java.lang.NoClassDefFoundError: org/activiti/bpmn/model/StartEvent

1、错误描述

java.lang.NoClassDefFoundError: org/activiti/bpmn/model/StartEvent
	at org.activiti.image.impl.DefaultProcessDiagramGenerator.<init>(DefaultProcessDiagramGenerator.java:90)
	at org.activiti.image.impl.DefaultProcessDiagramGenerator.<init>(DefaultProcessDiagramGenerator.java:83)
	at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.initProcessDiagramGenerator(ProcessEngineConfigurationImpl.java:1107)
	at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.init(ProcessEngineConfigurationImpl.java:421)
	at org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl.buildProcessEngine(ProcessEngineConfigurationImpl.java:412)
	at org.activiti.engine.impl.test.TestHelper.getProcessEngine(TestHelper.java:227)
	at org.activiti.engine.test.ActivitiRule.initializeProcessEngine(ActivitiRule.java:237)
	at org.activiti.engine.test.ActivitiRule.starting(ActivitiRule.java:205)
	at org.activiti.engine.test.ActivitiRule.startingQuietly(ActivitiRule.java:171)
	at org.activiti.engine.test.ActivitiRule.access$000(ActivitiRule.java:86)
	at org.activiti.engine.test.ActivitiRule$1.evaluate(ActivitiRule.java:124)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

java.lang.NullPointerException
	at org.activiti.designer.test.ProcessTestAudition.startProcess(ProcessTestAudition.java:26)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.activiti.engine.test.ActivitiRule$1.evaluate(ActivitiRule.java:126)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

org.activiti.engine.ActivitiException: Programmatic error: could not instantiate org.activiti.designer.test.ProcessTestAudition
	at org.activiti.engine.test.ActivitiRule.finished(ActivitiRule.java:268)
	at org.activiti.engine.test.ActivitiRule.finishedQuietly(ActivitiRule.java:179)
	at org.activiti.engine.test.ActivitiRule.access$400(ActivitiRule.java:86)
	at org.activiti.engine.test.ActivitiRule$1.evaluate(ActivitiRule.java:135)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.ClassNotFoundException: org/activiti/designer/test/ProcessTestAudition
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:259)
	at org.activiti.engine.test.ActivitiRule.finished(ActivitiRule.java:265)
	... 19 more

2、错误原因

     由错误提示可知，是缺少activiti-bpmn-model有关的jar

3、解决办法

（1）将activiti-bpmn-model-5.21.0.jar复制到lib目录下

（2）在pom.xml中添加

<!-- https://mvnrepository.com/artifact/org.activiti/activiti-engine -->
<dependency>
    <groupId>org.activiti</groupId>
    <artifactId>activiti-engine</artifactId>
    <version>5.21.0</version>
</dependency>