Home Java

Java Arrays

In Java, an array is a collection of variables with similar types that go by one common name. Arrays function differently in Java than they do in C/C++.
The following are a few key points regarding Java arrays.

All arrays are dynamically allocated in Java.
A contiguous memory location is used to store arrays.
A contiguous memory location is used to store arrays.
Java objects, such as arrays, have a property called length that can be used to determine their size. In C/C++, however, we use sizeof to determine length.

Table Of Content

Array in Java
Types of Array in java
Single Dimensional Array in java
Multidimensional Array in Java
Jagged Array in Java
Clone an array in Java
Arrays class in Java

Like other variables, a Java array variable can also be declared by adding [ ] after the data type.
The array's size cannot be changed (once initialized). An array reference can, however, be made to refer to another array.
This array storage enables us to access an array's elements at random.
The Java array also has other uses, such as static fields, local variables, and method parameters.
An array's size must be specified as an int or short value, not a long one.
Each of the ordered variables in the array has an index starting at 0.
Object is the superclass of an array type.
Every array type supports the Java.io.Serializable and Cloneable interfaces.

Types of Array in java

Single Dimensional Array
Multidimensional Array

Single Dimensional Array in java

Syntax to Declare an Array in Java

datatype [] array; // ex. int [] array;  
datatype array[]; // ex. int array[];   
datatype []array; // ex. int []array;

Initialization of Java Array

public class Main {
	public static void main(String[] args) {
		int array[]= {10,20,30};   //arrays declared and Initialized
	}
}

Example of Single Dimensional Array in java

 // Java example of Single Dimensional array

public class Main {
	public static void main(String[] args) {
		int array[]= {10,20,30};   //arrays declare and Initialized
		for(int i=0;i<array.length;i++){
			System.out.println(array[i]); 
		}	
	}
}

Output:

Array with for-each loop

Syntax of the for-each loop

for(datatype variable:array){  
    //body of the loop  
}

Example:

for (int i : array) {
	//body of the loop  
}

Java example of Array with for-each loop

 // Java example of array with for-each loop

public class Main {
	public static void main(String[] args) {
		int array[]= {10,20,30};   
		for (int arr : array) {
			System.out.println(arr); 
		}
	}
}

Output:

For Each loop Next »

Index Out Of Bounds Exception in Java

When traversing an array with a length that is negative, equal to, or greater than the array size, the Java Virtual Machine (JVM) throws an ArrayIndexOutOfBoundsException.

Java example of ArrayIndexOutOfBoundsException

 // Java example of ArrayIndexOutOfBoundsException

package HELLO;
public class Main {
	public static void main(String[] args) {
		int array[]= {10,20,30,40,50};   //arrays declare and Initialized
		for(int i=0;i<=5;i++){
			System.out.println(array[i]); 
		}
	}
}

Output:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 5 out of bounds for length 5
	at HELLO/HELLO.Main.main(Main.java:8)

How to Pass array to a Method in Java

Java example of Pass array to a Method in Java

 // Java example to find maximum of element of array

public class Main {	
	static void Maximum(int arr[]) {
		int max=arr[0];  
		for(int i=1;i<arr.length;i++){  
		 if(max<arr[i])  
			 max=arr[i];     
		 } 
		 System.out.println(max); 
    }
	public static void main(String[] args){
		int array[]= {10,20,30,40,50};    
		Maximum(array);
	}
}

Output:

How to returning array from the Method in Java

Java example of returning array from the Method in Java

 // Java example to returning Array from the Method

public class Main {	
	public static int[] array(){  
		int[] array={10,20,30,40};   
		return array;  
	} 
	public static void main(String args[])  {  
		int[] array=array();           
		for (int i = 0; i < array.length; i++) {
			System.out.print(array[i]+ " "); 
		}			    
	}  
}

Output:

Anonymous Array in Java

Since Java supports anonymous arrays, you don't need to declare an array when passing it to a method.

Java example of anonymous array

 // Java example of anonymous array

public class Main {	
	static void AnonymousArray(int array[]){  
	  for(int i=0;i<array.length;i++)  
	  System.out.println(array[i]);  
	}  	  
	public static void main(String args[]){  
		AnonymousArray(new int[]{10,20,30,40});//sending anonymous array to method  
	} 
}

Output:

Multidimensional Array in Java

Syntax to Declare an multidimensional Array in Java

datatype[][] array;  // e.g  int[][] array;  
datatype [][]array;  // e.g  int [][]array;  
datatype array[][];  // e.g  int array[][];    
datatype []array[];  // e.g  int []array[];

Initialization of Java Array

int[][] array=new int[2][3]; //2 row and 3 column

Example of Multidimensional Array in java

 // Java example of Multidimensional arrays

public class Main {	
	public static void main(String args[]){  
	  int[][] array={{10,20,30},{40,50,60},{70,80,90}};  
	  for(int i=0;i<array.length;i++){  
		  for(int j=0;j<array.length;j++){  
		    System.out.print(array[i][j]+" ");  
		  }  
		System.out.println();  
	 } 
   } 
}

Output:

10 20 30

40 50 60

70 80 90

Jagged Array in Java

A jagged array is an array of arrays where each member array can be of a different size, allowing us to create a 2-D array with variable numbers of columns in each row. These arrays are also referred to as Jagged arrays.

Example of Jagged Array in Java

 // Java example of Jagged Array

public class Main {	
	public static void main(String args[]){  
        // Declare a 2-D array with 3 rows
       int array[][] = new int[3][];
 
       //initialize and declare jagged array
 
       array[0] = new int[]{10,20,30};
       array[1] = new int[]{40,50,60,70};
       array[2] = new int[]{80,90,};
 
       // printing the jagged array
       System.out.println("Jagged Array:\n");
       for (int i=0; i<array.length; i++){
          for (int j=0; j<array[i].length; j++) {
        	  System.out.print(array[i][j] + " ");
           }
          System.out.println();
       }
   } 
}

Output:

Jagged Array:

40 50 60

40 50 60 70

80 90

How to Clone an array in Java

clone a single-dimensional array

We are able to clone the Java array because it implements the Cloneable interface. When a single-dimensional array is copied, a deep copy of the Java array is also created. This means that the actual value will be copied. However, when we copy a multidimensional array, it creates a shallow copy of the Java array, which means that the references are copied.

A "deep copy" is made when you clone a single-dimensional array, such as Object[], where the new array contains actual copies of the original array's elements rather than references.

Example of cloning of single-dimensional arrays in Java

 // Java example of cloning of single-dimensional arrays

public class Main {	
	public static void main(String args[]){  
     int array[] = { 10, 20, 30 };    
     int clonedArr[] = array.clone();
     // will display false because a deep copy for a one-dimensional array is created.
     System.out.println(array == clonedArr);
     // print array
     for (int i = 0; i < clonedArr.length; i++) {
        System.out.print(clonedArr[i] + " ");
     }
   } 
}

Output:

false

10 20 30

Clone of a multi-dimensional array

A clone of a multi-dimensional array (such as Object[][]) is a "shallow copy," which means it creates only a single new array with each element array referencing an original element array, but subarrays are shared.

Example of cloning of multi-dimensional arrays in Java

 // Java example of cloning of multi-dimensional arrays

public class Main {	
	public static void main(String args[]){  
        int array[][] = {{10,20,30}, {50,60}};     
        int cloneArr[][] = array.clone();
        System.out.println(array == cloneArr); //print false
        // will print true because shallow copy is used, which means that sub-arrays are shared
        System.out.println(array[0] == cloneArr[0]);
        System.out.println(array[1] == cloneArr[1]); 
   } 
}

Output:

false

true

true

Arrays class in Java

The Arrays class in the java.util package is a Java Collection Framework component. This class provides static methods for creating and accessing Java arrays dynamically. It only has static methods and methods from the Object class. The methods of this class can be accessed via the class name.

Syntax: Declaration of class

public class Arrays extends Object

Syntax: Arrays

Arrays. <method name> ;

There are a number of static methods in the Arrays class in the java.util package that may be used to fill, sort, search, etc. in arrays. Let's now talk about the methods of this class

Example of sort of arrays in Java

 // Java example of sorting of arrays

import java.util.Arrays;
public class Main {	
	public static void main(String args[]){  
        int array[] = {10, 20, 05, 02, 30};        
        Arrays.sort(array); // array sort        
        System.out.println("Sorted Array is : "+ Arrays.toString(array));
   } 
}

Output:

Sorted Array is : [2, 5, 10, 20, 30]

Java String Next »

« Perv Next »

Java Arrays

Types of Array in java

Single Dimensional Array in java

Syntax to Declare an Array in Java

Initialization of Java Array

Example of Single Dimensional Array in java

Example of Single Dimensional Array in java

Array with for-each loop

Syntax of the for-each loop

Example:

Java example of Array with for-each loop

Index Out Of Bounds Exception in Java

Java example of ArrayIndexOutOfBoundsException

How to Pass array to a Method in Java

Java example of Pass array to a Method in Java

How to returning array from the Method in Java

Java example of returning array from the Method in Java

Anonymous Array in Java

Java example of anonymous array

Multidimensional Array in Java

Syntax to Declare an multidimensional Array in Java

Initialization of Java Array

Example of Multidimensional Array in java

Example of Multidimensional Array in java

Jagged Array in Java

Example of Jagged Array in Java

How to Clone an array in Java

clone a single-dimensional array

Example of cloning of single-dimensional arrays in Java

Clone of a multi-dimensional array

Example of cloning of multi-dimensional arrays in Java

Arrays class in Java

Syntax: Declaration of class

Syntax: Arrays

Example of sort of arrays in Java

Post your comment

Useful Links

Contact Us

About DockerTpoint