This may be a strange question, but do 'try-catch' blocks add any more to memory in a server environment than just running a particular block of code. For example, if I do a print stack trace, does the JVM hold on to more information. Or is more information retained on the heap?
try {
... do something()
} catch(Exception e) {
e.printStackTrace();
}
... do something()
The exception will hae a reference to the stack trace. printStackTrace will allocate more memory as it formats that stack trace into something pretty.
The try catch block will likely result in a largely static code/data segment but not in run time memory allocations
The important here is as soon the exception variable 'e' is no longer reachable (ie, out of scope) it becomes eligible for memory collection.
Technically the answer to your question is probably no. There are lots of reasons to avoid throwing Exceptions whenever possible, but memory isn't really a concern.
The real reason to only throw Exceptions for truly exceptional conditions is that it's SLOW. Generating an exception involves carefully examining the stack. It's not a fast operation at all. If you're doing it as part of your regularly flow of execution, it will noticeably affect your speed. I once wrote a logging system that I thought was extremely clever because it automatically figured out which class had invoked it by generating an Exception and examining the stack in that manner. Eventually I had to go back and take that part out because it was noticeably slowing everything else down.
The stack trace is built when the exception is created. Printing the stack trace doesn't do anything more memory intensive than printing anything else.
The try/catch block might have some performance overhead, but not in the form of increased memory requirements.
For the most part, don't worry about memory/performance when exceptions happen. If you have an exception that is a common code path then that suggest you are misusing exceptions.
If your question is more for academic purposes, then I don't know the full extent of what is going on there in terms of heap/memory space. However, Joshua Bloch in "Effective Java" mentions that the catch block of the try catch block is often relatively unoptimized by most JVM implementations.
While not directly related to memory consumption, there was a thread here a while back discussing How slow are the Java exceptions? It is worth a look, in my opinion.
I also had this link in my bookmarks. As far as I can recall, it gave an example of speed up possible when stack trace generation is skipped on exception throw, but the site seems down now.
