Java Error: 'The method nextLine() is undefined for the type Scanner'

This error message indicates that you're trying to use the method 'nextLine()' with an object of the type 'Scanner', but the 'Scanner' class doesn't have a method with that name.

To fix this error, make sure that you've correctly spelled the method name and that you're using it on an object that has the 'nextLine()' method. For example, if you have a 'Scanner' object named 'scanner', you can use the 'nextLine()' method like this:

String line = scanner.nextLine();

If you're still getting the error, it's possible that you haven't imported the 'Scanner' class correctly. Make sure that you have imported 'java.util.Scanner' at the beginning of your file.