Issue
When I try to run my webapp on Tomcat 7, I got the following exception:
exception
javax.servlet.ServletException: java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.servlet.jsp.JspApplicationContext.getExpressionFactory()Ljavax/el/ExpressionFactory;
" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspApplicationContext,
have different Class objects for the type javax/el/ExpressionFactory used in the signature
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:343)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
root cause
java.lang.LinkageError: loader constraint violation: when resolving interface method "javax.servlet.jsp.JspApplicationContext.getExpressionFactory()Ljavax/el/ExpressionFactory;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/index_jsp, and the class loader (instance of org/apache/catalina/loader/StandardClassLoader) for resolved class, javax/servlet/jsp/JspApplicationContext, have different Class objects for the type javax/el/ExpressionFactory used in the signature
org.apache.jsp.index_jsp._jspInit(index_jsp.java:31)
org.apache.jasper.runtime.HttpJspBase.init(HttpJspBase.java:49)
org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:180)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
It seems that there's a conflict between two .jar
librairies, but I don't know which they are. How can I figure them out and solve it?
Solution
That will happen when you include server-specific libraries of a different server make/version in the /WEB-INF/lib
of your web application, such as jsp-api.jar
, el-api.jar
, servlet-api.jar
, etc. You need to remove them all. The /WEB-INF/lib
should not contain any server-specific libraries. They belongs in the specific server itself (Tomcat has them in its /lib
folder already).
This is by the way a pretty common beginner's mistake whenever they encounter compilation errors on the JSP/Servlet API in their IDE project. This should have been solved differently, namely by integrating the server in the IDE and adding the server as "Target runtime" to the project.
See also:
Answered By - BalusC