title: Install Logstash error JAVA (OpenJDK 64-Bit Server VM warning)
body: <p>I have followed the official documentation and written the following:</p>
  <pre><code># Update repository
  sudo apt-get update
  
  # Install necessary things. Like SSL support and JDK
  sudo apt-get install apt-transport-https default-jdk -y
  
  # Download and install the GPG KEY. Add the repository for elasticsearch version 7. Update and install logstash
  wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -
  echo &quot;deb https://artifacts.elastic.co/packages/7.x/apt stable main&quot; | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list
  sudo apt-get update &amp;&amp; sudo apt-get install logstash -y
  
  # configure ES daemon
  sudo /bin/systemctl daemon-reload
  sudo /bin/systemctl enable logstash.service
  sudo systemctl start logstash.service
  </code></pre>
  <p>But the following appears:</p>
  <pre><code>OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
  WARNING: An illegal reflective access operation has occurred
  WARNING: Illegal reflective access by com.headius.backport9.modules.Modules to method sun.nio.ch.NativeThread.signal(long)
  WARNING: Please consider reporting this to the maintainers of com.headius.backport9.modules.Modules
  WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
  WARNING: All illegal access operations will be denied in a future release
  /usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/pleaserun-0.0.31/lib/pleaserun/platform/base.rb:112: warning: constant ::Fixnum is deprecated
  Successfully created system startup script for Logstash
  Created symlink /etc/systemd/system/multi-user.target.wants/logstash.service → /etc/systemd/system/logstash.service.
  </code></pre>
  <p>Although it is installed when I run the following command to test it manually:</p>
  <pre><code>/usr/share/logstash/bin/logstash -e &quot;input { stdin { } } output { stdout {} }&quot;
  </code></pre>
  <p>And the error repeats and does not allow to do anything.</p>
  <pre><code>luis@ubuntu18:~$ /usr/share/logstash/bin/logstash -e &quot;input { stdin { } } output { stdout {} }&quot;
  OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
  WARNING: An illegal reflective access operation has occurred
  WARNING: Illegal reflective access by com.headius.backport9.modules.Modules (file:/usr/share/logstash/logstash-core/lib/jars/jruby-complete-9.2.11.1.jar) to method sun.nio.ch.NativeThread.signal(long)
  WARNING: Please consider reporting this to the maintainers of com.headius.backport9.modules.Modules
  WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
  WARNING: All illegal access operations will be denied in a future release
  WARNING: Could not find logstash.yml which is typically located in $LS_HOME/config or /etc/logstash. You can specify the path using --path.settings. Continuing using the defaults
  Could not find log4j2 configuration at path /usr/share/logstash/config/log4j2.properties. Using default config which logs errors to the console
  [FATAL] 2020-07-18 21:49:19.544 [main] runner - An unexpected error occurred! {:error=&gt;#&lt;ArgumentError: Path &quot;/usr/share/logstash/data&quot; must be a writable directory. It is not writable.&gt;, :backtrace=&gt;[&quot;/usr/share/logstash/logstash-core/lib/logstash/settings.rb:528:in `validate'&quot;, &quot;/usr/share/logstash/logstash-core/lib/logstash/settings.rb:288:in `validate_value'&quot;, &quot;/usr/share/logstash/logstash-core/lib/logstash/settings.rb:199:in `block in validate_all'&quot;, &quot;org/jruby/RubyHash.java:1415:in `each'&quot;, &quot;/usr/share/logstash/logstash-core/lib/logstash/settings.rb:198:in `validate_all'&quot;, &quot;/usr/share/logstash/logstash-core/lib/logstash/runner.rb:310:in `execute'&quot;, &quot;/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/clamp-0.6.5/lib/clamp/command.rb:67:in `run'&quot;, &quot;/usr/share/logstash/logstash-core/lib/logstash/runner.rb:268:in `run'&quot;, &quot;/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/clamp-0.6.5/lib/clamp/command.rb:132:in `run'&quot;, &quot;/usr/share/logstash/lib/bootstrap/environment.rb:88:in `&lt;main&gt;'&quot;]}
  [ERROR] 2020-07-18 21:49:19.633 [main] Logstash - java.lang.IllegalStateException: Logstash stopped processing because of an error: (SystemExit) exit
  </code></pre>
  <p>I don't know if it's because of the java version (openjdk 11.0.7 2020-04-14) or another error. I have never used java so these errors confuse me a bit. Thank you all.</p>