jakarta ee - Java EE programmers do not write to files

Question

Today one person told to me that "Java EE programmers do not write to files". Why can I not write to files from within a Java EE container (for example from JBoss)? What is wrong?

Answer 1

You should do everything within the Java EE container itself: you can have no certainty that you will have any consistent access to the filesystem. There are many reasons for this, the most obvious being that applications running within a container will have:

• no certainty that any subsequent invocation of an EJB would even be on the same physical server with access to the same files/filesystem (e.g. upon clustering)
• no possibility of interfering with each other (multiple applications attempting to write to the same file)
• no security issues (one app writing confidential data which another app could read)

You should also assume that you shouldn't:

• create your own threads (the container will manage this for you; if you create your own you may starve other applications in the container of CPU time)
• use socket-IO (also has security issues)