Start ADT Android  SDK with Ubuntu

Today, I try to develop my apps with ADT on Ubuntu 14.04
The problem is jdk is not installed, and the second I can not read file by extension RAR.

The solution is
1. Open terminal, unsure that connect internet and type some command below.

sudo apt-get install openjdk-7-jre

We need to install either the openjdk-7-jre or oracle-java7-jre package.

2. About RAR problem I get solution , we open the terminal, and type this command

apt-get install unrar

To extract the file RAR we just type

unrar x myrararchive.rar