Android 4.4 can use printer over Wi-Fi? I searched on printing using wifi printer and I came to know that Android 4.4 can do this (Android apps can now print any type of content over Wi-Fi) but I did not found any idea how to connect to wifi printer and give it command to print. Only I found that I can do this using Google cloud print (what if I want to use only wifi not the concept of Google cloud print). And provide me suggestion if it is possible (1. detect available wifi printer 2. connect to one 3.give command to print)

I found similar app PrintBot, PrinterShare , iCanPrint, but unable to guess "How they accomplish this?" I found some are using Google Cloud Print! 

Something similar to Apple AirPrint
As the link you provided mentions, "Printer manufacturers can use new APIs to develop their own print services — pluggable components that add vendor-specific logic and services for communicating with specific types of printers."

This means that the printer manufacturer has to supply an app to enable direct printing over WiFi. Without this, cloud-based services like Google Cloud Print are you only options.