How can I check my classpath settings?

From the command line, the classpath is specified using the `-classpath` or `-cp` option. For example: `java -cp .:myjar.jar MyMainClass`. In an IDE, the classpath is managed through project settings. Verify that the classpath includes all necessary JAR files and directories. Incorrectly formatted classpath entries (e.g., missing colons or semicolons) can also cause problems.