A benchmark for testing method handle performance.

MethodHandleTest.java

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;


public class MethodHandleTest
{
  private static final String METHOD_NAME = "increment";
  
  private static final int LOOPS = 1000000;
  
  static class Incrementer
  {
    long incrementedNumber;
    
    public void increment(String arg)
    {
      // just do something
      incrementedNumber += 1;
    }
  }

  public static void main(String[] args) throws Throwable
  {
    usingReflection();
    
    usingMethodHandles();
  }

  private static void usingReflection() throws NoSuchMethodException,
      IllegalAccessException, InvocationTargetException
  {
    Method method = Incrementer.class.getMethod(METHOD_NAME, String.class);
    
    long startTime = System.currentTimeMillis();
    Incrementer increments = new Incrementer();
    for (int i = 0; i < LOOPS; i++)
    {
      method.invoke(increments, "12345");
    }
    long elapsed = System.currentTimeMillis() - startTime;
    System.out.println("reflection took " + elapsed + "ms, result is " + increments.incrementedNumber);
  }

  private static void usingMethodHandles() throws NoSuchMethodException,
      IllegalAccessException, Throwable
  {
    MethodType methodType;
    MethodHandle methodHandle;
    MethodHandles.Lookup lookup = MethodHandles.lookup();
    
    methodType = MethodType.methodType(void.class, String.class);
    methodHandle = lookup.findVirtual(Incrementer.class, METHOD_NAME, methodType);

    long startTime = System.currentTimeMillis();
    
    Incrementer increments = new Incrementer();
    for (int i = 0; i < LOOPS; i++)
    {
       methodHandle.invokeExact(increments, "12345");
    }
    long elapsed = System.currentTimeMillis() - startTime;
    System.out.println("method handles took " + elapsed + "ms, result is " + increments.incrementedNumber);
  }
}