异常：java.lang.ClassCastException: org.apache.catalina.util.DefaultAnnotationProcessor
解决：删除work下的临时文件
java.lang.LinkageError: loader constraints violated when linking javax/el/ExpressionFactory class
解决：错误的原因是tomcat/lib下的el-api.jar与项目WEB-INF/lib目录下的el-api.jar冲突，把项目目录下的el-api.jar删除即可

异常：java.lang.ClassNotFoundException: org.jbpm.web.JobExecutorLauncher
解决：Upgrading jBPM from 3.1.2 to 3.2.3

异常：Caused by: java.lang.UnsupportedClassVersionError: Bad version number in .class file
解决：将eclipse的编译器版本修改下