В методе move второй блок if...
package com.javarush.games.moonlander;
public class Rocket extends GameObject {
private double speedY = 0;
private double boost = 0.05;
private double speedX = 0;
private double slowdown = boost / 10;
public Rocket(double x, double y) {
super(x, y, ShapeMatrix.ROCKET);
}
public void move(boolean isUpPressed, boolean isLeftPressed, boolean isRightPressed) {
if (isUpPressed) speedY -= boost;
else speedY += boost;
y += speedY;
if (!isLeftPressed && !isRightPressed) {
if (speedX > -slowdown && speedX < slowdown) {
speedX = 0;
x += speedX;
} else if (speedX > slowdown) {
speedX -= slowdown;
x += speedX;
} else if (speedX < -slowdown) {
speedX += slowdown;
x += speedX;
}
}
checkBorders();
}
private void checkBorders() {
if (x < 0) x = 0;
speedX = 0;
if ((x + width) > MoonLanderGame.WIDTH) x = MoonLanderGame.WIDTH - width;
speedX = 0;
if (y < 0) y = 0;
speedY = 0;
}
}