javax.servlet.ServletException：java.lang.NoClassDefFoundError：org / apache / commons / io / output / DeferredFileOutputStream

Question

I am trying to upload a file using JSP and I got the error as org.apache.jasper.JasperException: An exception occurred processing JSP page /upload.jsp at line 31

28:       upload.setSizeMax( maxFileSize );   
29:       try{   
30:          // Parse the request to get file items.  
31:          List fileItems = upload.parseRequest(request);  
32:   
33:          // Process the uploaded file items  
34:          Iterator i = fileItems.iterator();    

exception that I got is:

javax.servlet.ServletException: java.lang.NoClassDefFoundError:    org/apache/commons/io/output/DeferredFileOutputStream  
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:912)  
    org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:841)  
    org.apache.jsp.upload_jsp._jspService(upload_jsp.java:154)  

Answer 1

java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream

This means that the mentioned class is missing in webapp's runtime classpath. As the package name hints, it's part of Apache Commons IO . You need to download the zip file containing the binary JARs, extract it and then drop commons-io.jar in your webapp's /WEB-INF/lib folder, along with the commons-fileupload.jar which you should already have there.

Do not put it in Tomcat's /lib while having the commons-fileupload.jar in webapp's /WEB-INF/lib . Do not fiddle around in project's Build Path setting. Just drop the two JARs in webapp's /WEB-INF/lib and you should be all set.

See also:

• How to upload files to server using JSP/Servlet?

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Unrelated to the concrete problem, Java code doesn't belong in JSP files. It belongs in Java classes. It's time to learn how to create and use servlets before it's too late.