Does anyone know why I get this IndexOutOfBoundsExceptions error

Processing Coding Questions
1 
PFont font; 

ArrayList<walkers> l = new ArrayList<walkers>();
ArrayList<walkers> i = new ArrayList<walkers>();
ArrayList<walkers> L = new ArrayList<walkers>();

int mongolicos = 10;
int proteccion = 5;
int infectado_proteccion = 0;
int infectado_mongolico = 0;
int recuperados = 0;
int muertos = 0;

void setup() {
  size(500, 200);
  
font=loadFont("AgencyFB-Bold-48.vlw");
textFont(font);
  
  for (int j = 0; j < 10; j++) {
    l.add(new walkers('l'));
  }
    for (int n = 0; n < 5; n++) {
    l.add(new walkers('L'));
  }
  i.add(new walkers('i'));
}

void draw() {
  background(120);
 for (int n = 0; n < L.size(); n++) {
    L.get(n).dibujar();
    L.get(n).mover();
    L.get(n).detectarBordes();

for (int k = 0; k < L.size(); k++) {
      if (k != n) {
        L.get(n).interactuar(L.get(n), L.get(k));
      }

    if (i.size() > 0) {
      L.get(n).interactuar(L.get(n), i.get(0));
    }
    
    if (L.get(n).recovery_dead() == 'd') {
      L.remove(L.get(n));
      infectado_proteccion--;
      muertos++;
    }
}
}
  for (int j = 0; j < l.size(); j++) {
    l.get(j).dibujar();
    l.get(j).mover();
    l.get(j).detectarBordes();

    for (int k = 0; k < l.size(); k++) {
      if (k != j) {
        l.get(j).interactuar(l.get(j), l.get(k));
      }

    if (i.size() > 0) {
      l.get(j).interactuar(l.get(j), i.get(0));
    }
    
    if (l.get(j).recovery_dead() == 'd') {
      l.remove(l.get(j));
      infectado_mongolico--;
      muertos++;
    }
  }
}
  if (i.size() > 0) {
    i.get(0).dibujar();
    i.get(0).mover();
    i.get(0).detectarBordes();
    if (i.get(0).recovery_dead() == 'd') {
      i.remove(i.get(0));
      muertos++;
    }
  }
  fill(255);
  textSize(17);
  text("Sin Proteccion ="+mongolicos, 320,30);
    text("Con Proteccion ="+ proteccion, 320,70);
      text("Infectado_Sin Protección ="+ infectado_mongolico, 300,100);
      text("Infectado_Proteccion ="+ infectado_proteccion, 300,140);
      text("Recuperados ="+ recuperados, 320,170);
      text("Muertos="+muertos,320,200);
} 

class walkers {
  float h, k, d, vX, vY, time_i;
  char E;
  color Color;

  walkers(char estado) {
    d = 10;
    h = random(d / 2, width - (height + d / 2));
    k = random(d / 2, height - (d / 2));
    vX = random(-1.5, 1.5);
    vY = random(-1.5, 1.5);
    E = estado;

    if (E == 'l' || E == 'L') {
      Color = 255;
    } else if (E == 'i' || E == 'I') {
      Color = #E0663D;
    } else if (E == 'r') {
      Color = #4DD376;
      recuperados ++;
    }
  }

  walkers(float pX, float pY, float diameter, float velX, float velY, color C) {
    h = pX;
    k = pY;
    d = diameter;
    vX = velX;
    vY = velY;
    Color = C;
  }

  void dibujar() {
    if(E == 'L' || E == 'I'){
      noFill();
      stroke(200);
      ellipse(h, k, 3 * d / 2, 3 * d / 2);
      fill(Color);
      noStroke();
      ellipse(h,k,d,d);
    }  else if( E == 'l' || E == 'i'){
    fill(Color);
    noStroke();
    ellipse(h, k, d, d);
    }
  }

  void mover() {
    h += vX;
    k += vY;
    h = constrain(h, d / 2, width - (height + d / 2));
    k = constrain(k, d / 2, height - (d / 2));
  }

  void detectarBordes() {
    if (h + d / 2 >= width - height || h - d / 2 <= 0) {
      vX = -vX;
    } else if (k - d / 2 <= 0 || k + d / 2 >= height) {
      vY = -vY;
    }
  }

  void interactuar(walkers w1, walkers w2) {
    float w1VX = w1.vX;
    float w1VY = w1.vY;
    float w2VX = w2.vX;
    float w2VY = w2.vY;

    float R;

    if (dist(w1.h, w1.k, w2.h, w2.k) <= w1.d / 2 + w2.d / 2 //
     && ((w1.E == 'l' && w2.E == 'i')//
     || (w1.E == 'l' && w2.E == 'l')//
     || (w1.E == 'i' && w2.E == 'l')//
     || (w1.E == 'i' && w2.E == 'i'))) {
      w1.vX = w2VX;
      w1.vY = w2VY;
      w2.vX = w1VX;
      w2.vY = w1VY;

      R = random(100);

      if (w1.E == 'l' && w2.E == 'i' && R > 95) {
        w1.E = 'i';
        mongolicos --;
        infectado_mongolico++;
        w1.Color = #FA47E8;
        time_i = millis();
      }
    }else if ( dist (w1.h, w1.k, w2.h, w2.k) <= w1.d / 2 + 3 * w2.d / 4//
    && ((w1.E == 'l' && w2.E == 'L') //
    || (w1.E == 'i' && w2.E == 'L')//
    || (w1.E == 'l' && w2.E == 'I'))) {
      w1.vX = w2VX;
      w1.vY = w2VY;
      w2.vX = w1VX;
      w2.vY = w1VY;  
      
      R = random(100);
      if ((w1.E == 'i' && w2.E == 'L') || (w1.E == 'L' && w2.E == 'i')//
        && R < 0.02 ){
        w2.E = 'I';
        proteccion--;
        infectado_proteccion++;
        w2.Color = #FA47E8;
        time_i = millis();
       }
  }
  else if ( dist (w1.h, w1.k, w2.h, w2.k) <= 3 * w1.d / 4 + 3 * w2.d / 4//
    && ((w1.E == 'L' && w2.E == 'L') //
    || (w1.E == 'I' && w2.E == 'L')//
    || (w1.E == 'L' && w2.E == 'I')//
    || (w1.E == 'I' && w2.E == 'I'))) {
      w1.vX = w2VX;
      w1.vY = w2VY;
      w2.vX = w1VX;
      w2.vY = w1VY;  
      
      R = random(100);
      if (w1.E == 'L' && w2.E == 'I' && R > 0.05 ){
        w2.E = 'I';
        proteccion--;
        infectado_proteccion++;
        w2.Color = #FA47E8;
        time_i = millis();
       }
  }
  }

  char recovery_dead() {
    float R = random(100);
    if ((E == 'i'|| E == 'I') && millis() > time_i + 30000 && R > 0.09) {
      E = 'd';
      return E;
    } else if ((E == 'i'|| E == 'I' ) && millis() > time_i + 30000 && R > 10) {
      E = 'r';
      Color = #3DD85B;
      return E;
    }else {
      return ' ';
    }
  }
}
2

L is empty, you haven’t defined it in setup()