Today morning my application (connected to oracle thru Jrun) stopped responding and I diagnosed the problem is with Oracle. I went into the SQL prompt and tried to stop the database, when I found the mesage :
ORA-00020: maximum number of processes (150) exceeded
Tried to stop oracle for so long and I failed. Since the situation went critical, I was forced to restart the whole system. I got an idea of the problem as the number of connections has exceeded the specified limit.

Oracle was not responding to my "shutdown" command too. I don't know what to be done on such a situation and hence I restarted the whole system, even though I knew that it shouldn't be done. Is there any other way to force shutdown oracle in such a situation ?

I googled and found some solutions to rectify this limitation - to increase the max. number of connections. I found a SQL statement that will increase the number of connections.
SQL> alter system set processes=200 scope=spfile;
In fact, I dont know the consequences of this command. Also I dont know the consequences of increasing the number of connections. Can someone help me on this ?