Is netbackup " java" console affect the server performance?

Where are you running the Java Console? On the NBU server or from your Windows desktop?
I have not experienced Master server performance issues when Java Console is run on Windows desktop.

Is netbackup " java" console affect network bandwith? 

It all depends on where you running the Java Console:
On the master server: Yes
On your Windows desktop: No
 

how can I determine the Java console session number?

No sure what you mean with this question. Please explain?

how can I determine the java console users? 

Currently logged in or just a list of authorised users?
Start with auth.conf file in /usr/openv/java.
Enable logging for Java users:  /usr/openv/netbackup/logs/bpjava-susvc 
Other logs that may be useful:
bpjava-msvc
bpjava-usvc

Thank You marianne.

--how can I determine the Java console session number?
I mean , how can I have a control for misusing "Java console"?
(( I want to prevent some users and allow others))

-- I want to prevent all user from opening a direct "Java console" on Master Backup.

look at /usr/openv/java/auth.conf for controlling what can be done by a user.
use bpps and kill for users that login directly to master.

NBAC also should be helpful enough with Java console login more over  You can explicitely set permissions on wht multiple backup admins can do with NBU

Give a try 

Dear Stumpr,

How can I use bpps and kill for users that login directly to master?

Thanks