Two ways :
First :
CTRL+shift+F and search for "com.google.guava". This will give you all the files where classes from this package has been imported.
Second :
Remove the dependency from pom.xml. And reload your pom changes.
This will remove your library from classpath. As soon as this happens, your IDE will start showing red lines under all the classes where your dependency has been used as it'll not find classes from your library mentioned in imports.
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