Processing - Random Enemy Spawns

I am creating a game (using Processing 3.4) where I will need to spawn enemies in at random. I have created each different "type" of enemy in its own method in another class. In my main sketch I am trying to create a method that will randomly spawn one of the enemies periodically.

I am brand new to Processing, only started less then a week ago at Uni, but this was a little side project I wanted to complete to get a better understanding of Processing and Java.

Here is my current code;

From Main Sketch 1

void draw() {
  background(225);
  cursor(CROSS);
  score(); //calls score

  ///MAKE A FUNCTION SO THAT ENEMIES SPAWN RANDOMLY
  spawnEnemy();

  player.playerChar(); //calls playerChar from Player
  player.playerMovement(); //calls playerMovement from Player
}

From Main Sketch 2

void spawnEnemy() { //Create a method that when called spawns a random enemy.
  j = j+1;
  println(j);
  if (j == 180) {
    int enemyNumber = int(random(1, 6));
    println(enemyNumber);
    if (enemyNumber == 1) {
      enemy.redBar(enemy.enemyX, enemy.enemyY, enemy.xDist, enemy.yDist);
    }  
    if (enemyNumber == 2) {
      enemy.blueBar(enemy.enemyX, enemy.enemyY, enemy.xDist, enemy.yDist);
    }  
    if (enemyNumber == 3) {
      enemy.redBigCircle(enemy.enemyX, enemy.enemyY, enemy.circleRad);
      //circleCollision();
    } 
    if (enemyNumber == 4) {
      enemy.redBigCircle(enemy.enemyX, enemy.enemyY, enemy.circleRad);
      //circleCollision();
    }  
    if (enemyNumber == 5) {
      enemy.redSmallCircle(enemy.enemyX, enemy.enemyY, enemy.circleRad);
      //circleCollision();
    }  
    if (enemyNumber == 5) {
      enemy.blueSmallCircle(enemy.enemyX, enemy.enemyY, enemy.circleRad);
      //circleCollision();
    }
    enemy.enemyMovement();
    j=-1;
  }
}

From Class Enemy

Player playerCheck;

class Enemy {

  boolean redEnemy = false; // used to determine enemy colour
  color enemyColour = color(#B9B9E8); // sets default colour to blue

  float enemyX = width/2; // starting x coordinate //change to 0
  float enemyY = -400; // starting y coordinate //change to 0
  float xDist = width; // x distance for Bar
  float yDist = 75; // y distance for Bar
  float circleRad = 250; // radius for circles

  void enemyMovement() {
    enemyY = enemyY+5;
  }

  void redBar(float xPos, float yPos, float xDist, float yDist) {
    redEnemy = true;
    noStroke();
    enemyColour = color(#E38585);
    fill(enemyColour);
    rect(xPos, yPos, xDist, yDist);
  }

  void blueBar(float xPos, float yPos, float xDist, float yDist) {
    redEnemy = false;
    noStroke();
    enemyColour = color(#B9B9E8);
    fill(enemyColour);
    rect(xPos, yPos, xDist, yDist);
  }

  void redBigCircle(float xPos, float yPos, float rad) {

    redEnemy = true;
    noStroke();
    enemyColour = color(#E38585);
    fill(enemyColour);
    ellipse(xPos, yPos, rad*2, rad*2);
  }

  void blueBigCircle(float xPos, float yPos, float rad) {

    redEnemy = false;
    noStroke();
    enemyColour = color(#B9B9E8);
    fill(enemyColour);
    ellipse(xPos, yPos, rad*2, rad*2);
  }

  void redSmallCircle(float xPos, float yPos, float rad) {
    redEnemy = true;
    enemyColour = color(#E38585);
    fill(enemyColour);
    ellipse(width/2, height/2, rad, rad); //change xPos to 0
  }

  void blueSmallCircle(float xPos, float yPos, float rad) {
    redEnemy = false;
    enemyColour = color(#B9B9E8);
    fill(enemyColour);
    ellipse(xPos, yPos, rad, rad); //change xPos to 0
  }
}

I have another Class for my player movement but basically its just an ellipse that is positioned to wherever the cursor is.