I keep getting null pointer exception when using classes when playing audio

Processing Libraries
1

So this is my main file (named Testing)

Minim minim;
Audio audio;

void setup()
{
  audio = new Audio();
  size(800, 800);
}



void draw()
{
  audio.drawShape();
  background(255);
  
}

And this is the Audio class file

import ddf.minim.*;
import ddf.minim.analysis.*;

class Audio
{
  final int BUFFERSIZE = 2048;
  AudioPlayer audio;
  Audio()
  {
    minim = new Minim(this);
    audio = minim.loadFile("audio.mp3", BUFFERSIZE);
    audio.play(); // This is where the nullpointer exception thing happens.
  }
  
  void drawShape()
  {
    ellipse(200, 400, audio.left.get(1)*800, audio.left.get(1)*800);
    ellipse(600, 400, audio.right.get(1)*800, audio.right.get(1)*800);
  }
  
}

I have the audio.mp3 in the same directory as these two files. But why do I keep getting this error message:

NullPointerException
Could not run the sketch (Target VM failed to initialize).
For more information, read revisions.txt and Help ? Troubleshooting.

Before I wasn’t getting it when I wasn’t uses classes, now all of a sudden why is this happening?