title: Unable to instantiate service for Class 'org.drools.builder.KnowledgeBuilderFactoryService'
body: <p>I updated from Drools 5.5.0 to Drools 6.1.0. </p>
  
  <p>And when I execute my code, I have this problem. </p>
  
  <pre><code>java.lang.IllegalArgumentException: Unable to instantiate service for Class 'org.drools.builder.KnowledgeBuilderFactoryService'
      at org.drools.util.ServiceRegistryImpl.get(ServiceRegistryImpl.java:166)
      at org.drools.builder.KnowledgeBuilderFactory.loadServiceFactory(KnowledgeBuilderFactory.java:130)
      at org.drools.builder.KnowledgeBuilderFactory.getKnowledgeBuilderServiceFactory(KnowledgeBuilderFactory.java:124)
      at org.drools.builder.KnowledgeBuilderFactory.newKnowledgeBuilder(KnowledgeBuilderFactory.java:46)
      at com.drools.optimizer.AppExpertSystem.readKnowledgeBase(AppExpertSystem.java:133)
      at com.drools.optimizer.AppExpertSystem.loadKnowledgeBase(AppExpertSystem.java:119)
      at com.drools.optimizer.AppExpertSystem.&lt;init&gt;(AppExpertSystem.java:56)
      at eventlauncher.OptimizerLauncher.NuevoEscenario(OptimizerLauncher.java:57)
      at eventlauncher.DemoPruebas.main(DemoPruebas.java:18)
  Caused by: java.lang.IllegalArgumentException: Unable to instantiate 'org.drools.builder.impl.KnowledgeBuilderFactoryServiceImpl'
      at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.newInstance(ServiceRegistryImpl.java:217)
      at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.call(ServiceRegistryImpl.java:209)
      at org.drools.util.ServiceRegistryImpl.get(ServiceRegistryImpl.java:164)
      ... 8 more
  Caused by: java.lang.ClassNotFoundException: org.drools.builder.impl.KnowledgeBuilderFactoryServiceImpl
      at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:169)
      at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.newInstance(ServiceRegistryImpl.java:214)
      ... 10 more
  Exception in thread "main" java.lang.RuntimeException: java.lang.IllegalArgumentException: Unable to instantiate service for Class 'org.drools.builder.KnowledgeBuilderFactoryService'
      at com.drools.optimizer.AppExpertSystem.loadKnowledgeBase(AppExpertSystem.java:126)
      at com.drools.optimizer.AppExpertSystem.&lt;init&gt;(AppExpertSystem.java:56)
      at eventlauncher.OptimizerLauncher.NuevoEscenario(OptimizerLauncher.java:57)
      at eventlauncher.DemoPruebas.main(DemoPruebas.java:18)
  Caused by: java.lang.IllegalArgumentException: Unable to instantiate service for Class 'org.drools.builder.KnowledgeBuilderFactoryService'
      at org.drools.util.ServiceRegistryImpl.get(ServiceRegistryImpl.java:166)
      at org.drools.builder.KnowledgeBuilderFactory.loadServiceFactory(KnowledgeBuilderFactory.java:130)
      at org.drools.builder.KnowledgeBuilderFactory.getKnowledgeBuilderServiceFactory(KnowledgeBuilderFactory.java:124)
      at org.drools.builder.KnowledgeBuilderFactory.newKnowledgeBuilder(KnowledgeBuilderFactory.java:46)
      at com.drools.optimizer.AppExpertSystem.readKnowledgeBase(AppExpertSystem.java:133)
      at com.drools.optimizer.AppExpertSystem.loadKnowledgeBase(AppExpertSystem.java:119)
      ... 3 more
  Caused by: java.lang.IllegalArgumentException: Unable to instantiate 'org.drools.builder.impl.KnowledgeBuilderFactoryServiceImpl'
      at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.newInstance(ServiceRegistryImpl.java:217)
      at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.call(ServiceRegistryImpl.java:209)
      at org.drools.util.ServiceRegistryImpl.get(ServiceRegistryImpl.java:164)
      ... 8 more
  Caused by: java.lang.ClassNotFoundException: org.drools.builder.impl.KnowledgeBuilderFactoryServiceImpl
      at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:169)
      at org.drools.util.ServiceRegistryImpl$ReflectionInstantiator.newInstance(ServiceRegistryImpl.java:214)
      ... 10 more
  </code></pre>
  
  <p>The line 133 in which is the error is the bold line in the next method:</p>
  
  <pre><code>private static KnowledgeBase readKnowledgeBase() throws Exception {
  
          **KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();**
  
          kbuilder.add(ResourceFactory.newClassPathResource(CTES.RULES),
                  ResourceType.DRL);
  
          KnowledgeBuilderErrors errors = kbuilder.getErrors();
  
          if (errors.size() &gt; 0) {
              for (KnowledgeBuilderError error : errors) {
                  System.err.println(error);
              }
              throw new IllegalArgumentException("Could not parse knowledge.");
          }
          KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
          kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
          KnowledgeBaseConfiguration config = KnowledgeBaseFactory.newKnowledgeBaseConfiguration();
          config.setOption(EventProcessingOption.STREAM );
  
          return kbase;
      }
  </code></pre>
  
  <p>I don't have change any line of my code, and I don't understand what it is happening :(</p>
  
  <p>Anybody can help me?</p>
  
  <p>Best regards!</p>