FxGen

Very good explanation, why one should be careful to not duplicate Strings!
@Bristol, Typically the extra costs of String.intern are minimal compared to the increase in memory usage.
Often you would hold a copy of a certain String for each user, which means for n users you will need n times more memory for this String. The problem with intern as mentioned before is that it eats up your PermGen slowly and surely cissp certification.
If the String you create is a result of user input, you will have your PermGen constantly increasing up until the inevitable OutOfMemoryError is thrown!
Also, for something that was said earlier, you really do keep only the subset of chars; see String’s implementation for reference.
This advice can have bad side-effects. A string object is actually just a view on an underlying char[]. If the char[ cissp exam] is very large, and the view very small (as can often happen with using substring on a large string such as xml) then your advice would end up caching the whole large char[] even though you are only using a small fraction of it. And this is a cache that can never be freed.
In general, String.intern() is a pretty low-level method (originally designed for JVM/compiler caching) and great care should be taken when using it in your own code ccna exam questions.