Check if a String contains a special character

To check if a String contains a special character in Java, you can use a regular expression to match any character that is not a letter or a digit. Here is an example of how to do this:

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import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class SpecialCharacterExample {

    public static void main(String[] args) {
        String input = "Hello World!";
        Pattern p = Pattern.compile("[^a-zA-Z0-9]");
        Matcher m = p.matcher(input);
        boolean containsSpecialCharacter = m.find();
        System.out.println(containsSpecialCharacter);
    }

}

This example uses the Pattern and Matcher classes from the java.util.regex package to check if the input string contains any characters that are not letters or digits. The regular expression [^a-zA-Z0-9] matches any character that is not a letter or a digit. The find() method returns true if the input string contains any characters that match the regular expression.

I hope this helps. Let me know if you have any questions.