Welcome to the AP CSA Unit 6 Arrays Practice Hub. In Java, a 1D array is a data structure used to store a fixed-size sequential collection of elements of the same type. Mastering arrays is arguably the most critical turning point in the AP Computer Science A curriculum, as they form the foundation for searching, sorting, and eventually ArrayLists (Unit 7) and 2D Arrays (Unit 8).

According to the College Board, Unit 6 accounts for 10–15% of your total exam score. However, array logic is heavily embedded in the Free Response Questions (FRQs), meaning its true weight is actually much higher.

What You Need to Know for the Exam:

• How to instantiate arrays and understand default values in memory.
• The difference between accessing elements and manipulating the array index.
• How to avoid ArrayIndexOutOfBoundsException runtime errors.
• When to use standard for loops versus enhanced for-each loops.
• Standard algorithms, including finding minimums/maximums, shifting, and reversing data.

Select a specific topic below to launch the interactive practice widget. We recommend completing them in order, finishing with the comprehensive Mock Exam.