How to call an instance of an object in a new class in an IDE?

I was wondering how I would be able to call an instance of a class from the main sketch in on of the classes i have created.

For example here how would I call the instance of WETriangleMesh "cave" in the new class meshpts. I have put notes where I am getting the error.

I have tried to run this in both IntelliJ and Eclipse but I can,t seem to figure it out.

Root Sketch

import processing.core.PApplet;
import peasy.*;
import toxi.geom.mesh.*;
import toxi.processing.ToxiclibsSupport;

public class MainApp extends PApplet {

    PeasyCam cam;
    ToxiclibsSupport gfx;
    WETriangleMesh cave;
    Meshpts pts;


    public static void main(String[] args){
        PApplet.main("MainApp", args);
    }

    public void settings(){
        size(1400, 800,P3D);
        smooth();
    }

    public void setup(){
        cam = new PeasyCam(this,750,750,0,2200);
        cave = (WETriangleMesh) new STLReader().loadBinary(sketchPath("data/"+"cave.stl"), STLReader.WEMESH);
        pts = new Meshpts(this);
        gfx=new ToxiclibsSupport(this);
    }

    public void draw(){
        background(0);


        stroke(255, 0, 0);
        noFill();

        cave.run();

        pushMatrix();
        fill(40, 120);
        noStroke();
        strokeWeight(1);
        stroke(10);
        lights();
        gfx.mesh(cave, false, 10);
        popMatrix();

    }
}

Class Meshpts

import processing.core.PApplet;


public class Meshpts{
    PApplet p;


    public Flock(PApplet p){
        this.p = p;
    }

    void run() {
        cave.computeCentroid(); // error is here
    }

}