Java Arrays stream(T[] a)Method

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Description

The Java Arrays stream(T[] a) method returns a Stream covering all of the specified array.

Declaration

Following is the declaration for java.util.Arrays.stream(T[] a) method

public static <T> Stream<T> stream​(T[] array)

Type Parameters

T − This is the type of elements.

Parameters

a − This is the array, assumed to be unmodified during use.

Return Value

This method returns a stream for the array elements.

Exception

NA

Java Arrays stream​(T[] a, int fromIndex, int toIndex) Method

Description

The Java Arrays stream(T[] a, int fromIndex, int toIndex) method returns a Stream covering the specified range of the specified array.

Declaration

Following is the declaration for java.util.Arrays.stream(T[] a, int fromIndex, int toIndex) method

public static <T> Stream<T> stream​(T[] array, int fromIndex, int toIndex)

Parameters

• a − This is the array, assumed to be unmodified during use.

• fromIndex − This is the index of the first element, inclusive, to be covered.

• toIndex − This is the index of the last element, exclusive, to be covered

Return Value

This method returns a stream for the array elements.

Exception

• ArrayIndexOutOfBoundsException − if fromIndex < 0 or toIndex > array.length

Getting stream of Array of Objects Example

The following example shows the usage of Java Arrays stream(T[]) method. First, we've created an array of student objects. Using stream() method, array is printed thereafter.

package com.tutorialspoint;

import java.util.Arrays;

public class ArrayDemo {
   public static void main(String[] args) {
      // initialize array
      Student arr[] = { new Student(1, "Julie"), new Student(2, "Robert"), new Student(3, "Adam"), new Student(4, "Jene") };

      System.out.print("Array: [ ");

      // use the stream to print each item
      Arrays.stream(arr).forEach(i -> System.out.print(i + " "));
      
      System.out.print("]");
   }
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Array: [ [ 1, Julie ] [ 2, Robert ] [ 3, Adam ] [ 4, Jene ] ]

Getting stream of Array of Objects using Range Example

The following example shows the usage of Java Arrays stream(T[], int, int) method. First, we've created an array of student objects. Using stream() method, array is printed thereafter.

package com.tutorialspoint;

import java.util.Arrays;

public class ArrayDemo {
   public static void main(String[] args) {
      // initialize array
      Student arr[] = { new Student(1, "Julie"), new Student(2, "Robert"), new Student(3, "Adam"), new Student(4, "Jene") };

      System.out.print("Array: [ ");

      // use the stream to print each item
      Arrays.stream(arr, 0, arr.length).forEach(i -> System.out.print(i + " "));
      
      System.out.print("]");
   }
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Array: [ [ 1, Julie ] [ 2, Robert ] [ 3, Adam ] [ 4, Jene ] ]

Getting stream of Sub-Array of Objects Example

The following example shows the usage of Java Arrays stream(T[], int, int) method. First, we've created an array of student objects. Using stream() method, a sub-array is printed thereafter.

package com.tutorialspoint;

import java.util.Arrays;

public class ArrayDemo {
   public static void main(String[] args) {
      // initialize array
      Student arr[] = { new Student(1, "Julie"), new Student(2, "Robert"), new Student(3, "Adam"), new Student(4, "Jene") };

      System.out.print("Array: [ ");

      // use the stream to print each item
      Arrays.stream(arr, 0, 3).forEach(i -> System.out.print(i + " "));
      
      System.out.print("]");
   }
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Array: [ [ 1, Julie ] [ 2, Robert ] [ 3, Adam ] ]