I don't fully understand the String.intern() method. I understand the
purpose, but to be able to call String.intern(), don't you need to
create a new instance of a String to then check if it has already been
created? (The same thought that Rich D had about his Interner class). I thought that the functionality of String.intern() is something that
the JRE performs by default, as opposed to having to be called manually.
I think the point is to (a) reduce memory usage and (b) increase the efficiency of comparisons. Once example of intern() in action is in Jython.
Jython interns all identifiers when it parses them. This means it can perform comparisons and lookups very efficiently. Also, size of the program is reduced since identifiers are only stored in memory once.
Each identifier is created as a separate object when it is parsed. After the identifier has been interned, the original object would be garbage collected. So, using intern() doesn't reduce the amount of object creation. But, for Jython, the performance and memory benefits made intern() worthwhile.
This thread started as an idea for an object that combined a factory with a pool to (a) reduce memory usage, (b) increase the efficiency of comparisons and (c) reduce the amount of object creation/garbage collection. String.intern() and the Interner class I posted can provide (a) and (b), but don't address (c).
Rich
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