Error While Process Instantiation

I am getting below exception while triggering Flowable workflow from spring boot application.

I have a start event (none) which i am instantiating using flowable runtime service by passing the process key and variables as Map<String, object>.
ProcessInstance processInstance = runtimeService.startProcessInstanceByKey(processDefKey, variables) ;

After start event - I have a http task (using to send email), email is working fine using the REST-API (validated), same i have configured in workflow.

After http task - I have user task (associated with boundary timer event).

Start → http task – > user Task (having time event & Task Listener as expression on Create event).

Please suggest what wrong i am doing here.

Exception:
org.flowable.common.engine.api.FlowableException: couldn’t instantiate class org.flowable.engine.impl.bpmn.http.DefaultBpmnHttpActivityDelegate
at org.flowable.common.engine.impl.util.ReflectUtil.instantiate(ReflectUtil.java:139)
at org.flowable.engine.impl.bpmn.helper.AbstractClassDelegate.defaultInstantiateDelegate(AbstractClassDelegate.java:64)
at org.flowable.engine.impl.bpmn.helper.AbstractClassDelegate.defaultInstantiateDelegate(AbstractClassDelegate.java:75)

Full Stack Trace of exception is below for the reference:

org.flowable.common.engine.api.FlowableException: couldn’t instantiate class org.flowable.engine.impl.bpmn.http.DefaultBpmnHttpActivityDelegate
at org.flowable.common.engine.impl.util.ReflectUtil.instantiate(ReflectUtil.java:139)
at org.flowable.engine.impl.bpmn.helper.AbstractClassDelegate.defaultInstantiateDelegate(AbstractClassDelegate.java:64)
at org.flowable.engine.impl.bpmn.helper.AbstractClassDelegate.defaultInstantiateDelegate(AbstractClassDelegate.java:75)
at org.flowable.engine.impl.bpmn.helper.AbstractClassDelegate.instantiateDelegate(AbstractClassDelegate.java:49)
at org.flowable.engine.impl.bpmn.helper.ClassDelegate.getActivityBehaviorInstance(ClassDelegate.java:261)
at org.flowable.engine.impl.bpmn.helper.ClassDelegate.execute(ClassDelegate.java:201)
at org.flowable.engine.impl.agenda.ContinueProcessOperation.executeActivityBehavior(ContinueProcessOperation.java:313)
at org.flowable.engine.impl.agenda.ContinueProcessOperation.executeSynchronous(ContinueProcessOperation.java:170)
at org.flowable.engine.impl.agenda.ContinueProcessOperation.continueThroughFlowNode(ContinueProcessOperation.java:125)
at org.flowable.engine.impl.agenda.ContinueProcessOperation.run(ContinueProcessOperation.java:88)
at org.flowable.common.engine.impl.AbstractEngineConfiguration.lambda$new$0(AbstractEngineConfiguration.java:173)
at org.flowable.engine.impl.interceptor.CommandInvoker.executeOperation(CommandInvoker.java:97)
at org.flowable.engine.impl.interceptor.CommandInvoker.executeOperations(CommandInvoker.java:81)
at org.flowable.engine.impl.interceptor.CommandInvoker.execute(CommandInvoker.java:64)
at org.flowable.engine.impl.interceptor.BpmnOverrideContextInterceptor.execute(BpmnOverrideContextInterceptor.java:26)
at org.flowable.common.engine.impl.interceptor.TransactionContextInterceptor.execute(TransactionContextInterceptor.java:53)
at org.flowable.common.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:83)
at org.flowable.common.spring.SpringTransactionInterceptor.lambda$execute$0(SpringTransactionInterceptor.java:57)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140)
at org.flowable.common.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:57)
at org.flowable.common.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:30)
at org.flowable.common.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:56)
at org.flowable.common.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:51)
at org.flowable.engine.impl.RuntimeServiceImpl.startProcessInstanceByKey(RuntimeServiceImpl.java:121)
at com.boa.flowable.service.ApplicationService.initiateWorkflow(ApplicationService.java:96)
at com.boa.flowable.controllers.ProcessController.createProcessInstance(ProcessController.java:85)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1060)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:962)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.flowable.common.engine.api.FlowableException: Failed to determine FlowableHttpClient
at org.flowable.http.common.impl.HttpClientConfig.determineHttpClient(HttpClientConfig.java:204)
at org.flowable.engine.impl.bpmn.http.DefaultBpmnHttpActivityDelegate.createHttpClient(DefaultBpmnHttpActivityDelegate.java:72)
at org.flowable.http.common.impl.BaseHttpActivityDelegate.(BaseHttpActivityDelegate.java:87)
at org.flowable.engine.impl.bpmn.http.DefaultBpmnHttpActivityDelegate.(DefaultBpmnHttpActivityDelegate.java:66)
at org.flowable.engine.impl.bpmn.http.DefaultBpmnHttpActivityDelegate.(DefaultBpmnHttpActivityDelegate.java:62)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
at java.base/java.lang.Class.newInstance(Class.java:584)
at org.flowable.common.engine.impl.util.ReflectUtil.instantiate(ReflectUtil.java:137)
… 75 more

This error is resolved after adding below dependency in pom.xml.

My Bad. But its resolved now. Thank you.

org.flowable flowable-http 6.1.0