What is the Difference Between Arrays and Arraylists?
🆚 Go to Comparative Table 🆚The main differences between arrays and ArrayLists in Java are:
- Fixed vs. Dynamic Size: Arrays have a fixed size, meaning their size cannot be changed once they are created. On the other hand, ArrayLists are dynamic and allow elements to be added or removed after initialization.
- Data Types: Arrays can store both primitive data types (like int, char) and objects. ArrayLists can only store objects and use generics for type-safety.
- Resizable: Arrays are not resizable, while ArrayLists are resizable and can change their size after being created.
- Access Methods: Array members can be accessed using [], while ArrayList has a set of methods to access elements and modify them.
- Functionality: Arrays are basic functionality in Java, whereas ArrayLists are a part of the collection framework.
- Index-Based Operations: Functions such as indexOf() and remove() are not supported by arrays, while they are supported by ArrayLists.
- Memory Location: Arrays have contiguous memory locations, whereas ArrayLists store elements in a non-contiguous manner.
- Performance: Arrays are generally faster than ArrayLists due to their static behavior, while ArrayLists are slower because of their dynamic behavior.
In summary, arrays are typically used for storing elements of the same data type in a fixed-size sequence, while ArrayLists are more flexible and can change their size dynamically, making them suitable for a wider range of use cases.
Comparative Table: Arrays vs Arraylists
Here is a table comparing the differences between arrays and ArrayLists in Java:
| Feature | Array | ArrayList |
|---|---|---|
| Size | Fixed-size data structure, cannot change size once created | Variable-size data structure, can change size dynamically |
| Memory Location | Contiguous memory location for all elements | Non-contiguous memory location for elements, references stored in contiguous locations |
| Access | Elements accessed using [] operator | Elements accessed using methods like get(), set(), add(), remove(), etc. |
| Dimensionality | Can be single-dimensional or multidimensional | Can only be single-dimensional |
| Primitive Types | Can be created for primitive data types | Can only be created for non-primitive (reference) data types |
| Additional Methods | No additional methods like indexOf(), remove(), etc. | Supports additional methods like indexOf(), remove(), etc. |
| Performance | Better performance due to contiguous memory allocation | Slower performance due to resizing operations and non-contiguous memory allocation |
Arrays are fixed-size data structures, and their size cannot be changed once they are created. They can be single-dimensional or multidimensional and can be created for both primitive and non-primitive data types. ArrayLists, on the other hand, are variable-size data structures that can change size dynamically. They are part of the Java Collections framework and are single-dimensional. While arrays have a contiguous memory location for all elements, ArrayList elements have non-contiguous memory locations. ArrayLists also support additional methods like indexOf() and remove().
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