Step 1: Download JDK
Here is the link to download the JDK DOWNLOAD. Note: download the JDK that matches with your operating system i.e. download x64 version of JDK if you have x64 bit operating system for better performance.
Step 2: Download Eclipse
Download and install Eclipse from its official site. You can download any flavor of Eclipse i.e. Helios, Indigo, Galileo, Juno etc. But I prefer Eclipse Indigo. Note: download the Eclipse that matches with your operating system version.
Step 3: Download and Install ADT Plugin
