Siva,
The first thing I would check are the columns being displayed. If you are displaying a column that is an external attribute, Spectrum would have to run a snmpget for the info. If the device is not responding to snmp then it would cause the issue.
You say you have 16GB of free memory. How much memory is configured for tomcat?
If this is the OneClick console, how much memory is configured for the JRE client?
If this is WebApp, how much memory is configured for WebTomcat?
Joe