If you get the message "The service URL is invalid" while accessing deployed business components with multiple concurrent users, your large pool size and shared pool size may be too small.
Business Components for Java deployed as EJBs work best with a large pool size and shared pool size of at least 50MB per concurrent user. Edit your init.ora file and check the large_pool_size and shared_pool_size parameters. If they are less than 50MB times the estimated maximum number of concurrent users, change them, restart your database, and try your connection again.