How to detect if string contains emoji in Java?

I would like to detect if a string contains emoji in Java.

I tried https://github.com/vdurmont/emoji-java but it is not maintained anymore and fails on new emojis.

For example - the following test fails:

EmojiManager.containsEmoji("This string contains beans 🫘") shouldBe true

In Java 21 you will be able to use Character#isEmoji(int) to help you out.

<h3> How To: Detect Emojis in Strings </h3>

Since the emoji-java library can't be used in this case you have to go for java.lang.Character. In my code the containsEmoji(String str) method does the important work. Here we make use of Unicode rules and check them in the method. Character.SURROGATE indicates a Unicode surrogate pair, which Emojis use. Character.OTHER_SYMBOL includes various symbols including Emojis, but not limited to Emojis. In your case this code should be fine, however mind that other special symbols which are not Emojis in Unicode could trigger true too. Sadly I don't know any other way at the moment.

Fixed Code:

import java.lang.Character;
/**
* Main class for checking if String contains Emojis
*/
public class Main {
/**
* Main method to test Emoji Detector
*
* @param args are not used 
*/
public static void main(String[] args) {
String beans = "This string contains beans 🫘";
System.out.println("Does following String contain Emoji?");
System.out.println(beans);
System.out.println("Result: " + + containsEmoji(beans));
System.out.println("");
String smiley = "Hello, this is a happy message 😀";
System.out.println("Does following String contain Emoji?");
System.out.println(smiley);
System.out.println("Result: " + + containsEmoji(smiley));
System.out.println("");
String penguin = "There is a penguin here 🐧";
System.out.println("Does following String contain Emoji?");
System.out.println(penguin);
System.out.println("Result: " + + containsEmoji(penguin));
System.out.println("");
}
/**
* Checks if a String contains Emojis
*
* @param str is the parameter String to check
* @return True if String contains any Emojis, otherwise false
*/
private static boolean containsEmoji(String str) {
int length = str.length();
for (int i = 0; i < length; i++) {
int type = Character.getType(str.charAt(i));
if (type == Character.SURROGATE || type == Character.OTHER_SYMBOL) {
return true;
}
}
return false;
}
}

EDIT:
If you can use Java 21 (Older versions of Java don't support that) you can make use of the isEmoji() Method.

Here is an updated answer, including the resource you provided within the comments.

It should be able to mimic the containsEmoji method, although, it is not fully tested.

I used the following resource, Unicode, Annex A &ndash; Emoji Properties and Data Files.
Specifically, the emoji-data.txt data file.

I used the following regex to capture the values.

^([\dA-F]{4,5})(?:\.\.([\dA-F]{4,5}))?

And, a print value to compile the source.

list.add(new int[] { 0x$1, 0x$2 });\n

There will be several empty $2 groups, so you'll need to use a find-and-replace.

I cannot paste all the code, as it is over 30,000 characters.

public class EmojiUtil {
    static List<int[]> list = new ArrayList<>();

    static {
        /* https://unicode.org/Public/15.0.0/ucd/emoji/emoji-data.txt */
        list.add(new int[] { 0x0023 });
        list.add(new int[] { 0x002a });
        list.add(new int[] { 0x0030, 0x0039 });
        list.add(new int[] { 0x00a9 });
        list.add(new int[] { 0x00ae });
        list.add(new int[] { 0x203c });
        list.add(new int[] { 0x2049 });
        list.add(new int[] { 0x2122 });
        list.add(new int[] { 0x2139 });
        list.add(new int[] { 0x2194, 0x2199 });
        list.add(new int[] { 0x21a9, 0x21aa });
        list.add(new int[] { 0x231a, 0x231b });
        list.add(new int[] { 0x2328 });
        list.add(new int[] { 0x23cf });
        list.add(new int[] { 0x23e9, 0x23ec });
        list.add(new int[] { 0x23ed, 0x23ee });
        /* ... */
    }

    static boolean contains(String string) {
        char[] characters = string.toCharArray();
        char high, low;
        int index, limit;
        for (int[] values : list) {
            if (values.length == 1) limit = values[0];
            else limit = values[1];
            for (int codePoint = values[0]; codePoint <= limit; codePoint++) {
                if (codePoint > 0xffff) {
                    high = Character.highSurrogate(codePoint);
                    low = Character.lowSurrogate(codePoint);
                    if ((index = Arrays.binarySearch(characters, (char) high)) >= 0) {
                        if (index + 1 < characters.length && characters[index + 1] == (char) low)
                            return true;
                    }
                } else if (Arrays.binarySearch(characters, (char) values[0]) >= 0)
                    return true;
            }
        }
        return false;
    }
}

Example

EmojiUtil.contains("This string contains beans \uD83E\uDED8");