the gravity ball is shaking, Is that because of the precision of float?

[ghost]

At some conditions, the ball won't finally 'stopped', actually it won't, I mean I can see it still shaking at the bottom of the window. Is that because of the precision of float? I have tried debugged it, only to find that it won't shaking if the speed is around +-0.0x

[ghost]

float x = 100;
float y = 0;

float speed = 0;
float gravity = 0.1;

void setup(){
size(200, 40);
}

void draw(){
background(255);

fill(0);
rectMode(CENTER);
ellipse(x, y, 10, 20);

y = y + speed;
speed = speed + gravity;

if( y > height ){
speed = speed * -0.3;//energy of motion lose.
//after collision, the reverse speed will slow.

y = height;

}

}

[ghost]

But in https://github.com/shiffman/LearningProcessing/tree/master/chp09_arrays/example_09_11_array_append
it won't, even changed the -0.95 to -0.6.