Pasar un color RGB a Hexadecimal JAVA

public class RgbHex {

 public static void main(String[] args) {
  
   String[] num255 = new String[256];
   String[] hexa = {"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"};
   
   
  for(int i=0; i<=255;)
   {
   for(int j=0; j<=15; j++)
   {
    for(int k=0; k<=15; k++)
    {
     num255[i]=hexa[j]+hexa[k];
     i++;
    }
   }
   }
   
   
  /*Aqui probamos con 3 números cualquiera
   * de 255.
   */
  
 System.out.println("R:255 G:150 B:19 en Hexadecimal es:"
 +num255[255]+num255[150]+num255[19]);
 System.out.println("Puedes comprobar el color en: http://www.colorhexa.com/"
   +num255[255].toLowerCase()+num255[150].toLowerCase()+num255[19].toLowerCase());
}
}