Just in case you install Android Studio and its SDK Tools separately, you need to setup JDK as shown below:

Installation and Configuration of JAVA Development Kit (JDK)

Download java on the following link:

http://www.oracle.com/technetwork/java/javase/downloads/index.html

The above link will download all your necessary JAVA files. It will show all the ways to download and configure the JAVA setup. Make a directory by the name of ‘JAVA_HOME’ to store files and variable to refer the directory that consist of java and javac. And will save java_install_dir/bin and java_install_dir both.

For windows: after installing the JDK file in C:\jdk1.8.0_102, you will have to write the following line in the C:\autoexec.bat.file:
set PATH=C:\jdk1.8.0_102\bin;%PATH%
set JAVA_HOME=C:\jdk1.8.0_102

Another way to do it is that you can click on ‘My Computer’ select ‘Properties’ then click on ‘Advanced’ then click on ‘Environment Variables’ then update the PATH value and press OK.

For LINUX: after the SDK is installed in /usr/local/jdk1.8.0_102 and use the C shell. Write the following code in .cshrc file
setenv PATH /usr/local/jdk1.8.0_102/bin:$PATH
setenv JAVA_HOME /usr/local/jdk1.8.0_102/

Note that: You will be able to start your Android app on:

• Windows XP or any version available after XP
  
• MAC OS X 10.5.8 or any version available after it
  
• LINUX 2.7 or any version available after it
  

You can work with:

• JAVA JDK5 or any version available after it
  
• Android Studio
  

Book traversal links for Installation and Configuration of JAVA Development Kit (JDK)

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