Error trying to get Activiti 6 UI up using the original released war

[kausdi]

I am trying to get the acitiviti 6 UI up. I downloaded the war from https://github.com/Activiti/Activiti/releases/tag/activiti-6.0.0.

When trying to deploy the activiti-app war or the activiti-rest war (Tomcat 9, Java 8). I get the following error: 

java.util.ServiceConfigurationError: org.activiti.engine.cfg.ProcessEngineConfigurator: Provider org.activiti.management.jmx.JMXConfigurator not a subtype

        at java.util.ServiceLoader.fail(ServiceLoader.java:239)

        at java.util.ServiceLoader.access$300(ServiceLoader.java:185)

        at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:376)

        at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404)

        at java.util.ServiceLoader$1.next(ServiceLoader.java:480)

        at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.initConfigurators(ProcessEngineConfigurationImpl.java:1377)

        at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.init(ProcessEngineConfigurationImpl.java:682)

        at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.buildProcessEngine(ProcessEngineConfigurationImpl.java:664)

        at org.activiti.spring.SpringProcessEngineConfiguration.buildProcessEngine(SpringProcessEngineConfiguration.java:65)

        at org.activiti.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:57)

        at org.activiti.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:32)

        at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:168)

I tried to checkout the 6.x branch and build the war and deploy, same error.

Don't know why I am getting this. I am getting it here: 

ServiceLoader<ProcessEngineConfigurator> configuratorServiceLoader
      = ServiceLoader.load(ProcessEngineConfigurator.class, classLoader);
int nrOfServiceLoadedConfigurators = 0;
for (ProcessEngineConfigurator configurator : configuratorServiceLoader) { //on this line
   allConfigurators.add(configurator);
   nrOfServiceLoadedConfigurators++;
}

clearly configuratorServiceLoader is created by scanning all of ProcessEngineerConfigurator still the 'org.activiti.management.jmx.JMXConfigurator not a subtype' error comes. The 

JMXConfigurator extends AbstractProcessEngineConfigurator

 as well.

I tried the following when the processEngineConfiguration bean is created so that the above statements are not executed at all.

processEngineConfiguration.setEnableConfiguratorServiceLoader(false);

Post this I started getting another error:

Caused by: liquibase.exception.ChangeLogParseException: Error Reading Migration File: Found 3 files that match org/activiti/form/db/liquibase/activiti-form-db-changelog.xml

        at liquibase.parser.core.xml.XMLChangeLogSAXParser.parseToNode(XMLChangeLogSAXParser.java:112)

        at liquibase.parser.core.xml.AbstractChangeLogParser.parse(AbstractChangeLogParser.java:17)

        at liquibase.Liquibase.getDatabaseChangeLog(Liquibase.java:229)

        at liquibase.Liquibase.update(Liquibase.java:202)

        at liquibase.Liquibase.update(Liquibase.java:192)

        at liquibase.Liquibase.update(Liquibase.java:188)

        at liquibase.Liquibase.update(Liquibase.java:181)

        at org.activiti.form.engine.FormEngineConfiguration.initDbSchema(FormEngineConfiguration.java:575)

        ... 153 common frames omitted

Caused by: java.io.IOException: Found 3 files that match org/activiti/form/db/liquibase/activiti-form-db-changelog.xml

        at liquibase.util.StreamUtil.singleInputStream(StreamUtil.java:205)

        at liquibase.parser.core.xml.XMLChangeLogSAXParser.parseToNode(XMLChangeLogSAXParser.java:93)

Can anyone suggest what am I doing wrong, surely I shouldn't require to change the original code to get it up considered the released war is also giving errors.