Please help me check whether the following Java programming code is correct $,$ I hope to get a code with no error as a reference, thank you very much.

import greenfoot.$*$; $//$ Import the Greenfoot library

public class Bullet extends Actor $\{$

public Bullet$()\{$

setImage$("$bullet$.$png$")$; $//$ Set the image for the bullet

$\}$

public void act$()\{$

move$(6)$; $//$ Move the bullet to the right

checkCollision$()$;

if $($isAtEdge$())\{$

getWorld$().$removeObject$($this$)$; $//$ Remove the bullet if it goes out of bounds

$\}$

$\}$

private boolean isAtEdge$()\{$

$//$ Check if the bullet is out of the game area

if $($getX$()<0||$ getX$()>=$ getWorld$().$getWidth$()||$ getY$()<0||$ getY$()>=$ getWorld$().$getHeight$())\{$

return true;

$\}$

return false;

$\}$

private void checkCollision$()\{$

if $(!$getObjectsInRange$(20,$ Rock.class$).$isEmpty$())\{$

Rock rock $=($Rock$)$ getObjectsInRange$(20,$ Rock.class$).$get$(0)$;

getWorld$().$removeObject$($rock$)$; $//$ Remove the rock

getWorld$().$removeObject$($this$)$; $//$ Remove the bullet

return;

$\}$

$\}$

$\}$