What is an Array in Java?

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Introduction
 

Array in java lives in a group of like-typed variables directed to by a common name. Arrays in Java function differently than they do in C/C++. 

Following are some significant facts about Java arrays. 

• In Java, all arrays are dynamically assigned.
• Arrays are kept in contiguous memory [consecutive memory locations].
• Since arrays are objects in Java, we can find their length by operating the object property length. This is distinct from C/C++, where we find length from size.
• A Java array variable can also be affirmed like other variables with [] after the data type.
• The variables in the array are mandated, and everyone has an index starting with 0.
• Java arrays can also be used as a static field, a local variable, or a method parameter.
• The size of an array must be prescribed by int or short value and not long.
• An array can comprise primitives (int, char, etc.) and object (or non-primitive) references of a class relying on the description of the array. In the case of primitive data types, the existing values are stored in contiguous memory locations. In the case of class objects, the existing objects are kept in a heap segment. 

Types of Array in Java

In Java, there are Two Types of Arrays:-

• Single-Dimensional Array
• Multi-Dimensional Array

1. Single-Dimensional Array

An array that has only one subscript or one dimension is called a single-dimensional array. It is merely a list of similar data type variables.

One dimensional array can be of either one row and multiple columns or multiple rows and one column. For example, a student's marks in five subjects demonstrate a single-dimensional array.

2. Multi-Dimensional Array

In not all cases, we execute a single-dimensional array. Sometimes, we are needed to build an array within an array. A multi-dimensional array is just an array of arrays that symbolizes multiple rows and columns. These arrays contain 2D, 3D, and nD types. 2D data like tables and matrices can be defined using this type of array.

To execute a multidimensional array, one uses two square brackets rather than one.

Our Learners Also Read: What are Java Operators? Types, Examples, and more

Array Methods in Java

• asList() -This array method returns to a fixed-size list backed by the specified Arrays.
• binarySearch() – This array method searches for the specified element in the array with the help of the Binary Search Algorithm.
• compare(array 1, array 2) – This array method compares two arrays passed as parameters lexicographically.
• equals(array1, array2) – This array method checks if both arrays are equal or not.
• toString(originalArray)  – This array method returns a string expression of the contents of this array. The string expression consists of a list of the array’s elements, enclosed in square brackets (“[]”). Adjacent elements are divided into characters, a comma obeyed by a space. Elements are inverted to strings by String.valueOf() function.
• sort(originalArray) – This array method sorts the complete array in ascending order. 
• hashCode(originalArray) – This array method returns an integer hashCode of this array instance.
• mismatch(array1, array2) – This array method finds and returns the index of the first unmatched element between the two specified arrays.

Conclusion

Arrays in Java are non-primitive data types that keep elements of the same data type in the memory. Arrays in Java can keep both primitive and non-primitive types of data in it.

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