first commit !

Change-Id: If3acc1e3cb8c0d89f5e47f9f971b1c3a33d23d5d
Signed-off-by: Guopei Gong <gongguopei87@gmail.com>
add Hello.java
alter GitMain.java

Signed-off-by: Guopei Gong <gongguopei87@gmail.com>