Why arraylist is not synchronized

This is the reason, SqlDataReader is faster than Dataset. ConcurrentHashMap is, indeed, threadsafe. A good practice will be to use one of the atomic methods implemented by ConcurrentHashMap , i. Create a bunch of keys that all have the same hashcode say 30 or 40 Add values to the map for each key. Spawn a separate thread for the key, which has an infinite loop that 1 asserts that the key is present int the map, 2 removes the mapping for that key, and 3 adds the mapping back.

Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Skip to content Why ArrayList is non synchronized? Which is better ArrayList or vector? Is HashMap thread-safe? Is a vector thread-safe?

Is HashMap synchronized? Is linked list is synchronized? LinkedList Features LinkedList maintains the insertion order of the elements. Is the LinkedList synchronized? Is TreeSet synchronized? Is StringBuffer thread-safe? StringBuffer is synchronized and therefore thread-safe. Second , there is instance synchronization. Here we not only prevent concurrent method calls, but we make sure that only one thread has access to the list object for a time.

This is important if you have pieces of logic that require that the list remains in an unchanged state until the logic is done. For example iterating over lists. You don't want other threads to add elements while you iterate over a list. Python Javascript Linux Cheat sheet Contact. Save Article. Improve Article. Like Article. Recommended Articles.

Limitations of synchronization and the uses of static synchronization in multithreading. Article Contributed By :. Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. What's New. The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa. The returned list supports all of the optional list operations supported by this list.

Here's an example of putting a few of these things together:. HTTP -- that is the actual transport protocol between the server and the client -- is "stateless" because it remembers nothing between invocations.

There is simply no state kept at the server at the protocol level that will have the server know anything about you as you come in. Well, that's true for HTTP up to 1. HTTP 1. We'll overlook this for the moment because they don't really make HTTP stateful, they just make it dirty-stateless instead of pure-stateless.

To help you understand the difference, imagine that a protocol like Telnet or SSH were stateless. If you wanted to get a directory listing of a remote file, you would have to, as one atomic operation, connect, sign in, change to the directory and issue the ls command. When the ls command finished displaying the directory contents, the connection would close.

If you then wanted to display the contents of a specific file you would have to again connect, sign in, change to the directory and now issue the cat command. When the command displaying the file finished, the connection would again close.