Answer by Chris Clark for How do I import jars into my java program?

You probably have the classpath stuff right. The class you're trying to import may not be called java.stdlib though. You need to import the fully qualified package name ... probably something like org.somecompany.ourlibrary.stdlib. Thus you would need

import org.somecompany.ourlibrary.stdlib

at the top of your Percolations.java file with the rest of the import statements.