Java Arrays Class with Examples

Arrays Class in Java

Last Updated: 28 May, 2022

Arrays is a utility class in Java, It was introduced in JDK 1.2 version and is available in java.util package. Arrays class is a member of the Java Collections Framework.

Arrays class provides various methods for manipulating arrays such as sorting, searching and comparing, etc. All the methods of the Arrays class are static so we can access any method with the Arrays class name, It also contains Object class methods.

The methods of the Arrays class throw a NullPointerException if the specified array reference is null.

Declaration of Arrays Class

public class Arrays extends Object

Arrays Class provides following Methods:

Method	Description
List<T> asList(T[] arr)	Returns a fixed-size list backed by the specified Arrays.
int binarySearch(T[] arr, element)	Searches for the specified element in the array with the help of Binary Search algorithm, and returns the position.
int binarySearch(T[] arr, int fromIndex, int toIndex, T key, Comparator c)	Searches a range of the specified array for the specified object using the binary search algorithm.
T[] copyOf(T[] originalArr, int newLength)	Copies the specified array, truncating or padding with the default value (if necessary) so the copy has the specified length.
T[] copyOfRange(T[] originalArr, int fromIndex, int endIndex)	Copies the specified range of the specified array into a new Arrays.
boolean equals(T[] arr1, T[] arr2)	Returns true if the two specified arrays of booleans are equal to one another, otherwise retruns false.
boolean deepEquals(T[] arr1, T[] arr2)	Returns true if the two specified arrays of booleans are deeply equal to one another, otherwise retruns false (it compares including nested arrays).
int hashCode(T[] arr)	Returns the hash code for the specified array.
int deepHashCode(T[] arr)	Returns the hash code for the specified array including nested arrays.
String toString(T[] arr)	Returns a string representation of the contents of the specified array.
String deepToString(T[] arr)	Returns a string representation of the contents of the specified array including nested arrays.
void fill(T[] arr, T value)	Assigns the specified value to each element of the specified array.
void fill(T[] arr, int fromIndex, int toIndex, T value)	Assigns the specified value to each element of the specified range of the specified array. The range to be filled extends from fromIndex, inclusive, to toIndex, exclusive.
void parallelPrefix(T[] arr, BinaryOperator o)	Cumulates, in parallel, each element of the given array in place, using the supplied function.
void setAll(T[] arr, FunctionGenerator)	Sets all elements of the specified array, using the provided generator function to compute each element.
void parallelSetAll(T[] arr, FunctionGenerator)	Sets all elements of the specified array, in parallel, using the provided generator function to compute each element.
void sort(T[] arr)	Sorts the specified array into ascending order.
void parallelSort(T[] arr)	Sorts the specified array of objects into ascending order, according to the natural ordering of its elements.
Of<T> spliterator(T[] arr)	Returns a Spliterator.Of<T> covering all of the specified array.
Stream<T> stream(T[] arr)	Returns a sequential Stream with the specified array as its source.

Arrays Class Methods Example

  import java.util.Arrays;
  import java.util.List;
  public class ArraysExample1 {
    public static void main(String[] args) {
      
      // Creating an array
      String colors[] = new String[] {"Red", "Green", "Yellow", "Blue", "Gray"};
      
      // Converting array to list using asList() method
      List list = Arrays.asList(colors);
      
      // Printing the list
      System.out.println("List elements: " + list);
      
      // Using binary search algorithm search the specified element from specified array
      System.out.println("Index No: " + Arrays.binarySearch(colors, "Yellow"));
      
      // Sorts the array of elements into ascending order
      Arrays.sort(colors);
      
      // Printing the sorted array
      for(String str : colors)
      System.out.println(str);
    }
  }

List elements: [Red, Green, Yellow, Blue, Gray]
Index No: 2
Blue
Gray
Green
Red
Yellow

  import java.util.Arrays;
  public class ArraysExample2 {
    public static void main(String[] args) {
      
      // Creating first array of integer
      int intArray1[] = { 10, 20, 30, 40, 50 };
      
      // Creating second array of integer
      int intArray2[] = { 50, 40, 30, 20, 10 };
      
      // Comparing both arrays using Arrays.compare() method
      System.out.println("Arrays.compare(): " + Arrays.compare(intArray1, intArray2));
      
      // Comparing both arrays using Arrays.compareUnsigned() method
      System.out.println("Arrays.compareUnsigned: " + Arrays.compareUnsigned(intArray1, intArray2));
    }
  }

Arrays Class - Interview Questions and Answers

Why Arrays class is needed in Java Programming?

Arrays is a utility class in Java, It provides various methods for manipulating arrays such as sorting, searching, comparing, etc. but without these methods, suppose if we have to perform any operation such as sorting the array then we need to write the code for sorting which will increase the development task.

Arrays Class in Java

Arrays Class Methods Example

Arrays Class - Interview Questions and Answers

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