Hi, >There *is* such things as immutable collections.
Actually, there are two kinds of immutable collections: (a) read-only (b) copy-on-write For (a) Java has built-in support, while for (b) there is only java.util.concurrent.CopyOnWrite*. For copy-on-write collections, usually add and remove methods return a new collection. If we need more (b), such as maps, we might want to add an external library or write our own (where performance and memory usage is critical). But even then, we don't really need a new programming language. Actually, there is a bit of (b) in the Jackrabbit 3 sandbox already (org.apache.jackrabbit.mk.mem.NodeImpl, methods createClone and cloneAnd*). Regards, Thomas
