FreeMarker template error!


get(contentView) failed on instance of org.noe.pigai.forum.model.PgForumPost
The problematic instruction:
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==> ${bean.contentView!} [on line 67, column 88 in front/forum/thread_single_index.ftl]
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Java backtrace for programmers:
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freemarker.template.TemplateModelException: get(contentView) failed on instance of org.noe.pigai.forum.model.PgForumPost
	at freemarker.ext.beans.BeanModel.get(BeanModel.java:224)
	at freemarker.core.Dot._getAsTemplateModel(Dot.java:76)
	at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)
	at freemarker.core.DefaultToExpression._getAsTemplateModel(DefaultToExpression.java:100)
	at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)
	at freemarker.core.Expression.getStringValue(Expression.java:93)
	at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:167)
	at freemarker.core.Environment.visit(Environment.java:428)
	at freemarker.core.IteratorBlock.accept(IteratorBlock.java:102)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.process(Environment.java:199)
	at freemarker.template.Template.process(Template.java:259)
	at org.noe.yfw.web.RequestContext.outFtl(RequestContext.java:950)
	at org.noe.yfw.web.RequestContext.outFtl(RequestContext.java:919)
	at org.noe.pigai.web.bbs.IndexAction.hander2(IndexAction.java:246)
	at org.noe.pigai.web.bbs.IndexAction.process(IndexAction.java:139)
	at sun.reflect.GeneratedMethodAccessor274.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.noe.yfw.web.filter.GlobalFilter.doFilter(GlobalFilter.java:129)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
	at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:683)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.GeneratedMethodAccessor204.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at freemarker.ext.beans.BeansWrapper.invokeMethod(BeansWrapper.java:866)
	at freemarker.ext.beans.BeanModel.invokeThroughDescriptor(BeanModel.java:277)
	at freemarker.ext.beans.BeanModel.get(BeanModel.java:184)
	... 43 more
Caused by: java.lang.NullPointerException
	at org.noe.pigai.util.AttachTagFilter.filter(AttachTagFilter.java:25)
	at org.noe.pigai.util.TagFilterUtil.handlerFilter(TagFilterUtil.java:38)
	at org.noe.pigai.forum.model.PgForumPost.getContentView(PgForumPost.java:229)
	... 49 more