Test various Java methods for extracting the first letter of a string, see http://stackoverflow.com/q/18201191/2514228

TestFirstLetterMethods.java

public class TestFirstLetterMethods{
  public static final int N_SIM = 1000;

  public static void main(String[] args){
    long method1 = 0;
    long method2 = 0;
    long method3 = 0;

    for (int i=0; i<N_SIM; i++){
      String example = "something";
      String firstLetter  = "";

      long l1=System.nanoTime();
      firstLetter = String.valueOf(example.charAt(0));
      method1 += System.nanoTime()-l1;
      
      long l2=System.nanoTime();
      firstLetter = example.substring(0, 1);
      method2 += System.nanoTime()-l2;

      long l3=System.nanoTime();
      firstLetter = Character.toString(example.charAt(0));
      method3 += System.nanoTime()-l3;
    }

    System.out.println("String.valueOf average: "+method1/N_SIM);
    System.out.println("example.substring average: "+method2/N_SIM);
    System.out.println("Character.toString average: "+method3/N_SIM);
  }
}