// https://es.stackoverflow.com/q/69597/127
import java.util.regex.Matcher; 
import java.util.regex.Pattern;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String texto = "kdya"; 
		String regex = "^[kd]"; 
		Pattern pat  = Pattern.compile(regex); 
		Matcher mat  = pat.matcher(texto);
 
		if (mat.find())
		{
			System.out.println("El texto '" + texto + "' empieza con " + mat.group()); 
		}
		else
		{
			System.out.println("No coincide");
		}
	}
}

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