This week's book giveaways are in the Cloud and AI/ML forums. We're giving away four copies each of Cloud Native Patterns and Natural Language Processing and have the authors on-line! See this thread and this one for details.
You can write web applications without an MVC framework, but that quickly becomes very painful if your web application does more than just respond to a few requests with simple data.
Spring solves many problems that you'll have to solve yourself if you use pure Java. You can't really compare the two, Spring just adds to Java. You'll have to check out the Spring website for all the features they add.