Why node js is called single threaded?
Does all code runs in a single thread?
How is perform asynchronous task even after being single threaded?
Each task waits for any previous task to be completed and is executed only then. In asynchronous programming, when one task is executed, you can switch to a different task without waiting for the previous one to be completed.
Is Python a single threaded language?
The short answer is yes, they are single threaded. The long answer is it depends. JRuby is multithreaded and can be run in tomcat like other java code. MRI (default ruby) and Python both have a GIL (Global Interpreter Lock) and are thus single threaded.