The Salesforce Certified Platform Developer II credential is designed for those who can demonstrate their skills and knowledge in advanced programmatic capabilities of the Force.com platform and data modeling to develop complex business logic and interfaces.

Here are some examples of the concepts you should understand to pass the exam:

  • Design, develop, test, and deploy programmatic solutions that are maintainable and re-usable
  • Follow Apex design patterns and object-oriented programming best practices

Reference