trying to install CQ public instance ?

Hi Brijesh Yadav,

java -jar cq-author-p4502.jar
Loading quickstart properties: default
Loading quickstart properties: instance
Low-memory action set to fork
Using 32bit VM settings, min.heap=768MB, min permgen=192MB, default fork arguments=[-Xmx768m, -XX:MaxPermSize=192m]
**** WARNING: insufficent heap memory ******************************************
The JVM reports 247 MB but we recommend at least 768 MB +/- 20
Use your JVM's heap size option (like -Xmx768M) to set that size.
Will fork a JVM to get enough memory.
********************************************************************************
**** WARNING: insufficent PermGen memory ***************************************
The JVM MBean:Perm Gen reports 64 MB but we recommend at least 192 MB +/- 20
Use your JVM's PermGen size option (like -XX:MaxPermSize=192M) to set that size.
Will fork a JVM to get enough memory.
********************************************************************************
Available memory below specified limits and low-memory action set to fork, will fork to get enough memory
Preparing to fork JVM, OS name=Linux, isWindows=false
Forking JVM: [/usr/java/jdk1.7.0_09/jre/bin/java, -Xmx768m, -XX:MaxPermSize=192m, -jar, /home/author/cq-author-p4502.jar, -nofork, -pt, CHILD]
Loading quickstart properties: default
Loading quickstart properties: instance
Low-memory action set to fork
Using 32bit VM settings, min.heap=768MB, min permgen=192MB, default fork arguments=[-Xmx768m, -XX:MaxPermSize=192m]
**** WARNING: insufficent heap memory ******************************************
The JVM reports 742 MB but we recommend at least 768 MB +/- 20
Use your JVM's heap size option (like -Xmx768M) to set that size.
Will fork a JVM to get enough memory.
********************************************************************************
The JVM MBean:Perm Gen reports a maximum size of 192 MB, meets our expectation of 192 MB +/- 20
Available memory below specified limits and low-memory action set to fork, will fork to get enough memory
Not forking JVM as -nofork option is set
Setting properties from filename '/home/author/cq-author-p4502.jar'
Option '-quickstart.server.port' set to '4502' from filename cq-author-p4502.jar
Verbose option not active, closing stdin and redirecting stdout and stderr
Redirecting stdout to /home/author/crx-quickstart/logs/stdout.log
Redirecting stderr to /home/author/crx-quickstart/logs/stderr.log

There are a few reasons why this may happen. If, for example, Java is not set-up properly. I recommend that you consult this AEM troubleshooting information: http://dev.day.com/docs/en/cq/5-5/deploying/installing_cq.html#Troubleshooting. 

i went through that link.. it was not helpful.

Thanks

Mahesh

A few questions:
1) Are you running it from the correct directory ?
2) Are all the right permissions set for the jar and the folder in which you have it ? 
3) Are you running the publish instance as a user that have the permission to do so ?

It would be good to get some more information of how you have it setup and how you try to start it
Regards
/Johan

ALong with Johan recommendation Make sure
    *    The jar file name in command matches with the file system
    *     You are executing the command from directory jar exists.

Hi Johan, Sham,

Have proper permissions.

ya i am executing the command from the directory jar exists.

jar name and jar file name in the command are same.

Then it is permission issue or jar file not downloaded completely. Could you place download the fresh jar in the another directory where you have full access & try it out again