In jBPM workflow, next task does not start when the previous task completes

[inoshikag]

My application is running on wildfly server 12.0 and uses jbpm 7.7.0 using CDI.

I can start a workflow process instance successfully and the first task is created.

When the first task completes, the status in `task` table updates successfully.

However, next connected task is not created in `task` table.

Earlier, we used jbpm 6.0.1 and this code worked perfectly.

import javax.annotation.PostConstruct;

import javax.ejb.Startup;

import javax.inject.Inject;

import org.jbpm.services.api.RuntimeDataService;

import org.jbpm.services.api.UserTaskService;

import org.kie.api.runtime.KieSession;

import org.kie.api.runtime.manager.RuntimeEngine;

import org.kie.api.runtime.manager.RuntimeManager;

import org.kie.api.runtime.process.ProcessInstance;

import org.kie.api.task.TaskService;

import org.kie.api.task.model.I18NText;

import org.kie.api.task.model.Task;

import org.kie.api.task.model.TaskData;

import org.kie.internal.runtime.manager.cdi.qualifier.Singleton;

@javax.ejb.Singleton

public class ProcessBean    {

    @Inject

    @Singleton

    private RuntimeManager singletonManager;

    @Inject

    TaskService taskService;

    @PostConstruct

    public void configure() {

        // use toString to make sure CDI initializes the bean

        // this makes sure that RuntimeManager is started asap,

        // otherwise after server restart complete task won't move process forward

        singletonManager.toString();

    }

    public void start(final long taskId, String user) throws Exception{

        if(taskService != null){

            System.out.println("==== starting the task ");  

            taskService.start(taskId, user);

        }

       else{

            System.out.println("======= task service is null");

         }

    }

}

My persistence.xml is attached.

Can someone please help me to figure out the issue?

It would be great even a clue.