[TILES-598] Possible NullPointerException in OptionsRenderer

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.5
• Fix Version/s: 3.1.x, 3.0.7
• Component/s: tiles-extras
• Flags: Patch
• Assignee: Unassigned
• Reporter: Jo Schm
• Created: 05/Jul/18 13:48
• Updated: 07/Sep/18 11:31
• Resolved: 07/Sep/18 11:31

Description

Analysis:

OptionsRenderer#attemptTemplate (line 193)

If Map#containsKey(template) is true for a template there is another call to Map#get(template) to retrieve the value for that template / key. At that point the observation (there exists a mapping) might have become invalid because the Entry could have been expired at the second call. In this case Map#get(template) returns "null" which causes a NPE when unboxing is performed.

Reproduce:

Set Cache TTL to 5 seconds: 

-Dorg.apache.tiles.extras.renderer.OptionsRenderer.cache_ttl_ms=50000

Set two breakpoints:

BP 1) line 2728, LocaleCache$Segment#containsKey(Object, int)

BP 2) line 2065, LocaleCache$Segment#get(Object, int)

Call an URL to trigger page rendering. You should hit BP 1) with a key e.g. "header.jsp". Wait 5 seconds, disable BP 1) and resume. You should hit BP 2) now. See how #get(..) returns "null" for that key ("header.jsp").

 

Example Stacktrace:

java.lang.NullPointerException: null
at org.apache.tiles.extras.renderer.OptionsRenderer$Cache.attemptTemplate(OptionsRenderer.java:193)
at org.apache.tiles.extras.renderer.OptionsRenderer.renderAttempt(OptionsRenderer.java:136)
at org.apache.tiles.extras.renderer.OptionsRenderer.render(OptionsRenderer.java:123)
at org.apache.tiles.request.render.ChainedDelegateRenderer.render(ChainedDelegateRenderer.java:68)
at org.apache.tiles.impl.BasicTilesContainer.render(BasicTilesContainer.java:259)
at org.apache.tiles.template.InsertAttributeModel.renderAttribute(InsertAttributeModel.java:188)
at org.apache.tiles.template.InsertAttributeModel.execute(InsertAttributeModel.java:132)
at org.apache.tiles.jsp.taglib.InsertAttributeTag.doTag(InsertAttributeTag.java:299)
at org.apache.jsp.WEB_002dINF.conf.tiles3.page.page_jsp._jspx_meth_tiles_005finsertAttribute_005f0(page_jsp.java:539)
at org.apache.jsp.WEB_002dINF.conf.tiles3.page.page_jsp._jspService(page_jsp.java:246)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443)
at org.apache.jasper.servlet.JspServlet._serviceJspFile(JspServlet.java:386)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:40001)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

Issue Links

• links to: GitHub Pull Request #14