java util Arrays Class - Arrays for manipulating arrays
java.util.Arrays Class
Arrays Class in Java
Java Arrays class contains various methods for manipulating arrays (such as sorting and searching). Java Arrays class contains a static factory that allows arrays to be viewed as lists. You need not to instantiate java.util.Arrays class because all the methods are static methods so that we can call the methods with the class name. The methods in this class all throw a NullPointerException if the specified array reference is null, except where noted.
In this tutorial you can learn about java.util.Arrays class and its examples. And also learn how to use java.util.Arrays class. Following example shows how to use int array with java.util.Arrays class.
How to use int array with java.util.Arrays class Example
/* How to use int array with java.util.Arrays class Example Save with file name ArraysExample.java */ import java.util.Arrays; public class ArraysExample { public static void main(String args[]) { // int ARRAY DECLARATION AND CREATION int arr[] = {0,-5,2,5,-1,-4,-3,-2,3,1,4}; // int ARRAY OUTPUT AS STRING System.out.println(Arrays.toString(arr)); // int ARRAY SORTING Arrays.sort(arr); // int ARRAY OUTPUT AS STRING AFTER SORTING System.out.println("After Sorting"); System.out.println(Arrays.toString(arr)); // SEARCHING IN int ARRAY int index = Arrays.binarySearch(arr, 3); if( index >= 0 ) System.out.println("3 is Found at Index : " + index); else System.out.println("3 is NOT Found"); // FILLING int ARRAY WITH DEFAULT ZERO Arrays.fill(arr,0); // int ARRAY OUTPUT AFTER FILL System.out.println(Arrays.toString(arr)); } }
Following example shows how to use double array with java.util.Arrays class.
How to use double array with java.util.Arrays class
/* How to use double array with java.util.Arrays class Save with file name ArraysExample2.java */ import java.util.Arrays; public class ArraysExample2 { public static void main(String args[]) { // double ARRAY DECLARATION AND CREATION double arr[] = {0.0,-5.0,2.0,5.0,-1.5,-4.0,-3.0,-2.0,3.0,1.5,4.0}; // double ARRAY OUTPUT AS STRING System.out.println(Arrays.toString(arr)); // double ARRAY SORTING Arrays.sort(arr); // double ARRAY OUTPUT AS STRING AFTER SORTING System.out.println("After Sorting"); System.out.println(Arrays.toString(arr)); // SEARCHING IN double ARRAY int index = Arrays.binarySearch(arr, 3); if( index >= 0 ) System.out.println("3 is Found at Index : " + index); else System.out.println("3 is NOT Found"); // FILLING double ARRAY WITH DEFAULT ZERO Arrays.fill(arr,0); // double ARRAY OUTPUT AFTER FILL System.out.println(Arrays.toString(arr)); } }
Note : When filling an object array, the fill() method will copy the same object reference to every cell in the array. After filling the array, if you then change that one reference, the attributes of the object in every cell in the array will be changed.
Following example shows how to use String array with java.util.Arrays class.
How to use String array with java.util.Arrays class
/* How to use String array with java.util.Arrays class Save with file name ArraysExample3.java */ import java.util.Arrays; import java.util.Collections; public class ArraysExample3 { public static void main(String args[]) { // String ARRAY DECLARATION AND CREATION String arr[] = {"Java Tutorials","NetBeans Tutorials","Huda Tutorials","C"}; // String ARRAY OUTPUT AS STRING for(int i=0;i<arr.length; i++) { System.out.println(arr[i]); } // String ARRAY SORTING Arrays.sort(arr); // String ARRAY OUTPUT AS STRING AFTER SORTING System.out.println("\nAfter Sorting\n"); for(int i=0;i<arr.length; i++) { System.out.println(arr[i]); } // SEARCHING IN String ARRAY int index = Arrays.binarySearch(arr, "Huda Tutorials"); if( index >= 0 ) System.out.println("\nHuda Tutorials is Found at Index : " + index); else System.out.println("\nHuda Tutorials is NOT Found"); // String ARRAY REVERSE ORDER Arrays.sort(arr,Collections.reverseOrder()); // String ARRAY OUTPUT AS STRING AFTER SORTING System.out.println("\nAfter Reverse Order\n"); for(int i=0;i<arr.length; i++) { System.out.println(arr[i]); } // FILLING String ARRAY WITH DEFAULT null Arrays.fill(arr,null); // String ARRAY OUTPUT AFTER FILL System.out.println(Arrays.toString(arr)); } }