The 2018 AP Computer Science A Free Response problems are the last year to request a class that implements an interface.

The FrogSimulation method simulate must end the simulation when any of 3 conditions is met. The actual simulation is simple.

WordPairList requires implementing a constructor for a class with an ArrayList instance variable. This requires actually initializing the instance variable, not just adding values to it.

CodeWordChecker must correctly implement a simple interface. It must also use 2 simple String methods correctly.

In the ArrayTester method getColumn, it is easy to create an array of the wrong length. The isLatin method must correctly traverse both rows and columns (separately). It must also correctly use the helper methods.