That is a good question. When you want to modify a component - the typical way is to use Overlay - as described here: Overlays Also a very good answer here too: cq5 - overlay/overriding v/s extending of components in AEM - Stack Overflow

Please provide more information - did this start of all a sudden and used to work. Has anyone put on custom code into the server that may have somehow produced this condition. If you test on a fresh AEM instance - you will notice that works fine.

Another test to try is see if you can hit a custom submit action on pub - this will tell us if there is a serious issue with the Pub instance. See Adobe Experience Manager Help | Submitting Adaptive Form Data to MySQL using a DataSourcePool . This should work on Pub - if Pub is functioning normally

We just updated the article that talks about how to query JCR data. Its important to know how to do this.Adobe Experience Manager Help | Querying Adobe Experience Manager 6.4 JCR dataThis use case will build a HTL component that displays JCR data in a GRID - see this - it shows the HTL component wor...

This would be no different then standard overlay as discussed here -- Overlays

See if this community article helps you -- AEM Tips and Tricks: Customizing the default parsys text of AEM using Sightly code

When they overlayed this part of the AEM code base - what did they do? The error may be the result of the overlay changes.

" but i need to use jar file in my project"What are you trying to do? You asked for information on how to run AEM on an App Server. This assumes you have the AEM WAR file. If you have the Quick Start JAR - you start AEM by clicking on it. You do not need to run a standalone AEM Quick Start JAR on an...

Another team reply -- >>As a test, I tried to point Asset Reports>Files to /content/dam/collections For starters we send the query to look for dam:Asset type of nodes only [0], in its place we would need to send the following predicates to look up collections – group.0_property: sling:resourceTypeg...

You do not need to start AEM QUick Start JAR via an App server - simply double click on it.