Exception in thread "main" java.lang.VerifyError: Bad local variable type
Exception Details:
  Location:
    com/tabjy/dining_philosophers/Chopstick.pickUp(Lcom/tabjy/dining_philosophers/Philosopher;J)Z @34: aload_0
  Reason:
    Type top (current frame, locals[0]) is not assignable to reference type
  Current Frame:
    bci: @34
    flags: { }
    locals: { top, top, top, top, 'com/tabjy/dining_philosophers/__JFREventChopstickPickUp' }
    stack: { }
  Bytecode:
    0000000: bb00 2a59 59b7 002b b600 2e3a 042a b400
    0000010: 1f20 b200 34b6 0038 9a00 0a03 1904 b600
    0000020: 3bac 2a2b b500 3d04 1904 b600 3bac     
  Stackmap Table:
    full_frame(@34,{Top,Top,Top,Top,Object[#42]},{})

	at com.tabjy.dining_philosophers.DiningPhilosophers.main(DiningPhilosophers.java:17)
 

  public boolean pickUp(com.tabjy.dining_philosophers.Philosopher, long) throws java.lang.InterruptedException;
    descriptor: (Lcom/tabjy/dining_philosophers/Philosopher;J)Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=4, locals=5, args_size=3
         0: new           #42                 // class com/tabjy/dining_philosophers/__JFREventChopstickPickUp
         3: dup
         4: dup
         5: invokespecial #43                 // Method com/tabjy/dining_philosophers/__JFREventChopstickPickUp."<init>":()V
         8: invokevirtual #46                 // Method com/tabjy/dining_philosophers/__JFREventChopstickPickUp.begin:()V
        11: astore        4
        13: aload_0
        14: getfield      #31                 // Field lock:Ljava/util/concurrent/locks/ReentrantLock;
        17: lload_2
        18: getstatic     #52                 // Field java/util/concurrent/TimeUnit.MILLISECONDS:Ljava/util/concurrent/TimeUnit;
        21: invokevirtual #56                 // Method java/util/concurrent/locks/ReentrantLock.tryLock:(JLjava/util/concurrent/TimeUnit;)Z
        24: ifne          34
        27: iconst_0
        28: aload         4
        30: invokevirtual #59                 // Method com/tabjy/dining_philosophers/__JFREventChopstickPickUp.commit:()V
        33: ireturn
        34: aload_0
        35: aload_1
        36: putfield      #61                 // Field pickedUpBy:Lcom/tabjy/dining_philosophers/Philosopher;
        39: iconst_1
        40: aload         4
        42: invokevirtual #59                 // Method com/tabjy/dining_philosophers/__JFREventChopstickPickUp.commit:()V
        45: ireturn
      StackMapTable: number_of_entries = 1
        frame_type = 255 /* full_frame */
          offset_delta = 34
          locals = [ top, top, top, top, class com/tabjy/dining_philosophers/__JFREventChopstickPickUp ]
          stack = []
      LineNumberTable:
        line 24: 13
        line 25: 27
        line 28: 34
        line 29: 39
      LocalVariableTable:
        Start  Length  Slot  Name   Signature
           13      33     0  this   Lcom/tabjy/dining_philosophers/Chopstick;
           13      33     1 philosopher   Lcom/tabjy/dining_philosophers/Philosopher;
           13      33     2 timeout   J
    Exceptions:
      throws java.lang.InterruptedException

public int echo(int arg) {
    if (arg > 42) {
        return 42;
    }
    return arg;
}