How to run java

How do I set or change the PATH system variable?

This article applies to:

Platform(s): Macintosh OS X, Oracle Linux, Red Hat Linux, SUSE Linux, Solaris SPARC, Windows 7, Windows 8, Windows Vista, Windows XP

The instructions on this page are intended for advanced users or system administrators.

General Information

The PATH is the system variable that your operating system uses to locate needed executables from the command line or Terminal window.

The PATH system variable can be set using System Utility in control panel on Windows, or in your shell's startup file on Linux and Solaris.

Making changes to the system PATH variable is typically not necessary for computers running Windows or Mac OS X.

How to SET PATH JAVA in Windows

How to SET PATH JAVA in Windows 10 and Windows 8

In Search, search for and then select: System (Control Panel)
Click the Advanced system settings link.
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.
Reopen Command prompt window, and run your java code.

How to SET PATH JAVA in Windows 7

From the desktop, right click the Computer icon.
Choose Properties from the context menu.
Click the Advanced system settings link.
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.
Reopen Command prompt window, and run your java code.

How to SET PATH JAVA in Windows Vista

From the desktop, right click the My Computer icon.
Choose Properties from the context menu.
Click the Advanced tab (Advanced system settings link in Vista).
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.
Reopen Command prompt window, and run your java code.

How to SET PATH JAVA in Windows XP

Select Start, select Control Panel. double click System, and select the Advanced tab.
Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.
Reopen Command prompt window, and run your java code.

How to set path java in Mac OS X

To run a different version of Java, either specify the full path, or use the java_home tool:

% /usr/libexec/java_home -v 1.8.0_73 --exec javac -version

How to do JAVA SET PATH for Solaris and Linux

To find out if the path is properly set:
In a terminal windows, enter:
% java -version
This will print the version of the java tool, if it can find it. If the version is old or you get the error java: Command not found, then the path is not properly set.

Determine which java executable is the first one found in your PATH
In a terminal window, enter:
% which java

How to do JAVA SET PATH permanently

To set the path permanently, set the path in your startup file.
Note: Instructions for two most popular Shells on Linux and Solaris are listed. If you are using other shells, see the Path Setting Tutorial.

Bash Shell

Edit the startup file (~/.bashrc)

Modify PATH variable
PATH=/usr/local/jdk1.8.0/bin:$PATH
export PATH
Save and close the file
Load the startup file
% . /.profile
Verify that the path is set by repeating the java command
% java -version

C Shell (csh)

Edit the startup file (~/.cshrc)

Set Path
set path=(/usr/local/jdk1.8.0/bin $path)
Save and close the file
Load the startup file
% source ~/.cshrc
Verify that the path is set by repeating the java command
% java -version

HOW TO SET PATH and CLASSPATH TO KNOW HOW TO RUN JAVA


1) This section explains how to use the PATH and CLASSPATH environment variables on Microsoft Windows, Solaris, and Linux. Consult the installation instructions included with your installation of the Java Development Kit (JDK) software bundle for current information.

After installing the software, the JDK directory will have the structure shown below.
JDK directory structure

The bin directory contains both the compiler and the launcher.
Update the PATH Environment Variable (Microsoft Windows)

You can run Java applications just fine without setting the PATH environment variable. Or, you can optionally set it as a convenience.

Set the PATH environment variable if you want to be able to conveniently run the executables (javac.exe, java.exe, javadoc.exe, and so on) from any directory without having to type the full path of the command. If you do not set the PATH variable, you need to specify the full path to the executable every time you run it, such as:

C:\Java\jdk1.7.0\bin\javac MyClass.java

The PATH environment variable is a series of directories separated by semicolons (;). Microsoft Windows looks for programs in the PATH directories in order, from left to right. You should have only one bin directory for the JDK in the path at a time (those following the first are ignored), so if one is already present, you can update that particular entry.

The following is an example of a PATH environment variable:

C:\Java\jdk1.7.0\bin;C:\Windows\System32\;C:\Windows\;C:\Windows\System32\Wbem

It is useful to set the PATH environment variable permanently so it will persist after rebooting. To make a permanent change to the PATH variable, use the System icon in the Control Panel. The precise procedure varies depending on the version of Windows:
Windows XP

    Select Start, select Control Panel. double click System, and select the Advanced tab.
    Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
    In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.

Windows Vista:

    From the desktop, right click the My Computer icon.
    Choose Properties from the context menu.
    Click the Advanced tab (Advanced system settings link in Vista).
    Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
    In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.

Windows 7:

    From the desktop, right click the Computer icon.
    Choose Properties from the context menu.
    Click the Advanced system settings link.
    Click Environment Variables. In the section System Variables, find the PATH environment variable and select it. Click Edit. If the PATH environment variable does not exist, click New.
    In the Edit System Variable (or New System Variable) window, specify the value of the PATH environment variable. Click OK. Close all remaining windows by clicking OK.

Note: You may see a PATH environment variable similar to the following when editing it from the Control Panel:

%JAVA_HOME%\bin;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem

Variables enclosed in percentage signs (%) are existing environment variables. If one of these variables is listed in the Environment Variables window from the Control Panel (such as JAVA_HOME), then you can edit its value. If it does not appear, then it is a special environment variable that the operating system has defined. For example, SystemRoot is the location of the Microsoft Windows system folder. To obtain the value of a environment variable, enter the following at a command prompt. (This example obtains the value of the SystemRoot environment variable):

echo %SystemRoot%

Update the PATH Variable (Solaris and Linux)

You can run the JDK just fine without setting the PATH variable, or you can optionally set it as a convenience. However, you should set the path variable if you want to be able to run the executables (javac, java, javadoc, and so on) from any directory without having to type the full path of the command. If you do not set the PATH variable, you need to specify the full path to the executable every time you run it, such as:

% /usr/local/jdk1.7.0/bin/javac MyClass.java

To find out if the path is properly set, execute:

% java -version

This will print the version of the java tool, if it can find it. If the version is old or you get the error java: Command not found, then the path is not properly set.

To set the path permanently, set the path in your startup file.

For C shell (csh), edit the startup file (~/.cshrc):

set path=(/usr/local/jdk1.7.0/bin $path)

For bash, edit the startup file (~/.bashrc):

PATH=/usr/local/jdk1.7.0/bin:$PATH
export PATH

For ksh, the startup file is named by the environment variable, ENV. To set the path:

PATH=/usr/local/jdk1.7.0/bin:$PATH
export PATH

For sh, edit the profile file (~/.profile):

PATH=/usr/local/jdk1.7.0/bin:$PATH
export PATH

Then load the startup file and verify that the path is set by repeating the java command:

For C shell (csh):

% source ~/.cshrc
% java -version

For ksh, bash, or sh:

% . /.profile
% java -version

Checking the CLASSPATH variable (All platforms)

The CLASSPATH variable is one way to tell applications, including the JDK tools, where to look for user classes. (Classes that are part of the JRE, JDK platform, and extensions should be defined through other means, such as the bootstrap class path or the extensions directory.)

The preferred way to specify the class path is by using the -cp command line switch. This allows the CLASSPATH to be set individually for each application without affecting other applications. Setting the CLASSPATH can be tricky and should be performed with care.

The default value of the class path is ".", meaning that only the current directory is searched. Specifying either the CLASSPATH variable or the -cp command line switch overrides this value.

To check whether CLASSPATH is set on Microsoft Windows NT/2000/XP, execute the following:

C:> echo %CLASSPATH%

On Solaris or Linux, execute the following:

% echo $CLASSPATH

If CLASSPATH is not set you will get a CLASSPATH: Undefined variable error (Solaris or Linux) or simply %CLASSPATH% (Microsoft Windows NT/2000/XP).

To modify the CLASSPATH, use the same procedure you used for the PATH variable.

Class path wildcards allow you to include an entire directory of .jar files in the class path without explicitly naming them individually. For more information, including an explanation of class path wildcards, and a detailed description on how to clean up the CLASSPATH environment variable, see the Setting the Class Path technical note.