Program: 134141
Project: 134141
Buggy source:
public void progress(){
  progressCounter++;
  for (int i=0; i < tasks.size(); i++) {
    BukkitRunnable br=tasks.get(i);
    if (br instanceof FireComboStream) {
      FireComboStream fs=(FireComboStream)br;
      if (fs.isCancelled())       tasks.remove(fs);
    }
  }
  if (player.isDead() || !player.isOnline()) {
    remove();
    return;
  }
  if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (destination == null) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      Vector eyeDir=player.getEyeLocation().getDirection().normalize().multiply(range);
      destination=player.getEyeLocation().add(eyeDir);
      player.getWorld().playSound(player.getLocation(),Sound.HORSE_JUMP,0.5f,0f);
      player.getWorld().playSound(player.getLocation(),Sound.FIZZ,0.5f,1f);
      for (int i=-30; i <= 30; i+=5) {
        Vector vec=Methods.getDirection(player.getLocation(),destination.clone());
        vec=Methods.rotateXZ(vec,i);
        FireComboStream fs=new FireComboStream(this,vec,player.getLocation(),range,speed);
        fs.setSpread(0.2F);
        fs.setDensity(5);
        fs.setUseNewParticles(true);
        if (tasks.size() % 3 != 0)         fs.setCollides(false);
        fs.runTaskTimer(ProjectKorra.plugin,0,1L);
        tasks.add(fs);
        player.getWorld().playSound(player.getLocation(),Sound.FIRE_IGNITE,0.5f,1f);
      }
      currentLoc=((FireComboStream)tasks.get(0)).getLocation();
      for (      FireComboStream stream : tasks)       if (Methods.blockAbilities(player,abilitiesToBlock,stream.currentLoc,2))       stream.remove();
    }
 else     if (tasks.size() == 0) {
      remove();
      return;
    }
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (destination == null) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      destination=player.getEyeLocation().add(range,0,range);
      player.getWorld().playSound(player.getLocation(),Sound.FIZZ,0.5f,0.5f);
      for (int i=0; i <= 360; i+=5) {
        Vector vec=Methods.getDirection(player.getLocation(),destination.clone());
        vec=Methods.rotateXZ(vec,i - 180);
        vec.setY(0);
        FireComboStream fs=new FireComboStream(this,vec,player.getLocation().clone().add(0,1,0),range,speed);
        fs.setSpread(0.0F);
        fs.setDensity(1);
        fs.setUseNewParticles(true);
        if (tasks.size() % 10 != 0)         fs.setCollides(false);
        fs.runTaskTimer(ProjectKorra.plugin,0,1L);
        tasks.add(fs);
      }
    }
    if (tasks.size() == 0) {
      remove();
      return;
    }
    for (    FireComboStream stream : tasks)     if (Methods.isWithinShields(stream.getLocation()))     stream.remove();
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (System.currentTimeMillis() - time > 5000) {
      remove();
      return;
    }
 else     if (FireJet.instances.containsKey(player)) {
      if (firstTime) {
        if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
          remove();
          return;
        }
        bplayer.addCooldown("String_Node_Str",cooldown);
        firstTime=false;
        float spread=0F;
        ParticleEffect.LARGE_EXPLODE.display(player.getLocation(),spread,spread,spread,0,1);
        player.getWorld().playSound(player.getLocation(),Sound.EXPLODE,15,0F);
      }
      player.setVelocity(player.getVelocity().normalize().multiply(speed));
      FireComboStream fs=new FireComboStream(this,player.getVelocity().clone().multiply(-1),player.getLocation(),3,0.5);
      fs.setDensity(1);
      fs.setSpread(0.9F);
      fs.setUseNewParticles(true);
      fs.setCollides(false);
      fs.runTaskTimer(ProjectKorra.plugin,0,1L);
      tasks.add(fs);
    }
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (firstTime) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      firstTime=false;
    }
 else     if (System.currentTimeMillis() - time > 5000) {
      remove();
      return;
    }
 else     if (FireJet.instances.containsKey(player)) {
      direction=player.getVelocity().clone().multiply(-1);
      player.setVelocity(player.getVelocity().normalize().multiply(speed));
      FireComboStream fs=new FireComboStream(this,direction,player.getLocation(),5,1);
      fs.setDensity(8);
      fs.setSpread(1.0F);
      fs.setUseNewParticles(true);
      fs.setCollisionRadius(3);
      fs.setParticleEffect(ParticleEffect.LARGE_SMOKE);
      if (progressCounter % 5 != 0)       fs.setCollides(false);
      fs.runTaskTimer(ProjectKorra.plugin,0,1L);
      tasks.add(fs);
      if (progressCounter % 4 == 0)       player.getWorld().playSound(player.getLocation(),Sound.FIZZ,1,0F);
    }
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (currentLoc == null) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      origin=player.getLocation();
      currentLoc=Methods.getTopBlock(player.getLocation(),3,3).getLocation();
      if (currentLoc == null) {
        remove();
        return;
      }
      currentLoc=player.getLocation();
      direction=player.getEyeLocation().getDirection().clone().normalize();
      direction.setY(0);
    }
 else     if (currentLoc.distance(origin) > range) {
      remove();
      return;
    }
    Block topBlock=Methods.getTopBlock(currentLoc,2,-4);
    if (topBlock == null || (Methods.isWaterbendable(topBlock,player) && !Methods.isPlant(topBlock))) {
      remove();
      return;
    }
    if (topBlock.getType() == Material.FIRE || Methods.isPlant(topBlock))     topBlock=topBlock.getLocation().add(0,-1,0).getBlock();
    currentLoc.setY(topBlock.getY() + FIRE_WHEEL_STARTING_HEIGHT);
    FireComboStream fs=new FireComboStream(this,direction,currentLoc.clone().add(0,-1,0),5,1);
    fs.setDensity(0);
    fs.setSinglePoint(true);
    fs.setCollisionRadius(1.5);
    fs.setCollides(true);
    fs.runTaskTimer(ProjectKorra.plugin,0,1L);
    tasks.add(fs);
    for (double i=-180; i <= 180; i+=3) {
      Location tempLoc=currentLoc.clone();
      Vector newDir=direction.clone().multiply(FIRE_WHEEL_RADIUS * Math.cos(Math.toRadians(i)));
      tempLoc.add(newDir);
      tempLoc.setY(tempLoc.getY() + (FIRE_WHEEL_RADIUS * Math.sin(Math.toRadians(i))));
      ParticleEffect.FLAME.display(tempLoc,0,0,0,0,1);
    }
    currentLoc=currentLoc.add(direction.clone().multiply(speed));
    currentLoc.getWorld().playSound(currentLoc,Sound.FIRE,1,1);
    if (Methods.blockAbilities(player,abilitiesToBlock,currentLoc,2)) {
      remove();
      return;
    }
    ;
  }
  if (progressCounter % 3 == 0)   checkSafeZone();
}

Fixed version (ground truth):
public void progress(){
  progressCounter++;
  for (int i=0; i < tasks.size(); i++) {
    BukkitRunnable br=tasks.get(i);
    if (br instanceof FireComboStream) {
      FireComboStream fs=(FireComboStream)br;
      if (fs.isCancelled())       tasks.remove(fs);
    }
  }
  if (player.isDead() || !player.isOnline()) {
    remove();
    return;
  }
  if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (destination == null) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      Vector eyeDir=player.getEyeLocation().getDirection().normalize().multiply(range);
      destination=player.getEyeLocation().add(eyeDir);
      player.getWorld().playSound(player.getLocation(),Sound.HORSE_JUMP,0.5f,0f);
      player.getWorld().playSound(player.getLocation(),Sound.FIZZ,0.5f,1f);
      for (int i=-30; i <= 30; i+=5) {
        Vector vec=Methods.getDirection(player.getLocation(),destination.clone());
        vec=Methods.rotateXZ(vec,i);
        FireComboStream fs=new FireComboStream(this,vec,player.getLocation(),range,speed);
        fs.setSpread(0.2F);
        fs.setDensity(5);
        fs.setUseNewParticles(true);
        if (tasks.size() % 3 != 0)         fs.setCollides(false);
        fs.runTaskTimer(ProjectKorra.plugin,0,1L);
        tasks.add(fs);
        player.getWorld().playSound(player.getLocation(),Sound.FIRE_IGNITE,0.5f,1f);
      }
      currentLoc=((FireComboStream)tasks.get(0)).getLocation();
      for (      FireComboStream stream : tasks)       if (Methods.blockAbilities(player,abilitiesToBlock,stream.currentLoc,2))       stream.remove();
    }
 else     if (tasks.size() == 0) {
      remove();
      return;
    }
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (destination == null) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      destination=player.getEyeLocation().add(range,0,range);
      player.getWorld().playSound(player.getLocation(),Sound.FIZZ,0.5f,0.5f);
      for (int i=0; i <= 360; i+=5) {
        Vector vec=Methods.getDirection(player.getLocation(),destination.clone());
        vec=Methods.rotateXZ(vec,i - 180);
        vec.setY(0);
        FireComboStream fs=new FireComboStream(this,vec,player.getLocation().clone().add(0,1,0),range,speed);
        fs.setSpread(0.0F);
        fs.setDensity(1);
        fs.setUseNewParticles(true);
        if (tasks.size() % 10 != 0)         fs.setCollides(false);
        fs.runTaskTimer(ProjectKorra.plugin,0,1L);
        tasks.add(fs);
      }
    }
    if (tasks.size() == 0) {
      remove();
      return;
    }
    for (    FireComboStream stream : tasks)     if (Methods.isWithinShields(stream.getLocation()))     stream.remove();
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (System.currentTimeMillis() - time > 5000) {
      remove();
      return;
    }
 else     if (FireJet.instances.containsKey(player)) {
      if (firstTime) {
        if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
          remove();
          return;
        }
        bplayer.addCooldown("String_Node_Str",cooldown);
        firstTime=false;
        float spread=0F;
        ParticleEffect.LARGE_EXPLODE.display(player.getLocation(),spread,spread,spread,0,1);
        player.getWorld().playSound(player.getLocation(),Sound.EXPLODE,15,0F);
      }
      player.setVelocity(player.getVelocity().normalize().multiply(speed));
      FireComboStream fs=new FireComboStream(this,player.getVelocity().clone().multiply(-1),player.getLocation(),3,0.5);
      fs.setDensity(1);
      fs.setSpread(0.9F);
      fs.setUseNewParticles(true);
      fs.setCollides(false);
      fs.runTaskTimer(ProjectKorra.plugin,0,1L);
      tasks.add(fs);
    }
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (firstTime) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      firstTime=false;
    }
 else     if (System.currentTimeMillis() - time > 5000) {
      remove();
      return;
    }
 else     if (FireJet.instances.containsKey(player)) {
      direction=player.getVelocity().clone().multiply(-1);
      player.setVelocity(player.getVelocity().normalize().multiply(speed));
      FireComboStream fs=new FireComboStream(this,direction,player.getLocation(),5,1);
      fs.setDensity(8);
      fs.setSpread(1.0F);
      fs.setUseNewParticles(true);
      fs.setCollisionRadius(3);
      fs.setParticleEffect(ParticleEffect.LARGE_SMOKE);
      if (progressCounter % 5 != 0)       fs.setCollides(false);
      fs.runTaskTimer(ProjectKorra.plugin,0,1L);
      tasks.add(fs);
      if (progressCounter % 4 == 0)       player.getWorld().playSound(player.getLocation(),Sound.FIZZ,1,0F);
    }
  }
 else   if (ability.equalsIgnoreCase("String_Node_Str")) {
    if (currentLoc == null) {
      if (bplayer.isOnCooldown("String_Node_Str") && !AvatarState.isAvatarState(player)) {
        remove();
        return;
      }
      bplayer.addCooldown("String_Node_Str",cooldown);
      origin=player.getLocation();
      if (Methods.getTopBlock(player.getLocation(),3,3) == null) {
        remove();
        return;
      }
      currentLoc=player.getLocation();
      direction=player.getEyeLocation().getDirection().clone().normalize();
      direction.setY(0);
    }
 else     if (currentLoc.distance(origin) > range) {
      remove();
      return;
    }
    Block topBlock=Methods.getTopBlock(currentLoc,2,-4);
    if (topBlock == null || (Methods.isWaterbendable(topBlock,player) && !Methods.isPlant(topBlock))) {
      remove();
      return;
    }
    if (topBlock.getType() == Material.FIRE || Methods.isPlant(topBlock))     topBlock=topBlock.getLocation().add(0,-1,0).getBlock();
    currentLoc.setY(topBlock.getY() + FIRE_WHEEL_STARTING_HEIGHT);
    FireComboStream fs=new FireComboStream(this,direction,currentLoc.clone().add(0,-1,0),5,1);
    fs.setDensity(0);
    fs.setSinglePoint(true);
    fs.setCollisionRadius(1.5);
    fs.setCollides(true);
    fs.runTaskTimer(ProjectKorra.plugin,0,1L);
    tasks.add(fs);
    for (double i=-180; i <= 180; i+=3) {
      Location tempLoc=currentLoc.clone();
      Vector newDir=direction.clone().multiply(FIRE_WHEEL_RADIUS * Math.cos(Math.toRadians(i)));
      tempLoc.add(newDir);
      tempLoc.setY(tempLoc.getY() + (FIRE_WHEEL_RADIUS * Math.sin(Math.toRadians(i))));
      ParticleEffect.FLAME.display(tempLoc,0,0,0,0,1);
    }
    currentLoc=currentLoc.add(direction.clone().multiply(speed));
    currentLoc.getWorld().playSound(currentLoc,Sound.FIRE,1,1);
    if (Methods.blockAbilities(player,abilitiesToBlock,currentLoc,2)) {
      remove();
      return;
    }
    ;
  }
  if (progressCounter % 3 == 0)   checkSafeZone();
}