bullets.add(new Bullet(x + 15, y + 15, (float) Math.atan2(input.getMouseY() - 1 - (y + 16),input.getMouseX() - 1 - (x + 16)),"normal"));

+16 is half of the size of the main player
-1 for some reason
+15 for some other reason.

new Bullet(playerx+(plaayerwidth/2)-1,playery+(plaayerheight/2)-1, maths to work out direction, type fo bullet)

public Bullet(float posx, float posy, float direction, String type){
    this.posx = posx;
    this.posy = posy;
    this.type = type;
    this.direction = direction;

    thecircle = new Circle(posx, posy, 2);

}
moving:

posx += Math.cos(direction) * MainGameState.bulletspeed;
    posy += Math.sin(direction) * MainGameState.bulletspeed;
    thecircle.setLocation(posx, posy);