MethodHandleExample.java

import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles.Lookup;

public class MethodHandleExample {
  private static final MethodHandle barGetter;
  private static final MethodHandle barSetter;
  
  static {
    Field barField = null;
    try {
      barField = FooClass.class.getDeclaredField("bar");
      
      barField.setAccessible(true); // Dunno if needed, but might as well
      
      barGetter = MethodHandles.lookup().unreflectGetter(barField);
      barSetter = MethodHandles.lookup().unreflectSetter(barField);
    } catch (Exception ex) {
      throw new RuntimeException(ex);
    }
  }
  
  public static void setBar(FooClass foo, Bar bar) {
    barSetter.invokeExact(foo, bar);
  }
  
  public static Bar getBar(FooClass foo) {
    return barGetter.invokeExact(foo);
  }
}