java collections.
this page is just a big collection (hehe) of stuff i am learning about java.
** what is the collections framework?**
basically a java interface for using data structures like lists, sets, maps, and queues.
collection interface -> interfaces (lists, maps) -> classes (linked lists, hashmaps).
so arraylists comes from collections which is why it's so different from an array.
what is the list interface?
a list is dynamic, has index positioning, and allows duplicates. it is implemented by a bunch of different types of lists and is super fundamental.
arraylist is good at indexing and inserting at the start/end but slower for doing stuff in the middle bc stuff needs to shift around. not thread safe, will break and be unhappy.
linkedlists are faster than arraylist at start/end (3ms versus 300ms) but crazy slow at accessing data in the middle (5000ms versus 1ms). good for a queue.
vectors are thread safe, but not really used anymore bc there are better options like a synchronised arraylist.
stacks. love a good stack. also thread safe. dequeue might have better performance.
what's going on with sets?
they have all unique values (obvs) but we can either have them unordered (hashset), ordered by insertion (linkedhashset), or sorted (treeset). hashset is the main one.
exception handling