Java Convert Array to String [Snippet]

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In this quick article, we’re going to look at different ways to convert an array of strings or integers to a string.

Using Arrays.toString() method

Arrays.toString() returns a string with the content of the input array. The new string created is a comma-delimited list of the array’s elements, surrounded with square brackets (“[]”):
// Using Arrays.toString()
    public static String convertArrayToString(String[] strArray) {
        return Arrays.toString(strArray);
    }
Output:
[one, two, three]

Using StringBuilder.append() method

Let's use StringBuilder.append() method to convert from Array to String:
 // using StringBuilder.append()
    public static String convertArrayToStringMethod(String[] strArray) {
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < strArray.length; i++) {
            stringBuilder.append(strArray[i]);
        }
        return stringBuilder.toString();
    }
Output:
onetwothree

Using String.join() method

Java 8 and above offers the String.join() method that produces a new string by joining elements and separating them with the specified delimiter, in our case just empty string:
 // Using String.join() method
    public static String convertArrayToStringUsingStreamAPI(String[] strArray) {
        String joinedString = String.join(" ", strArray);
        return joinedString;
    }
Output:
one two three

Using Collectors.joining() method from the Java Streams AP

 // Using Stream API and Collectors
    public static String convertArrayToStringUsingCollectors(String[] strArray) {
        String joinedString = Arrays.stream(strArray)
            .collect(Collectors.joining());

        return joinedString;
    }
Output:
onetwothree

Complete Example

package corejava;

import java.util.Arrays;
import java.util.stream.Collectors;

public class ArrayToStringConvertExample {
    public static void main(String[] args) {
        String[] strArray = {
            "one",
            "two",
            "three"
        };
        System.out.println(convertArrayToString(strArray));
        System.out.println(convertArrayToStringMethod(strArray));
        System.out.println(convertArrayToStringUsingStreamAPI(strArray));
        System.out.println(convertArrayToStringUsingCollectors(strArray));

        // convert string to array
        String[] strArray1 = "javaguides".split(" ");
    }

    // Using Arrays.toString()
    public static String convertArrayToString(String[] strArray) {
        return Arrays.toString(strArray);
    }

    // using StringBuilder.append()
    public static String convertArrayToStringMethod(String[] strArray) {
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < strArray.length; i++) {
            stringBuilder.append(strArray[i]);
        }
        return stringBuilder.toString();
    }

    // Using String.join() method
    public static String convertArrayToStringUsingStreamAPI(String[] strArray) {
        String joinedString = String.join(" ", strArray);
        return joinedString;
    }

    // Using Stream API and Collectors
    public static String convertArrayToStringUsingCollectors(String[] strArray) {
        String joinedString = Arrays.stream(strArray)
            .collect(Collectors.joining());

        return joinedString;
    }
}
Output:
[one, two, three]
onetwothree
one two three
onetwothree

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