# 3) Java setup

**Java Set Up**

For Executing Java program, you need to 

* Download  and Install JDK (from [www.oracle.com](http://www.oracle.com))
* Set path of the Jdk/bin Directory
* Create the java program
* Compile and run the Java program

**Path Variable**

Path variable is set for providing path for all java tools like java, javac, javap, javah, jar, applet viewer which are used in java programming. These all tools are available in **bin** folders so we set path up to bin folders.

**Classpath Variable**

**Classpath** variable is set for providing path for predefined java classes which is used in our application. All classes are available in **lib/rt.jar** so we set classpath upto lib folder.

**JDK Folder Hierarchy**

**C:\Program Files\Java\jdk1.8.0\_102\bin**

This folder contains tools like java, javac, javap, javah, jar, appletviewer etc.

**C:\Program Files\Java\jre1.8.0\_102\lib**

This folder contains **rt.jar** which contains all the predefined Java classes

**Why set path?**

To execute java console based programs in windows environment we have to use **java** and **javac** commands. Since, **java** and **javac** commands are unknown for windows till we do not specify explicitly where those executable resides.

The following programming error is general for all java programmers when they compile any java program without set up the path.

**'javac'** **is not recognized as an internal or external command, operable program or batch file.**

When you get this type of error, then your operating system cannot find the java compiler **(javac)**. To solve this error, you need to set the PATH variable.

**Javac** is a tool which is available in bin folder so you must set the PATH upto bin folder. In a **bin** folder all tools are available like **javap, javah, jar, javac, java, appletviewer** etc. These all tools are used for different-different purpose.

**How to set the path and classpath**

Go to My Computer icon and right click ->click on properties option-> click on advance System setting -> Click on Environment Variables -> Select on **path** which is under second box (System variable Section). -> Click on edit -> Do not delete anything on variable value, just put a semicolon at the end and paste the bin path (**C:\Program Files\Java\jdk1.8.0\_102\bin)**

Again put one more semicolon at the end and paste the lib path.

(**C:\ProgramFiles\Java\jre1.8.0\_102\lib)**

You are done with path setting.

Restart your system

**How to check whether java is installed on your computer?**

Ans-Open command prompt->type ->java –version press Enter

If java is correctly installed then you will get something like this

java version "1.8.0\_144"

Java(TM) SE Runtime Environment (build 1.8.0\_144-b01)

Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

Everything is done. It’s time to write program.