AP CSA Unit 4: Data Collections is the largest unit in the current College Board AP Computer Science A course framework. Use this page to organize your Unit 4 MCQ preparation topic by topic, from array creation and traversal through ArrayList, 2D arrays, searching, sorting, and recursion.
Important: This hub follows the current College Board topic numbering. Existing JavaTutorOnline practice pages are linked where they already provide relevant practice. Topics without dedicated practice are marked Coming Soon.
Data Collection & Arrays
The first part of Unit 4 introduces data collection issues and foundational array concepts, including creating arrays, accessing elements, traversing arrays, and implementing common array algorithms.
Ethical and Social Issues Around Data Collection
Explore considerations related to collecting, storing, using, and interpreting data in computing systems.
Coming SoonIntroduction to Using Data Sets
Practice interpreting and working with data sets as part of the current AP CSA Data Collections framework.
Coming SoonArray Creation and Access
Practice creating arrays, initializing array elements, accessing elements by index, and understanding array references and default values.
✓ Practice AvailableArray Traversals
Practice tracing traditional for loops and enhanced for loops when traversing arrays and processing their elements.
✓ Practice AvailableImplementing Array Algorithms
Practice common array-processing algorithms involving searching, counting, finding values, and modifying elements.
✓ Practice AvailableUsing Text Files
Practice reading and processing information from text files using the Java concepts included in the current AP CSA framework.
Coming SoonWrapper Classes
Practice Java wrapper classes, including the relationship between primitive values and their corresponding object types.
✓ Practice AvailableArrayList
Topics 4.8–4.10 focus on using ArrayList objects, traversing collections, and implementing algorithms that process ArrayList data.
ArrayList Methods
Practice the methods used to create, access, modify, and manage ArrayList collections.
Coming SoonArrayList Traversals
Practice tracing loops and other traversal techniques used to process elements stored in an ArrayList.
Coming SoonImplementing ArrayList Algorithms
Practice algorithms that search, count, modify, and process data stored in ArrayList objects.
Coming Soon2D Arrays
Topics 4.11–4.13 extend array concepts to two-dimensional structures and require careful tracing of rows, columns, nested loops, and array elements.
2D Array Creation and Access
Practice creating two-dimensional arrays and accessing elements using row and column indices.
Coming Soon2D Array Traversals
Practice nested-loop traversal of two-dimensional arrays, including row-by-row and column-based processing.
Coming SoonImplementing 2D Array Algorithms
Practice algorithms that process and modify values stored in two-dimensional arrays.
Coming SoonSearching & Sorting
Unit 4 also includes searching and sorting algorithms. Students should be able to trace algorithm behavior and understand the conditions required for algorithms such as binary search.
Searching Algorithms
Practice tracing linear and binary search algorithms and understanding how they locate values in collections.
Coming SoonSorting Algorithms
Practice tracing the sorting algorithms included in the current AP CSA framework.
Coming SoonRecursion
The final Unit 4 topics introduce recursive algorithms and recursive approaches to searching and sorting collections.
Recursion
Practice tracing recursive methods and understanding recursive processing of strings and collections.
Coming SoonRecursive Searching and Sorting
Practice recursive binary search and merge sort, including tracing recursive calls and collection changes.
Coming SoonUnit 4 Arrays Practice Assessment
AP CSA Arrays Practice Assessment
Practice questions covering the current Unit 4 array concepts, including array creation and access, array traversal, enhanced for loops, and common array algorithms.
Coverage note: This existing assessment currently focuses on Topics 4.3–4.5. It is useful for array practice but should not be treated as a comprehensive assessment of all Unit 4 topics.
AP CSA Unit 4 MCQ Practice FAQ
What is AP CSA Unit 4?
Unit 4 is called Data Collections in the current AP Computer Science A framework. It covers arrays, ArrayList, 2D arrays, searching, sorting, recursion, and related data-collection concepts.
How many topics are in AP CSA Unit 4?
The current College Board framework contains 17 Unit 4 topics, numbered 4.1 through 4.17.
What percentage of the AP CSA Exam is Unit 4?
Unit 4 has an official AP Exam weighting of 30–40% in the current College Board course framework.
Does Unit 4 include arrays and ArrayList?
Yes. Unit 4 includes one-dimensional arrays, ArrayList, two-dimensional arrays, and algorithms that operate on these collections.
Does Unit 4 include recursion?
Yes. Topics 4.16 and 4.17 cover recursion and recursive searching and sorting.
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