double defaultSpeed = 1.8;
//Vector dir = player.getLocation().getDirection().multiply(defaultSpeed).setY(0.1);
Vector dir = player.getLocation().getDirection().setY(0); //player.getVelocity();
Vector veloc = player.getVelocity();
dir.setX(Math.max(Math.min((dir.getX() * defaultSpeed)+(veloc.getX()*0.3), 2), -2));
dir.setZ(Math.max(Math.min((dir.getZ() * defaultSpeed)+(veloc.getZ()*0.3), 2), -2));
dir.setY(veloc.getY());
player.setVelocity(dir);