Q: Creating Jenkins slave throws error I am getting below error while creating new node on Jenkins(2.84) running on Windows 2012 server. 
org.apache.commons.jelly.JellyTagException: jar:file:/D:/Softwares/buildTools/Jenkins/war/WEB-INF/lib/jenkins-core-2.84.jar!/lib/form/descriptorList.jelly:84:76: <st:include> org.apache.commons.jelly.JellyTagException: jar:file:/D:/Softwares/buildTools/Jenkins/war/WEB-INF/lib/jenkins-core-2.84.jar!/lib/form/nested.jelly:33:22: <d:invokeBody> Cannot get property 'class' on null object
    at org.apache.commons.jelly.impl.TagScript.handleException(TagScript.java:726)
    at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:281)
    at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
    at org.kohsuke.stapler.jelly.CallTagLibScript$1.run(CallTagLibScript.java:99)
    at org.apache.commons.jelly.tags.define.InvokeBodyTag.doTag(InvokeBodyTag.java:91)
    at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:269)
    at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
    at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:161)
    at org.apache.commons.jelly.tags.core.WhenTag.doTag(WhenTag.java:46)
    at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:269)
    at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
    at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:161)
    at org.apache.commons.jelly.tags.core.ChooseTag.doTag(ChooseTag.java:38)
    at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:269)
    at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
    at org.apache.commons.jelly.tags.core.CoreTagLibrary$2.run(CoreTagLibrary.java:105)
    at org.kohsuke.stapler.jelly.CallTagLibScript.run(CallTagLibScript.java:120)
    at org.apache.commons.jelly.TagSupport.invokeBody(TagSupport.java:161)
    at org.apache.commons.jelly.tags.core.ForEachTag.doTag(ForEachTag.java:150)
    at org.apache.commons.jelly.impl.TagScript.run(TagScript.java:269)
    at org.apache.commons.jelly.impl.ScriptBlock.run(ScriptBlock.java:95)
    at org.kohsuke.stapler.jelly.CallTagLibScript$1.run(CallTagLibScript.java:99)
    at org.apache.commons.jelly.tags.define.InvokeBodyTag.doTag(InvokeBodyTag.java:91)

Can some one help me fix this issue.
