Java okhttp client trustall certificate (for test only).

Java REPL

In Java, static fields and static methods are common but how about static class? Here is an example.

A working example on how to config postfix with gmail smtp server to send email directly from linux command line and tested on vagrant vm with ubuntu precise 32.

Java multithreading programming demo.

A javascript calendar.

How to pretty print json usually for better visibility.

Common regular expression symbols, characters, and usage.

How to dynamically change html form action value based on user input.

Java parse common data files such as csv, json, yaml, xml, ini, properties and etc.