Field displayer raise NullPointerException when object field has never been set

XWikiDocument:display:1305 - Exception showing field blogfeed
java.lang.NullPointerException
	at com.xpn.xwiki.objects.classes.PropertyClass.displayView(PropertyClass.java:150)
	at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:1280)
	at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:1260)
	at com.xpn.xwiki.api.Document.display(Document.java:855)
	at sun.reflect.GeneratedMethodAccessor74.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:248)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203)
	at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:419)
	at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:73)
	at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:125)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.render(XWikiVelocityRenderer.java:91)
	at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:229)
	at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:161)
	at com.xpn.xwiki.XWiki.include(XWiki.java:2996)
	at com.xpn.xwiki.api.XWiki.includeForm(XWiki.java:1299)
	at com.xpn.xwiki.api.XWiki.includeForm(XWiki.java:1265)
	at sun.reflect.GeneratedMethodAccessor175.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:248)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:294)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:194)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:170)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.render(XWikiVelocityRenderer.java:91)
	at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:229)
	at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:161)
	at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderText(DefaultXWikiRenderingEngine.java:132)
	at com.xpn.xwiki.render.DefaultXWikiRenderingEngine.renderDocument(DefaultXWikiRenderingEngine.java:124)
	at com.xpn.xwiki.doc.XWikiDocument.getRenderedContent(XWikiDocument.java:351)
	at com.xpn.xwiki.api.Document.getRenderedContent(Document.java:336)
	at sun.reflect.GeneratedMethodAccessor160.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:248)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:294)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1223)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1202)
	at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:489)
	at sun.reflect.GeneratedMethodAccessor49.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:295)
	at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:248)
	at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:203)
	at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:294)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:194)
	at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:170)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:74)
	at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:88)
	at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:74)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:107)
	at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:240)
	at com.xpn.xwiki.render.XWikiVelocityRenderer.evaluate(XWikiVelocityRenderer.java:143)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1223)
	at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:1202)
	at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:98)
	at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:159)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
	at com.xpn.xwiki.web.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:121)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
	at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
	at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
	at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
	at java.lang.Thread.run(Thread.java:595)