5.0
     jvm: openjdk11
-    env: "JAVA_OPTS='--add-opens java.base/java.io=org.jruby.dist --add-opens java.base/sun.nio.ch=org.jruby.dist'"
+    env: "JAVA_OPTS_FOR_SPECS='--add-opens java.base/java.io=org.jruby.dist --add-opens java.base/sun.nio.ch=org.jruby.dist'"
   exclude:
     # Travis does not provide 1.9.3 on OSX
   - rvm: 1.9.3