Using Bag in Java

Question

Here, I see that Bag class should be in java.util.Collection but when I try to use it, I get cannot be resolved to a type error.

Should I copy+pase this or is there some library missing?

Answer 1

Those are 2 different classes neither of which are part of the JDK. One is a custom class that needs to be added to the build path whereas the other is part of the Apache Commons library which need to be added to the classpath.