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•Created by Erky on 2/23/2025 in #java-help

How to sign executable jar with jsign or similar

So I have a game I want to share with a user who does not have Java. Im using launch4j to convert my .jar to .exe. I want to get rid of the antivirus warning. I found out I can do this by signing the application. I found out about Jsign for this. Is this a good idea?

43 replies

CC#

•Created by Erky on 2/19/2025 in #help

How to overwrite a file that is used by another process?

I know which process is locking it, its a .net host instance, but I still want to overwrite my .log file (i want to clear it, when i press a button). I keep getting System.IO.IOException: The process cannot access the file

10 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/20/2023 in #java-help

In game loop, reset index to 0, go through 4 animations, then do something

can someone help me to show* all 4 images of the dying animation before setting to gameover*? it works for setting game over in the player class but when I try to set game over when walking on a trap (lava), it only shows the first animationindex and I don't know how to correctly show all images of dying and then set game over Player

public void playerDeathAndGameOver() {
        if (playerAction != DYING) {
            playerAction = DYING;
            animationIndex = 0;
            animationTick = 0;
        }

        if (animationIndex == getSpriteAmount(DYING) - 1) {
            // here we reached final death animation shown, now set game over!
            game.setGameState(GAME_OVER);
        }
    }

public void playerDeathAndGameOver() {
        if (playerAction != DYING) {
            playerAction = DYING;
            animationIndex = 0;
            animationTick = 0;
        }

        if (animationIndex == getSpriteAmount(DYING) - 1) {
            // here we reached final death animation shown, now set game over!
            game.setGameState(GAME_OVER);
        }
    }

ObjectManager:

for (Lava l: lava)
            if (player.getHitbox().intersects(l.hitbox)) {
                player.setInLava(true);
                player.playerDeathAndGameOver();
                player.setInLava(false);
            }

for (Lava l: lava)
            if (player.getHitbox().intersects(l.hitbox)) {
                player.setInLava(true);
                player.playerDeathAndGameOver();
                player.setInLava(false);
            }

4 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/16/2023 in #java-help

How to increase jump height when holding space

I want the jump height to be depending on how long the player holds space. My question is how I can modify the airSpeed depending on the jumpTime (the time that player has held down space). Currently it's not adjusting jumpTime properly and I don't see how I can fix it. Here is my current implementation:

private void mainLoop() {
        if (jumping) {
            jumpTime++;
            if (inAir)
              return;
                inAir = true;
                canJump = false;

                // need to set airspeed depending on jump time here
                airSpeed -= jumpHeight;
            }
        }
    }

    // ====== Jumping ======
    private boolean jumping = false;
    private static final float MAX_JUMP_HEIGHT = 8.0f * SCALE;
    private static final float MIN_JUMP_HEIGHT = 4.0f * SCALE;
    private float jumpHeight = MIN_JUMP_HEIGHT;
    private float jumpTime = 0.0f;

public void keyPressed(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_SPACE) {
            player.setJumping(true);
            player.setJumpTime(0);
        }
    }

    public void keyReleased(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_SPACE) {
            player.setJumping(false);
            player.setCanJump(true);
        }
    }

private void mainLoop() {
        if (jumping) {
            jumpTime++;
            if (inAir)
              return;
                inAir = true;
                canJump = false;

                // need to set airspeed depending on jump time here
                airSpeed -= jumpHeight;
            }
        }
    }

    // ====== Jumping ======
    private boolean jumping = false;
    private static final float MAX_JUMP_HEIGHT = 8.0f * SCALE;
    private static final float MIN_JUMP_HEIGHT = 4.0f * SCALE;
    private float jumpHeight = MIN_JUMP_HEIGHT;
    private float jumpTime = 0.0f;

public void keyPressed(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_SPACE) {
            player.setJumping(true);
            player.setJumpTime(0);
        }
    }

    public void keyReleased(KeyEvent e) {
        if (e.getKeyCode() == KeyEvent.VK_SPACE) {
            player.setJumping(false);
            player.setCanJump(true);
        }
    }

4 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/16/2023 in #java-help

Disable autojump in game

is there a way to not allow autojump when holding space? i don't want autojump. problem is that when he lands, there is a split frame where inAir is false, so he is allowed to jump. it looks kinda buggy because you can autojump when standing still, or moving constant one direction, but not if you switch direction. here is the relevant code:

private void updatePos() {
        // Check if player is in air
        if (isEntityInAir(hitbox, level))
            inAir = true;

        // Player is in air; fall to the ground
        if (inAir)
            startFalling(level);

        // Player is jumping!
        if (jumping)
            jump();

public void jump() {
        inAir = true;
        airSpeed = -jumpHeight;
    }

protected void startFalling(Level level) {
        if (moveToPosition(hitbox.x, hitbox.y + airSpeed, hitbox.width, hitbox.height, level)) {
            // Set ySpeed
            airSpeed += GRAVITY;
        } else {
            // Cannot move to position -> Stop falling, reset jump height
            if (airSpeed > 0) {
                airSpeed = 0;
                inAir = false;
        }
    }

private void updatePos() {
        // Check if player is in air
        if (isEntityInAir(hitbox, level))
            inAir = true;

        // Player is in air; fall to the ground
        if (inAir)
            startFalling(level);

        // Player is jumping!
        if (jumping)
            jump();

public void jump() {
        inAir = true;
        airSpeed = -jumpHeight;
    }

protected void startFalling(Level level) {
        if (moveToPosition(hitbox.x, hitbox.y + airSpeed, hitbox.width, hitbox.height, level)) {
            // Set ySpeed
            airSpeed += GRAVITY;
        } else {
            // Cannot move to position -> Stop falling, reset jump height
            if (airSpeed > 0) {
                airSpeed = 0;
                inAir = false;
        }
    }

5 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/14/2023 in #java-help

Run jar file with JRE

I can't get to run a .jar file with JRE only. it only works with JDK 20

Exception in thread "main" java.lang.UnsupportedClassVersionError: misc/GameRunner has been compiled by a more recent version of the Java Runtime (class file version 63.0), this version of the Java Runtime only recognizes class file versions up to 52.0

I want to build a .exe with JRE bundled in but I can't even get JRE to run my application which was developed in JDK 20

11 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/10/2023 in #java-help

Not hearing sound in IntelliJ IDEA

import javafx.scene.media.AudioClip;
import java.io.File;

public class SoundPlayer {
    public static void main(String[] args) {
        File file = new File("res/audio/bg_music_playing.wav");
        AudioClip clip = new AudioClip(file.toURI().toString());
        clip.setVolume(3.00);
        clip.play();
    }
}

import javafx.scene.media.AudioClip;
import java.io.File;

public class SoundPlayer {
    public static void main(String[] args) {
        File file = new File("res/audio/bg_music_playing.wav");
        AudioClip clip = new AudioClip(file.toURI().toString());
        clip.setVolume(3.00);
        clip.play();
    }
}

simply not hearing anything, the audio file works fine and the program runs without issues but for some reason cannot hear anything

14 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/8/2023 in #java-help

I have a web app + database hosted in python which I have tested and works for creating, logging in and logging out user. Now I'm trying to make the requests in my android application written in java. However, I keep getting 308 error. Here is my RegisterActivity.java

private void register() {
        // Get headers, method and url to be used in the request
        final String user = username.getText().toString();
        final String pass = password.getText().toString();
        Map<String, String> userObject = new HashMap<>();
        userObject.put("username", user);
        userObject.put("password", pass);
        final int method = Request.Method.POST;
        final String url = "https://tddd80-app-joneri.azurewebsites.net/user";

        // Create request
        GsonRequest request = new GsonRequest(Request.Method.POST, url, userObject,
                response    -> System.out.println("Success! Response: " + response),
                error       -> System.out.println("Error with request: " + error.getMessage());

        // Add the request to the Volley request queue
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        requestQueue.add(request);

private void register() {
        // Get headers, method and url to be used in the request
        final String user = username.getText().toString();
        final String pass = password.getText().toString();
        Map<String, String> userObject = new HashMap<>();
        userObject.put("username", user);
        userObject.put("password", pass);
        final int method = Request.Method.POST;
        final String url = "https://tddd80-app-joneri.azurewebsites.net/user";

        // Create request
        GsonRequest request = new GsonRequest(Request.Method.POST, url, userObject,
                response    -> System.out.println("Success! Response: " + response),
                error       -> System.out.println("Error with request: " + error.getMessage());

        // Add the request to the Volley request queue
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        requestQueue.add(request);

and this is the most important part of GsonRequest which should parse JSON into string:

public class GsonRequest extends Request<String> {
    private final Map<String, String> headers;
    private final Response.Listener<String> listener;

    public GsonRequest(int method, String url, Map<String, String> headers,
                             Response.Listener<String> listener, Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        this.headers = headers;
        this.listener = listener;
    }

public class GsonRequest extends Request<String> {
    private final Map<String, String> headers;
    private final Response.Listener<String> listener;

    public GsonRequest(int method, String url, Map<String, String> headers,
                             Response.Listener<String> listener, Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        this.headers = headers;
        this.listener = listener;
    }

Any help is appreciated!

55 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/4/2023 in #java-help

Collision with slopes in a game

11 replies

JCHJava Community | Help. Code. Learn.

•Created by Erky on 4/3/2023 in #java-help

Java game slopes tile collision

I'm trying to figure out how I can make my player move on sloped tiles. My tiles all represent RGB values, and this is how I currently handle collisions and whether the player can move there or not:

// Go through all pixels in the level and add all data related to the level
for (int y = 0; y < img.getHeight(); y++)
    for (int x = 0; x < img.getWidth(); x++) {
    Color color     = new Color(img.getRGB(x, y));
    int red     = color.getRed();
    levelData[y][x] = red;

int tileValue = level.getLevelData()[tileY][tileX];
return switch (tileValue) {
    case TRANSPARENT_TILE, SLOPED_TILE -> false;
    default -> true;
    };

// Go through all pixels in the level and add all data related to the level
for (int y = 0; y < img.getHeight(); y++)
    for (int x = 0; x < img.getWidth(); x++) {
    Color color     = new Color(img.getRGB(x, y));
    int red     = color.getRed();
    levelData[y][x] = red;

int tileValue = level.getLevelData()[tileY][tileX];
return switch (tileValue) {
    case TRANSPARENT_TILE, SLOPED_TILE -> false;
    default -> true;
    };

And here I check if the tile is solid, and if so, the player can move to position and I update his hitbox.x (which is the top left position of the hitbox).

boolean isTopLeftSolid = isSolid(x, y, level);
boolean isTopRightSolid = isSolid(x + width, y, level);
boolean isBottomLeftSolid = isSolid(x, y+height, level);
boolean isBottomRightSolid = isSolid(x+width, y+height, level);

if (canMoveToPosition(hitbox.x + xDirection, hitbox.y, hitbox.width, hitbox.height, level))
    hitbox.x += xDirection;

boolean isTopLeftSolid = isSolid(x, y, level);
boolean isTopRightSolid = isSolid(x + width, y, level);
boolean isBottomLeftSolid = isSolid(x, y+height, level);
boolean isBottomRightSolid = isSolid(x+width, y+height, level);

if (canMoveToPosition(hitbox.x + xDirection, hitbox.y, hitbox.width, hitbox.height, level))
    hitbox.x += xDirection;

My question is, how can I adjust the player hitbox y position based on what section of a sloped tile he is standing on? I have the section of the tile he is standing on but I don't know how to update the "solidity" of a sloped tile.

boolean isTileSloped(int tileX, int tileY, Level level) {
    int tileValue = level.getLevelData()[tileY][tileX];

    if (tileValue != SLOPED_TILE)
        return false;

    float bottomLeft = hitbox.x / TILES_SIZE;
    int bottomLeftFloor = (int) Math.floor(bottomLeft);
    float difference = bottomLeft - bottomLeftFloor;
    int section = (int) (difference * 4) + 1;

    if (tileX == bottomLeftFloor) {
        System.out.println("Section " + section);
        if (section == 1) {
        // Need help here with setting the hitbox y position
        }
    }
    return true;
}

boolean isTileSloped(int tileX, int tileY, Level level) {
    int tileValue = level.getLevelData()[tileY][tileX];

    if (tileValue != SLOPED_TILE)
        return false;

    float bottomLeft = hitbox.x / TILES_SIZE;
    int bottomLeftFloor = (int) Math.floor(bottomLeft);
    float difference = bottomLeft - bottomLeftFloor;
    int section = (int) (difference * 4) + 1;

    if (tileX == bottomLeftFloor) {
        System.out.println("Section " + section);
        if (section == 1) {
        // Need help here with setting the hitbox y position
        }
    }
    return true;
}

92 replies

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