Basic Understanding of Arrays in Java

Introduction to Java Arrays.

Normally, an array is a collection of similar type of elements which has
contiguous memory location.

Java array is an object which contains elements of a similar data type.
Additionally, the elements of an array are stored in a contiguous memory
location. It is a data structure where we store similar elements. We can
store only a fixed set of elements in a Java array.

Array in Java is index-based, the first element of the array is stored at the
0th index, 2nd element is stored on 1st index and so on.

Unlike C/C++, we can get the length of the array using the length
member. In C/C++, we need to use the size of operator.

In Java, array is an object of a dynamically generated class. Java array
inherits the Object class, and implements the Serializable as well as
Cloneable interfaces. We can store primitive values or objects in an array
in Java. Like C/C++, we can also create single dimensional or
multidimensional arrays in Java.

Moreover, Java provides the feature of anonymous arrays which is not
available in C/C++.




Advantages

o Code Optimization: It makes the code optimized, we can retrieve
or sort the data efficiently.
o Random access: We can get any data located at an index position.

Disadvantages

o Size Limit: We can store only the fixed size of elements in the
array. It doesn't grow its size at runtime. To solve this problem,
collection framework is used in Java which grows automatically.

, Types of Array in java
There are two types of array.

o Single Dimensional Array
o Multidimensional Array



Single Dimensional Array in Java
Syntax to Declare an Array in Java

1. dataType[] arr; (or)
2. dataType []arr; (or)
3. dataType arr[];

Instantiation of an Array in Java

1. arrayRefVar=new datatype[size];

Example of Java Array
Let's see the simple example of java array, where we are going to declare,
instantiate, initialize and traverse an array.

1. //Java Program to illustrate how to declare, instantiate, initialize
2. //and traverse the Java array.
3. class Testarray{
4. public static void main(String args[]){
5. int a[]=new int[5];//declaration and instantiation
6. a[0]=10;//initialization
7. a[1]=20;
8. a[2]=70;
9. a[3]=40;
10.a[4]=50;
11. //traversing array
12.for(int i=0 ;i<a.length ;i++)//length is the property of array
13. System.out.println(a[i]);
14.}}