How to Create String from Char Array in Java

In Java, you can create a String from a char array by passing the array to the String constructor like new String(charArray). This converts the array of characters into a readable string.

Syntax

The basic syntax to create a String from a char array is:

• new String(charArray): Creates a new string containing all characters from the array.
• new String(charArray, offset, count): Creates a string from a subset of the array starting at offset and using count characters.

java

char[] charArray = {'H', 'e', 'l', 'l', 'o'};
String str = new String(charArray);

char[] charArray2 = {'J', 'a', 'v', 'a', ' ', 'R', 'o', 'c', 'k', 's'};
String str2 = new String(charArray2, 5, 5);

Example

This example shows how to convert a full char array and a part of a char array into strings and print them.

java

public class CharArrayToString {
    public static void main(String[] args) {
        char[] fullArray = {'H', 'e', 'l', 'l', 'o'};
        String fullString = new String(fullArray);
        System.out.println(fullString);  // Prints: Hello

        char[] partialArray = {'J', 'a', 'v', 'a', ' ', 'R', 'o', 'c', 'k', 's'};
        String partialString = new String(partialArray, 5, 5);
        System.out.println(partialString);  // Prints: Rocks
    }
}

Output

Hello
Rocks

Common Pitfalls

Common mistakes include:

• Passing null instead of a valid char array, which causes a NullPointerException.
• Using incorrect offset or count values that are out of bounds, causing StringIndexOutOfBoundsException.
• Trying to assign a char array directly to a String variable without using the constructor, which is not allowed.

java

char[] chars = {'a', 'b', 'c'};

// Wrong: This will cause a compile error
// String wrongString = chars;

// Correct:
String correctString = new String(chars);

// Wrong: Using invalid offset and count
// String errorString = new String(chars, 2, 5); // Throws exception

Quick Reference

Remember these key points when creating strings from char arrays:

• Use new String(charArray) for the whole array.
• Use new String(charArray, offset, count) for a part of the array.
• Check array bounds to avoid exceptions.

Key Takeaways

Use the String constructor with a char array to create a string: new String(charArray).

You can create a string from part of a char array using new String(charArray, offset, count).

Always ensure offset and count are within the array bounds to avoid errors.

You cannot assign a char array directly to a String variable without conversion.

Passing null as the char array will cause a NullPointerException.