jbpm create process using Fluent API？

Question

According to JBPM's user guide about Fluent API, I try to create a process using Fluent API of drools' 7.62.0 version, and follows is my example code:

public static void testFluentCreateBPMN2() {
        String processId = "process1";
        ProcessBuilderFactory factory = ProcessBuilderFactories.get();
        // Create process builder
        Process process = factory.processBuilder(processId)
                // package and name
                .packageName("org.jbpm")
                .name("My process")
                // start node
                .startNode(1).name("Start").done()
                // Add variable of type string
                .variable(Variable.var("pepe", String.class))
                // Add exception handler
                .exceptionHandler(IllegalArgumentException.class, Dialect.JAVA, "System.out.println(\"Exception\");")
                // script node in Java language that prints "action"
                .actionNode(2).name("Action")
                .action(Dialect.JAVA,
                        "System.out.println(\"Action\");").done()
                // end node
                .endNode(3).name("End").done()
                // connections
                .connection(1, 2)
                .connection(2, 3)
                .build();
        KieHelper kieHelper = new KieHelper();

        KieSession kieSession = kieHelper.build().newKieSession();
        Map<String, Object> maps = new HashMap<>();
        maps.put("pepe", "Hello World");
        kieSession.startProcess(processId, maps);
    }

when I try to execute this code, a error occurs which execute ProcessBuilderFactories.get() follows:

Exception in thread "main" java.lang.NullPointerException
    at org.jbpm.process.core.impl.XmlProcessDumperFactory.newXmlProcessDumperFactory(XmlProcessDumperFactory.java:24)
    at org.jbpm.ruleflow.core.RuleFlowProcessFactoryBuilder.<init>(RuleFlowProcessFactoryBuilder.java:26)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:442)
    at org.kie.api.fluent.ProcessBuilderFactories.get(ProcessBuilderFactories.java:38)
    at org.example.App.testFluentCreateBPMN2(App.java:28)
    at org.example.App.main(App.java:23)

I feel very puzzled about this problem. And do you can give me it's solution or some advice? Thank you very much.

Answer 1

Are you including in your code the dependency to jbpm-bpmn2 or any other implementation of the interface XmlProcessDumperFactoryService?

jbpm-bpmn2 has this one:

public class XmlProcessDumperFactoryServiceImpl implements XmlProcessDumperFactoryService {

public XmlProcessDumper newXmlProcessDumper() {
    return XmlBPMNProcessDumper.INSTANCE;
}

}