title: JSP compilation issue due to JSTL validation on adding a jsp to running embedded jetty instance
body: <p>I have created a JSP test framework but running into this issue if I try to add jsp to running server. The project config is as follows:</p>
  
  <ol>
  <li>JSP is present under /webapps folder. </li>
  <li>I create a ServletHolder dispatching to this JSP and add the servlet to webcontext. </li>
  <li>I setup the embedded Jetty server with this webcontext and start the server  </li>
  <li>jsp page is served fine.</li>
  </ol>
  
  <p>Now I create another ServletHolder for a different JSP and add it to running server's webcontext.
  On accessing the page, I get following exception</p>
  
  <pre><code>java.lang.NullPointerException
  at org.apache.taglibs.standard.tlv.JstlBaseTLV.validate(JstlBaseTLV.java:149)
  at org.apache.taglibs.standard.tlv.JstlCoreTLV.validate(JstlCoreTLV.java:105)
  at org.apache.jasper.compiler.TagLibraryInfoImpl.validate(TagLibraryInfoImpl.java:949)
  at org.apache.jasper.compiler.Validator.validateXmlView(Validator.java:1921)
  at org.apache.jasper.compiler.Validator.validate(Validator.java:1888)
  at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:223)
  at org.apache.jasper.compiler.Compiler.compile(Compiler.java:451)
  at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:625)
  at org.apache.jasper.servlet.JspServletWrapper.loadTagFile(JspServletWrapper.java:280)
  at org.apache.jasper.compiler.TagFileProcessor.loadTagFile(TagFileProcessor.java:660)
  at org.apache.jasper.compiler.TagFileProcessor.access$000(TagFileProcessor.java:91)
  at  org.apache.jasper.compiler.TagFileProcessor$TagFileLoaderVisitor.visit(TagFileProcessor.java:719)
  
  org.apache.jasper.JasperException: PWC6033: Error in Javac compilation for JSP
  at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:634)
  </code></pre>
  
  <p>Strange thing is, if I stop the webcontext and add the servlet and start webcontext again, things run fine. </p>
  
  <p>I tried to debug this and found that for the second jsp/tag call to 'JstlCoreTLV.getInitParameters()' is returning null, maybe jstl is reusing the validation object from previous cache and this property is reset to null in between.</p>
  
  <p>Has anyone come across this issue? would it be a bug in JSTL library? </p>