How do I check the CLASSPATH variable is set in my machine?

Checking CLASSPATH on Windows

To check CLASSPATH variable is set on Microsoft Windows, run following command on command prompt

C:> echo %CLASSPATH%

If CLASSPATH variable is not set you will see %CLASSPATH% on windows system.

Checking CLASSPATH on Unix, Linux or Mac

To check CLASSPATH variable is set on Unix/Linux/Mac run following command on shell
$ echo $CLASSPATH

If CLASSPATH variable is not set you will see CLASSPATH: Undefined variable error on Unix/Linux/Mac systems.

How to set Multiple Jar Files in Java Classpath

Java versions Older then Java 6 does not support wildcard characters. Setting Multiple jars using wildcard in Java classpath are allowed in Java 6 and later versions.

For example, to specify all jar files in a directory “lib” the classpath entry should look like this lib/*

The wildcard entry (*) in classpath value will match only jar files NOT class files. To match both class files and JAR files in a same directory lib, you need to specify both values as shown below

Setting Multiple Jars in Classpath on Windows

Windows environment variable values are separated by semicolon, therefore you classpath entry would look like thislib/*;lib

Setting Multiple Jars in Classpath on Unix, Linux or Mac

Unix environment variable values are separated by colon, therefore you classpath entry would look like thislib/*:lib

Older version of Java

In older version of Java(older than Java 6), each jar file needs to be specified in the classpath. It can be a tedious and erroneous task if you are using many third party libraries.