org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is

org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is java.lang.NoClassDefFoundError: Could not initialize class sun.awt.X11.XToolkit

at org.springframework.web.servlet.DispatcherServlet.triggerAfterCompletionWithError(DispatcherServlet.java:1259)

at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)

at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:953)

at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:855)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)

at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:829)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)

at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)

at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)

linux环境下，图片上传偶尔会出现这种异常，

原因：（个人理解）在处理一些图片的时候，像图片上传等，需要运行一个X-server以便能使用awt来进行处理，应该是代码的解析和图形的处理是分开的。

处理方式：tomcat中bin目录下catalina.sh文件中，增加 JAVA_OPTS="-Djava.awt.headless=true"
默认有这个参数，不用管它（本身已经加了#，注释了） 加完直接重启就行了。