clean时：
Removing obsolete files from server...
Could not clean server of obsolete files: null
java.lang.NullPointerException
运行时：
七月 26, 2017 12:02:26 上午 org.apache.catalina.startup.Catalina load 信息: Initialization processed in 925 ms 七月 26, 2017 12:02:26 上午 org.apache.catalina.startup.Catalina start 严重: The required Server component failed to start so Tomcat is unable to start. org.apache.catalina.LifecycleException: Failed to start component [StandardServer[-1]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) at org.apache.catalina.startup.Catalina.start(Catalina.java:625) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:351) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:485) Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:769) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 7 more Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:439) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 9 more Caused by: org.apache.catalina.LifecycleException: A child container failed during start at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:925) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 11 more
主要是因为 1.此tomcat不支持修改host的name属性，必须修改为原属性
2.修改之后需要右键STS-tomcat，找到browse Devlopment选项，进而找到tomcat的conf/server.xml，修改成与项目视图中的server.xml一样内存
如果都不行，删除tomcat，删除G:\sts\workspacemy\.metadata\.plugins\org.eclipse.wst.server.core\路径下除publish.xml外的文件（或都删了，未试）
，再重新安装
另此路径也关键：G:\sts\workspacemy\.metadata\.plugins\org.eclipse.wst.server.core
原文：http://www.cnblogs.com/xianlai-huang/p/7237215.html