Arrays vs. Java Lists
Explore the characteristics and uses of Java arrays and ArrayLists to understand their memory management, type safety, and dynamic resizing. Learn when to choose arrays for fixed-size, performance-critical tasks and ArrayLists for flexible, dynamic collections.
At this point, the concept of arrays is clear, including what they are, how indexing works, how they are stored in memory, and how size and dimensions affect their structure. The next step is learning how to work with arrays in Java.
Java has a built-in array type that is part of the core language. Unlike Python, which offers the array module and lists as separate options, Java provides native arrays directly. In this lesson, we will explore Java arrays and also look at ArrayList, Java's built-in dynamic list, and learn when to use each.
Java arrays
As we already know, a Java array is a true typed array that can only store elements of a single, fixed data type. Once we declare an array as an integer array, every element in it must be an integer. We cannot mix integers with strings, floats, or elements of any other data type. This is exactly what we meant when we described arrays as a collection of elements of the same type, stored in contiguous memory locations.
This homogeneous nature is not arbitrary. It is what allows the computer to store all elements directly in contiguous memory, calculate the address of any element instantly using the address formula, and process the data efficiently. Every slot in the array is ...