A quick guide on how to return arrays in java from methods for primitive, objects and multidimensional arrays.
1, Overview
In this tutorial, We'll learn how to return an array from a method in java.
If you are new to java programming, please refer to the article on How to initialize an array in java?
Thump rules:
- A method can return an array that is referencing another array.
- The return type of method must be declared as the correct array type.
2. Java Return Array from Method - int[] primitive array
In the below example, getNumbers() method returns an integer primitive type array.
Example 1:
package com.javaprogramto.arrays.returns;
import java.util.Arrays;
public class ArrayReturnExample1 {
public static void main(String[] args) {
int[] first5Numbers = getNumbers();
System.out.println("Array returned from method : " + Arrays.toString(first5Numbers));
}
// returning an array from method
public static int[] getNumbers() {
int[] numbers = { 1, 2, 3, 4, 5 };
return numbers;
}
}
Output:
Array returned from method : [1, 2, 3, 4, 5]
3. Java Return Array - double[] primitive & wrapper array
Below example returns a double[] array from the method.
Example 2:
package com.javaprogramto.arrays.returns;
import java.util.Arrays;
public class ArrayReturnExample2 {
public static void main(String[] args) {
double[] first5Numbers = getDoublePRimitive(5);
System.out.println("Double primitive Array returned from method : " + Arrays.toString(first5Numbers));
Double[] first6Numbers = getDoubleWrapper(5);
System.out.println("Double wrapper Array returned from method : " + Arrays.toString(first6Numbers));
}
// returning double primitive array from method
public static double[] getDoublePRimitive(int size) {
double[] numbers = new double[size];
for (int i = 0; i < size; i++) {
numbers[i] = i + 1;
}
return numbers;
}
// returning Double wrapper array from method
public static Double[] getDoubleWrapper(int size) {
Double[] numbers = new Double[size];
for (int i = 0; i < size; i++) {
numbers[i] = Double.valueOf(i + 1);
}
return numbers;
}
}
Output:
Double primitive Array returned from method : [1.0, 2.0, 3.0, 4.0, 5.0] Double wrapper Array returned from method : [1.0, 2.0, 3.0, 4.0, 5.0, 6.0]
4. Java Return Array - Custom Objects
Example 3:
package com.javaprogramto.arrays.returns;
import java.util.Arrays;
public class ArrayReturnExample3 {
public static void main(String[] args) {
CustomObject[] objects = getObjects();
System.out.println("Returned custom objects - " + Arrays.toString(objects));
}
// returning custom objects array from method
public static CustomObject[] getObjects() {
return new CustomObject[] { new CustomObject("Ram", 30), new CustomObject("Sita", 20) };
}
}
class CustomObject {
public String name;
public int age;
public CustomObject(String name, int age) {
this.age = age;
this.name = name;
}
@Override
public String toString() {
return "CustomObject [name=" + name + ", age=" + age + "]";
}
}
Output:
Returned custom objects - [CustomObject [name=Ram, age=30], CustomObject [name=Sita, age=20]]
5. Java Return Array - Multidimensional Array
Example 4:
package com.javaprogramto.arrays.returns;
import java.util.Arrays;
public class ArrayReturnExample4 {
public static void main(String[] args) {
int[][] multiArray = getMultiArray();
System.out.println("Returned Multi dimentional array values : ");
for(int[] a : multiArray) {
System.out.println( Arrays.toString(a));
}
}
// returning multi dimens
public static int[][] getMultiArray() {
int[][] multi = { { 1, 2, 3 }, { 4, 5, 6 } };
return multi;
}
}
Output:
Returned Multi dimentional array values : [1, 2, 3] [4, 5, 6]
6. Conclusion
In this article, we've seen how to return different types of arrays from a method in java.
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