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copied!<p>The general rule of thumb for exception is, if you can do something about it, catch it and handle it, if you can't, re-throw it to the next method. To get into some of your specifics:</p> <ol> <li>No, using excessive try/catch will not have a performance impact</li> <li>Using the most specific type of exception you can. For example, you shouldn't generally throw Exception if you can avoid it. By throwing a specific type, you are letting the user know what can go wrong. However, you can rethrow it as something more generic so callers that are not concerned with the specific exception don't need to know about it (for example, a GUI won't care if it's an IOException vs an ArrayIndexOutOFBoundsException).</li> <li>You will find people that like checked exceptions more and you will find people that like unchecked more. In general, I try to use unchecked exceptions because there is generally not a lot you can do about most checked exceptions, and you can still handle unchecked exceptions, you just don't have to. I frequently find myself rethrowing checked exceptions since I can't do much about them (another strategy is to catch a checked exception and rethrow it as an unchecked so classes higher in the chain don't need to catch it if they don't want).</li> </ol> <p>I generally like to log exceptions at the point of where they are caught - even if I can't do anything about it, it helps to diagnose the problem. If you are not familiar with it, also look into the method Thread.setDefaultUncaughtExceptionHandler. This allows you to handle exceptions that are not caught by anyone and do something with it. This is particularly useful with a GUI app since the exception might otherwise not be seen.</p> <p>To get into some examples:</p> <pre><code>try { // some database operation } catch (IOException ex) { // retry the database operation. then if an IO exception occurs rethrow it. this shows an example doing something other than just catch, logging and/or rethrowing. } </code></pre> <p>I'll be happy to expand on any parts of this if you'd like.</p>

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