Bug 51544 - EL parser problem for EmptyList
Summary: EL parser problem for EmptyList
Alias: None
Product: Tomcat 7
Classification: Unclassified
Component: Jasper (show other bugs)
Version: 7.0.19
Hardware: PC Linux
: P2 normal (vote)
Target Milestone: ---
Assignee: Tomcat Developers Mailing List
Depends on:
Reported: 2011-07-23 08:17 UTC by bozho
Modified: 2011-07-25 16:23 UTC (History)
0 users

A copy of two files from gump output, 25 Jul 2011 08:58:47 (UTC) (20.63 KB, text/plain)
2011-07-25 10:31 UTC, Konstantin Kolinko

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Description bozho 2011-07-23 08:17:58 UTC
When I return Collections.emptyList() and then use ${list.isEmpty()} in a JSP, a problem occurs (see below). It didn't occur in older Tomcat 7 versions (like 7.0.5).

15:             ${user.names}<br />
16:         </div>
17:     </c:forEach>
18:     <c:if test="${users.isEmpty()}">
19:         <div>${msg.noResults}</div>
20:     </c:if>
21: </div>

Stacktrace:] with root cause
java.lang.IllegalAccessException: Class javax.el.BeanELResolver can not access a member of class java.util.Collections$EmptyList with modifiers "public"
	at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:95)
	at java.lang.reflect.Method.invoke(Method.java:607)
	at javax.el.BeanELResolver.invoke(BeanELResolver.java:467)
	at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:161)
	at org.apache.el.parser.AstValue.getValue(AstValue.java:159)
	at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
	at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:985)
	at org.apache.jsp.WEB_002dINF.jsp.externalUsers_jsp._jspx_meth_c_005fif_005f2(externalUsers_jsp.java:2060)
	at org.apache.jsp.WEB_002dINF.jsp.externalUsers_jsp._jspService(externalUsers_jsp.java:396)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:433)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:471)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
	at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
	at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
	at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1120)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:890)
Comment 1 Mark Thomas 2011-07-24 11:14:51 UTC
I have added unit tests for this in Tomcat 7 that access the list in EL as a property of a bean, in EL directly and from within a JSP and all pass.

At this points it looks an application issue.

If you still see this problem with the latest Tomcat 7 release then to re-open this issue you'll need to provide the simplest possible JSP that demonstrates this issue.
Comment 2 Konstantin Kolinko 2011-07-25 09:30:50 UTC
Gump caught this error with the tests that Mark wrote for this issue.

Testsuite: org.apache.el.TestValueExpressionImpl
Tests run: 7, Failures: 0, Errors: 2, Time elapsed: 0.131 sec
- testBug51544Bean
- testBug51544Direct

Testsuite: org.apache.el.TestELInJsp
Tests run: 14, Failures: 0, Errors: 1, Time elapsed: 23.259 sec
- testBug51544
Comment 3 Konstantin Kolinko 2011-07-25 10:31:29 UTC
Created attachment 27311 [details]
A copy of two files from gump output, 25 Jul 2011 08:58:47 (UTC)

1. I am attaching a copy from the logs produced by gump run

The log files are


2. I am not able to reproduce this in my environment (Sun JDK 6u26 32-bit, WinXP): tested with BIO connector, like gump did. All tests run fine.

bozho, what version of java runtime are you using?
Comment 4 Mark Thomas 2011-07-25 10:36:51 UTC
Gump is running open JDK:

java version "1.6.0_20" OpenJDK Runtime Environment (IcedTea6 1.9.8) (6b20-1.9.8-0ubuntu1~10.04.1) OpenJDK 64-Bit Server VM (build 19.0-b09, mixed mode)
Comment 5 bozho 2011-07-25 10:44:31 UTC

My version is:

java version "1.6.0_20"
OpenJDK Runtime Environment (IcedTea6 1.9.1) (amazon-
OpenJDK Client VM (build 19.0-b06, mixed mode)
Comment 6 bozho 2011-07-25 10:46:04 UTC
it's still in testing mode, hence the -client VM. I will change to -server, but I guess it will still be there.
Comment 7 Mark Thomas 2011-07-25 14:05:50 UTC
I took a look at the Oracle and OpenJDK implementations of emptyList(). If I modify the test to use size() rather than isEmpty() it fails on the Oracle JDK as well.
Comment 8 Mark Thomas 2011-07-25 16:23:38 UTC
Fixed in 7.0.x and will be included in 7.0.20 onwards.