Null pointer anomaly in Ararylist

Question

First, i initialized my ArrayList to null, then I tried to initialize it with a String, but it doesn't overwrite the String. Now I initialize my ArrayList with another ArrayList containing a String and it works, can someone explain it? (implementation is done in java)

Can you show the problematic and successful code? – The Head Rush Mar 17 '17 at 20:05 — The Head Rush, Mar 17 '17 at 20:05
Please add the source code, so we can help you. – reos Mar 17 '17 at 20:34 — reos, Mar 17 '17 at 20:34
Can't imagine what you are saying. Please post a snippet. – robot_alien Mar 17 '17 at 20:34 — robot_alien, Mar 17 '17 at 20:34

score -1 · Answer 1 · answered Mar 17 '17 at 20:40

// This creates a new ArrayList paramaterized to store Strings
ArrayList<String> list = new ArrayList<String>();

You can call various methods on list, now, such as add or remove, and you get do this at a specific index, just like you would with an array. The difference is the ArrayList can grow or shrink in size.

For some examples:

https://www.tutorialspoint.com/java/java_arraylist_class.htm

Null pointer anomaly in Ararylist

1 Answers1