title: Migration to JDK 11 has error occure "java.lang.NoClassDefFoundError: javax/activation/DataSource" (tomcat 9.0.12)
body: <p>I'm migrating java project use JDK8 to use JDK 11 then has error occurred relate of javax activation.
  Following migration guide from Oracle, <a href="https://docs.oracle.com/en/java/javase/11/migrate/index.html#JSMIG-GUID-561005C1-12BB-455C-AD41-00455CAD23A6" rel="noreferrer">I see java.activation that module was removed from JDK 11.</a></p>
  
  <p>After that, I give a suggest to added third parties **activation-1.0.2.jar* but still, an error has occurred? 
  Please give a suggestion about problem ? and could you tell me about experience of Migration source code use Java 8 to Java 11 (server with tomcat 9.0.12. compiler by Eclipse 2018-09(4.9.0)</p>
  
  <p>This is detail error : </p>
  
  <pre><code>Caused by: java.lang.NoClassDefFoundError: javax/activation/DataSource
      at java.base/java.lang.Class.getDeclaredMethods0(Native Method)
      at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3167)
      at java.base/java.lang.Class.getDeclaredMethods(Class.java:2310)
      at org.apache.catalina.util.Introspection.getDeclaredMethods(Introspection.java:133)
      at org.apache.catalina.startup.WebAnnotationSet.loadMethodsAnnotation(WebAnnotationSet.java:285)
      at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:138)
      at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:69)
      at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:328)
      at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:768)
      at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299)
      at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
      at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5007)
      at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
  </code></pre>