private ProcessEngine processEngine;
    private RuntimeService runtimeService;
    private TaskService taskService;

    private void getProcessEngine( boolean historyOn, String jdbc ) {
        ProcessEngineConfiguration configuration = ProcessEngineConfiguration
            .createStandaloneProcessEngineConfiguration()
            .setDatabaseSchemaUpdate(
                    ProcessEngineConfiguration.DB_SCHEMA_UPDATE_CREATE_DROP )
            .setJdbcUrl( jdbc ).setJdbcMaxActiveConnections( 1000 );
        if( "postgresql".equalsIgnoreCase( jdbc.split( ":" )[1])) {
            configuration.setJdbcUsername( "postgres" ).setJdbcPassword( "mypass" );
        }

        if( historyOn ) {
            configuration.setHistory( ProcessEngineConfiguration.HISTORY_FULL );
        } else {
            configuration.setHistory( ProcessEngineConfiguration.HISTORY_NONE );
        }
        processEngine = configuration.buildProcessEngine();
    }

    @Override
    public void init( File schema, boolean historyOn, String jdbc )
            throws Exception {
        getProcessEngine( historyOn, jdbc );
        BpmnModelInstance modelInstance = Bpmn.readModelFromFile( schema );
        RepositoryService repositoryService = processEngine
            .getRepositoryService();
        List< ProcessDefinition > processDefinitions = repositoryService
            .createProcessDefinitionQuery().list();
        if( processDefinitions.isEmpty() ) {
            repositoryService.createDeployment()
                .addModelInstance( "test_PT.bpmn", modelInstance ).deploy();
        }
        runtimeService = processEngine.getRuntimeService();
        taskService = processEngine.getTaskService();
        class ExitHook extends Thread {

            public void run() {
                processEngine.close();
            }
        }
        Runtime.getRuntime().addShutdownHook( new ExitHook() );
    }

//This method is called by each thread in a loop and then sleeps for a second.
    @Override
    public String startProcessOrFinishCurrentTask( String procID )
            throws Exception {
        List< Task > list = taskService.createTaskQuery().active()
            .processInstanceId( procID ).list();
        if( list.isEmpty() ) {
            return createProcessInstance().getId();
        } else {
            list.stream().forEach( c -> {
                if( c.getName().equals( "Stage3" ) ) {
                    taskService.setVariable( c.getId(), "var1",
                            flowSelector() );
                }
                taskService.complete( c.getId() );
            } );
            return procID;
        }
    }

    private ProcessInstance createProcessInstance() {
        return runtimeService.startProcessInstanceByKey( "test_process" );
    }