Array and Collections are a fundamental concept in Java that plays an important role in data storage and manipulation. These are essential tools for any Java developer, providing the option to organize, store, and manage data efficiently.
Arrays in Java
An array is a fixed-size, homogenous data structure that stores elements of the same data type sequentially in memory. Each element in an array can be accessed using an index, which starts from 0 for the first element.
The main advantage of the array is we can represent more than one value by using a single variable, due to this readability of the Java code will be improved.
Limitations of Arrays
- The size of the array is fixed that is once we create an array there is no chance of increasing or decreasing the size of the array based on our requirement due to this to use arrays in Java, we should know the size in advance which may not be possible every time.
- Arrays can hold only homogenous data elements. we can use this problem by using an Object type array.
- Method support is not available for every requirement.
To overcome these problems of array we should go for collections concepts in Java.
Collections in Java
In comparison to arrays collections in Java are dynamic and can grow and shrink inside as needed. Collections belong to the Java Collections framework, a compressive set of interfaces and classes that provide various data structures or store and manipulate data efficiently.
Collections can hold both homogenous and heterogenous values.
Every collection class is implemented based on some standard data structure, hence for every requirment method support is available.
Difference between Arrays and Collections
| Arrays | Collections |
|---|---|
| 1. Arrays are fixed in size. | 1. Collections are dynamic. |
| 2. With respect to memory arrays are not recommended to use. | 2. With respect to memory arrays are recommended to use. |
| 3. With respect to performance arrays are recommended to use. | 3. With respect to performance collections are not recommended to use. |
| 4. Arrays can store only homogenous data type elements. | 4. Arrays can store both homogenous and heterogenous elements. |
| 5. Method support is not available for the array. | 5. Method support is available for collections. |
| 6. Arrays can store both primitives and Objects. | 6. Arrays can store only object type but not primitives |