Java lazy initialization singleton instance pattern.

Java sort arrays in descending order.

Java bubble sort implementation.

Java binary search implementation.

Java 8 stream has a distinct() method which could be used to filter out a list of distinct objects, but the distinctness of that method is based on Object.equals(Object). What if you want to filter a list of objects based on any property (field) of the object? The StreamEx library comes as an elegant solution.

Python decorators are usually created with function, see another related post, but this post also shows an example on how to create decorators with class.

In Spring framework RestTemplate is very useful in terms of sending various http requests to RESTful resources and this post shows simple examples on how to set Content-Type, Accept headers, as well as the content encoding, which is especially important when requesting with non-ascii (e.g. CJK languages) data.

A quick guide on how to use celery to accomplish async task in application.

A simple web stack using flask, nginx, gunicorn and supervisor in python with minimum configuration. This is useful if you want to QUICKLY setup a simple but production ready web service.

A list of commands to do a quick migration for redis.