StevenXu的专栏

No grammar constraints (DTD or XML Schema) referenced in the document. 在web.xml头部信息中，添加以下内容即可解决问题 http://www.w3.org/2002/xmlspec/dtd/2.10/xmlspec.dtd">

cvc-complex-type.2.4.a: Invalid content was found starting with element 'async-supported'. One of   '{"http://java.sun.com/xml/ns/javaee":init-param}' is expected. web.xml总是报cvc-complex-type.2

java.lang.NullPointerException at org.apache.jsp.index_jsp._jspInit 启动tomcat时，报：java.lang.NullPointerException at org.apache.jsp.**_jsp.jspInit(index_jsp.java)异常 写了一个空的JSP页面依旧还是报错，在网上查了下，是由于ja