DHT22 sensor bought from Amazon and Raspberry PI 2(Model B).
1) Wire Pin 1(VDD) of DHT22 to Pin 1(+3.3v) of PI
2) Wire Pin 2(DATA) of DHT22 to Pin 7(GPIO4) of PI
3) Wire Pin 3(GND) of DHT22 to Pin 9(GND) of PI
Some tutorials require 10K resistor between wires of PIN1 and PIN2 of DHT22 sensor. I haven't used the resistor.
I tried with pi4j for java and it didn't work. I then tried in C using wiringpi. It worked with no issues. Went ahead with C and JNI. JNI to interface C and Java. I wanted Java to read and post measurements to Elasticsearch for graph.
Install wiringpi library as in the documentation.