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Java Libgdx weird Error with Textures and Arraylists

I'm pretty much a beginner when it comes to game development, especially with Libgdx, so far I made it so I can load any .tmx map or save it, I'm probably going to try and see how procedurally generating terrains works but right now I'm getting this weird error when I delete a block (that block consists of a TiledMapTile and a box2d body), I'm deletting it and after the deletion I'm creating a smaller entity that will also be a body, that represents the block I just deleted, as a drop for the player, this is the error I'm getting when I click a block, it only happens after the first block is deleted, so, one block is deleted and a small entity is created, but if I try to do it a second time, the game breaks and this appears:
A fatal error has been detected by the Java Runtime Environment:
EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007ffb8ecd9f58, pid=6580, tid=0x0000000000002474
JRE version: Java(TM) SE Runtime Environment (8.0_121-b13) (build 1.8.0_121-b13)
Java VM: Java HotSpot(TM) 64-Bit Server VM (25.121-b13 mixed mode windows-amd64 compressed oops)
Problematic frame:
C [ntdll.dll+0x39f58]
Failed to write core dump. Minidumps are not enabled by default on client versions of Windows
An error report file with more information is saved as:
C:\Libgdx Projects Fedora\WINDOWS\Generator Test\core\assets\hs_err_pid6580.log
If you would like to submit a bug report, please visit:
http://bugreport.java.com/bugreport/crash.jsp
The crash happened outside the Java Virtual Machine in native code.
See problematic frame for where to report the bug.
[error occurred during error reporting , id 0xc0000005]
This is the error log:
http://pastebin.com/a8iUH8Rz
This is where I delete the blocks:
public void destroyTerrain( ArrayList<Block> terrain, ArrayList<BlockDrop> blockDropsList ) {
int x = Gdx.input.getX() / 32;
int y = ( Gdx.graphics.getHeight() - Gdx.input.getY() ) / 32;
Iterator<Block> iterator = terrain.iterator();
while ( iterator.hasNext() ) {
Block block = iterator.next();
if ( x == ( int ) block.getBody().getPosition().x && y == ( int ) block.getBody().getPosition().y ) {
PolygonShape shape = ( PolygonShape ) block.getBody().getFixtureList().get( 0 ).getShape();
world.destroyBody( block.getBody() );
iterator.remove();
TiledMapTileLayer.Cell cell = ( ( TiledMapTileLayer ) map.getLayers().get( 0 ) ).getCell( x, y );
Texture tex = cell.getTile().getTextureRegion().getTexture();
// this is where the error is happening, when I'm creating a second blockDrop
BlockDrop blockDrop = new BlockDrop( screen, x, y, shape.getRadius() * 16, shape.getRadius() * 16 );
blockDrop.setTexture( tex );
blockDropsList.add( blockDrop );
cell.setTile( null );
}
}
}
This is the BlockDrop class:
public class BlockDrop extends Entity {
public BlockDrop( PlayGame screen, int x, int y, float width, float height ) {
super( screen );
posX = x;
posY = y;
type = BodyDef.BodyType.DynamicBody;
density = 0.2f;
friction = 0.4f;
shape = new PolygonShape();
( ( PolygonShape ) shape ).setAsBox( width, height, new Vector2( ( x / 32 ) + width * 2, ( y / 32 ) + height * 2 ), 0 );
createBody();
}
}
And this is the Entity:
abstract public class Entity {
private PlayGame screen;
float posX, posY;
private Body body;
Shape shape;
BodyDef.BodyType type;
float density;
float friction;
SpriteBatch batch;
Sprite sprite;
Entity( PlayGame screen ) {
this.screen = screen;
batch = new SpriteBatch();
sprite = new Sprite();
}
void createBody( ) {
BodyDef bodyDef = new BodyDef();
bodyDef.type = type;
bodyDef.position.set( posX, posY );
body = screen.getWorld().createBody( bodyDef );
body.setUserData( this );
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = shape;
fixtureDef.density = density;
fixtureDef.friction = friction;
body.createFixture( fixtureDef );
dispose();
}
public void setTexture(Texture tex){
sprite.setTexture( tex );
}
public void render( ) {
sprite.setBounds( posX, posY, shape.getRadius(), shape.getRadius() );
batch.begin();
sprite.draw( batch );
batch.end();
}
public String toString( ) {
return getClass().getSimpleName();
}
public Body getBody( ) {
return body;
}
public void dispose( ) {
shape.dispose();
batch.dispose();
}
}
Any help would be greatly appreciated, it might just be a simple dumb thing and the code might be a mess right now, but I can't seem to get around this

This error usually happens when an object is being used after you disposed it.
You are using a shape that was disposed:
iterator.remove();
...
BlockDrop blockDrop = new BlockDrop( screen, x, y, shape.getRadius() * 16, shape.getRadius() * 16 );

It's better to create and remove physics body in separate loop.
Create List of item that you want to create and another list that you want to remove and also keep in mind that creation and deletion must be performed when physics World is unlocked.
private World physicsWorld;
if(!physicsWorld.isLocked()) {
removeBodyFromWorld();
addBodyIntoWorld();
}
In removeBodyFromWorld() method remove your desired entity and create new body in addBodyIntoWorld() method.

detectMultiScale parameters in OpenCV 2.4.8 , Java

I'm trying to detect faces from a video stream using OpenCV 2.4.8 with Java using detectMultiScale. When searching through the web I noticed two versions of it with different parameter lists. Like here:
detectMultiScale(image, faceDetections) in [here][1] and face_cascade.detectMultiScale( frame_gray, faces, 1.1, 2, 0|CV_HAAR_SCALE_IMAGE, Size(30, 30) )
When I used it inside my code it gives an error :
OpenCV Error: Bad flag (parameter or structure field) (Unrecognized or unsupported array type) in cvGetMat
When I debug the code I see that error occurs at line:
face_cascade.detectMultiScale(frame_gray, faces);
I'm confused with these two parameter method because in OpenCV documentation site they have only one method with seven parameters.
detectMultiScale(const Mat& image, vector<Rect>& objects, double scaleFactor=1.1, int minNeighbors=3, int flags=0, Size minSize=Size(), Size maxSize=Size())
Can anyone please describe what is this two parameter method and does it has any connection with the error in my code. Following is the code I was checking on:
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.highgui.Highgui;
import org.opencv.highgui.VideoCapture;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;
public class FaceDetectSVM {
/**
* #param args
*/
public static void main(String[] args) {
//load opencv native library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
CascadeClassifier face_cascade = new CascadeClassifier("haarcascade_frontalface_alt.xml");
CascadeClassifier eyes_cascade = new CascadeClassifier("haarcascade_eye.xml");
String window_name = "Capture - Face detection.jpg";
System.out.println("capture through camera "+Core.VERSION);
//load the face xml cascade
if(!face_cascade.load("haarcascade_frontalface_alt.xml"))
{
System.out.println("Error loading face cascade");
}
else
{
System.out.println("Success loading face cascade");
}
//load the eyes xml cascade
if(!eyes_cascade.load("haarcascade_eye.xml"))
{
System.out.println("Error loading eyes cascade");
}
else
{
System.out.println("Success loading eyes cascade");
}
//detect default camera
VideoCapture capture = new VideoCapture(0);
if(!capture.isOpened())
{
System.out.println("Did not connected to camera.");
}
else
{
System.out.println("Conected to camera: "+capture.toString());
}
//create new Mat image
Mat frame = new Mat();
while(true){
capture.retrieve(frame);
Mat frame_gray = new Mat();
Imgproc.cvtColor(frame, frame_gray, Imgproc.COLOR_BGRA2GRAY);
Imgproc.equalizeHist(frame_gray, frame_gray);
MatOfRect faces = new MatOfRect();
face_cascade.detectMultiScale(frame_gray, faces);
Rect[] facesArray = faces.toArray();
for(int i=0; i<facesArray.length; i++)
{
Point center = new Point(facesArray[i].x + facesArray[i].width * 0.5, facesArray[i].y + facesArray[i].height * 0.5);
Core.ellipse(frame, center, new Size(facesArray[i].width * 0.5, facesArray[i].height * 0.5), 0, 0, 360, new Scalar(255, 0, 255), 4, 8, 0);
Mat faceROI = frame_gray.submat(facesArray[i]);
MatOfRect eyes = new MatOfRect();
//-- In each face, detect eyes
eyes_cascade.detectMultiScale(faceROI, eyes, 1.1, 2, 0,new Size(30,30), new Size());
Rect[] eyesArray = eyes.toArray();
for (int j = 0; j < eyesArray.length; j++)
{
Point center1 = new Point(facesArray[i].x + eyesArray[i].x + eyesArray[i].width * 0.5, facesArray[i].y + eyesArray[i].y + eyesArray[i].height * 0.5);
int radius = (int) Math.round((eyesArray[i].width + eyesArray[i].height) * 0.25);
Core.circle(frame, center1, radius, new Scalar(255, 0, 0), 4, 8, 0);
}
}
Highgui.imwrite(window_name, frame);
capture.release();
}
}
}

OpenCV is written in C/C++. Java wrappers allows access to native code via JNI. Unlike C++, Java doesn't support default parameter values. That documentation is for C++ and so has one function with 5 default parameter values. To cover for that, OpenCV Java wrapper has 6 methods. The error you are getting, ideally shouldn't be because of this.
Try below.
capture.release() is called in loop. Release should happen outside while loop. Use like
while( !done ) { ... }
After capture.retrieve(frame);, add if( frame.empty() ) { continue; }

Use of texture in extrude geometry (GWT)

I'm creating shapes with extrude geometry on GWT, now I want to apply textures on it but I am not able to apply it directly. How can I do that?
My code looks like :
ExtrudeGeometry extrudeMaterialBoard = null;
shapeExtrude.getExtrudeSettings().amount = (int) getMaterialThickness();
shapeExtrude.getExtrudeSettings().curveSegments = 1;
shapeExtrude.getExtrudeSettings().bevelThickness= 5;
shapeExtrude.getExtrudeSettings().bevelSize= 5;
shapeExtrude.getExtrudeSettings().bevelEnabled= true;
shapeExtrude.getExtrudeSettings().material = 0;
shapeExtrude.getExtrudeSettings().extrudeMaterial = 1;
extrudeMaterialBoard = new ExtrudeGeometry(DrawShape.getBottomBoard(), shapeExtrude.getExtrudeSettings());
camera = new PerspectiveCamera(
70, // fov
getRenderer().getAbsoluteAspectRation(), // aspect
1, // near
1000 // far
);
camera.getPosition().setZ(400);
String texture1 = "uvgrid0.jpg";
MeshBasicMaterial material = new MeshBasicMaterial();
material.setColor(getColor(COLOR_TRANSPARENT));
Texture texture = new Texture(texture1);
material.setMap(texture);
mesh = new Mesh(extrudeMaterialBoard, material);
getScene().add(mesh);
getRenderer().render(getScene(), camera);
If I use cube geometry then its running properly. But in case of extrude geometry its not working.
Thanks in advance.

Box2D crashes when destroying body (Expression: m_bodyCount < m_bodyCapacity)

Expression: m_bodyCount < m_bodyCapacity
That is the error I'm getting. The entire game crashes when I get this error. Now, here's the thing: I only get the error on certain I try to destroy, more specifically, bodies that were made during the game. What I mean is at the beginning of the game, I load the level and create all the bodies for each piece of the level. But, there are items that are made as the game runs, such as bullets, cannons, and coins. I can destroy any of the bodies created when the level is loaded, but when I try to destroy bodies created afterwards, I get the above error.
Here's an example. I spawn a CannonBall with my Cannon:
Cannon.class
if(reloadProgress >= RELOAD_TIME) {
CannonBall cannonBall = new CannonBall();
cannonBall.setXDirection(xDirection);
cannonBall.setYDirection(yDirection);
cannonBall.position.set(cannonBallPos);
Box2DHelper.makeFixture(cannonBall, BodyType.KinematicBody, origin, WorldController.b2world,
true, false);
Level.cannonBalls.add(cannonBall);
reloadProgress -= RELOAD_TIME;
} else {
reloadProgress += deltaTime;
}
Where Box2DHelper.makeFixture() is:
public static void makeFixture(GameObject object, BodyType type,
Vector2 origin, World b2world, boolean addUserData, boolean isMonster) {
BodyDef bodyDef = new BodyDef();
bodyDef.type = type;
bodyDef.position.set(object.position);
Body body = b2world.createBody(bodyDef);
if(addUserData)
body.setUserData(object);
object.body = body;
PolygonShape polygonShape = new PolygonShape();
origin.x = object.bounds.width / 2.0f;
origin.y = object.bounds.height / 2.0f;
polygonShape.setAsBox(object.bounds.width / 2.0f,
object.bounds.height / 2.0f, origin, 0);
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = polygonShape;
if(isMonster) fixtureDef.filter.groupIndex = Constants.GROUP_MONSTER;
body.createFixture(fixtureDef);
polygonShape.dispose();
}
So now I've created my CannonBall and set its body. Now, after 10 seconds, if it hasn't hit anything, I destroy it:
CannonBall.class
if (existanceDuration >= CANNON_BALL_EXISTANCE_DURATION) {
//Destroy cannon ball
CollisionHandler.bodiesToRemoveList.add(this.body);
}
Now that I have added the body into the list, I have to remove it:
CollisionHandler.class:
public static void removeSpecifiedBodies() {
Iterator<Body> i = bodiesToRemoveList.iterator();
while (i.hasNext()) {
Body desBod = i.next();
removeObjectFromList(desBod); //This is just to remove the object as well
WorldController.b2world.destroyBody(desBod);
if (perCharHitAction == true) {
performCharacterDeathAction(Level.character);
perCharHitAction = false;
}
i.remove();
}
bodiesToRemoveList.clear();
}
But now, I need to actually call this method. I do this in my main update method, right after b2world.step():
WorldController.class:
public void update(float deltaTime) {
...
b2world.step(deltaTime, 8, 3);
if (CollisionHandler.bodiesToRemoveList.size() > 0)
CollisionHandler.removeSpecifiedBodies();
Now, like I stated before, this method works fine when I destroy objects made at the loading of the level, but on objects I later create, it doesn't.
Why does my game keep crashing after trying to destroy box2d bodies later created in my game?
Edit: I call this method right after the level has loaded for creating the object's bodies:
private void initPhysics() {
if (b2world != null)
b2world.dispose();
b2world = new World(new Vector2(0, -9.81f), true);
Vector2 origin = new Vector2();
b2world.setContactListener(new CollisionHandler());
// Create Box2D Fixtures
for (Grass grass : Level.grasses)
Box2DHelper.makeEdgeChain(grass, BodyType.StaticBody, origin,
b2world, true);
// Bricks
for (Brick brick : Level.bricks)
// Box2DHelper.makeFixture(brick, BodyType.KinematicBody, origin,
// b2world, true);
Box2DHelper.makeEdgeChain(brick, BodyType.StaticBody, origin,
b2world, true);
// Item Boxes
for (ItemBox box : Level.itemBoxes)
Box2DHelper.makeFixture(box, BodyType.KinematicBody, origin,
b2world, true, false);
//Enemies
for (Goomba goomba : Level.goombas)
Box2DHelper.makeFixture(goomba, BodyType.DynamicBody, origin,
b2world, true, true);
for (Koopa koopa : Level.koopas)
Box2DHelper.makeFixture(koopa, BodyType.DynamicBody, origin,
b2world, true, true);
// Cannons
for (Cannon cannon : Level.cannons)
Box2DHelper.makeFixture(cannon, BodyType.KinematicBody, origin,
b2world, true, true);
// Character
BodyDef bodyDef = new BodyDef();
bodyDef.type = BodyType.DynamicBody;
bodyDef.position.set(Level.character.position);
Body body = b2world.createBody(bodyDef);
body.setUserData(Level.character);
Level.character.body = body;
CircleShape polygonShapeHead = new CircleShape();
origin.x = Level.character.circleBoundOrigin.x * 2.0f;
origin.y = Level.character.circleBoundOrigin.y * 3.0f;
// polygonShapeHead.setAsBox(level.character.circleBoundOrigin.x,
// level.character.circleBoundOrigin.y, origin, 0);
polygonShapeHead.setPosition(origin);
polygonShapeHead.setRadius(Level.character.circleBoundOrigin.x);
FixtureDef fixtureDefHead = new FixtureDef();
fixtureDefHead.shape = polygonShapeHead;
fixtureDefHead.friction = Level.character.friction.x;
body.createFixture(fixtureDefHead);
polygonShapeHead.dispose();
PolygonShape polygonShapeBod = new PolygonShape();
origin = Level.character.rectBoundOrigin;
polygonShapeBod.setAsBox(Level.character.rectBoundOrigin.x,
Level.character.rectBoundOrigin.y, origin, 0);
FixtureDef fixtureDefBod = new FixtureDef();
fixtureDefBod.shape = polygonShapeBod;
fixtureDefBod.friction = Level.character.friction.x;
body.createFixture(fixtureDefBod);
polygonShapeBod.dispose();
}
Maybe the issue when creating bodies later in the game is the b2world?

I had the same Error - I figured out, that it happens if you destroy the same body multiple times.
In my case I put the body into a list in the contact listener.. but I didn't make sure it was in the list only once.
That also explains why your problem was fixed once you worked with a boolean flag, that also made sure the same body was only destroyed once.
In short: You get this error if you try to destroy the same body over and over again.

How to display frame only when required & set frame to appear on top all the time?

My program will alert users when data (stock name & price) in the database matches with the data (stock name and price) from Yahoo Finance. With the help of HarryJoy i'm able to implement a pop up notification.
Problem is the pop up location on the screen is based on the database loop (int db). The frame will pop even if data doesn't match.
How can I set a counter or some method to pop up the frame only when database data = Yahoo Finance data? Also, my notification panels appears to be behind the main frame. How can make the panels appear on top of my main frame?
I hope I've given enough information, please ask if still unclear. Any guidance will be appreciated! Thanks!
In the database (using code sample only to display my explanation in order, source code below).
Object 1 = match
Object 2 = doesn't match (hence there's a gap)
Object 3 = match
Object 4 = match
Screenshot:
Code:
for (int db=0; db<= rowCount; db++)
{
Object popSymbol = table.getModel().getValueAt(db, 0);
String popupSymbol = popSymbol.toString();
Object popValue = table.getModel().getValueAt(db, 1);
String str = popValue.toString();
double popStockValue = Double.valueOf(str).doubleValue();
String stockNameDB = popupSymbol;
StockPara stock = YahooStock.getInstance().getStockPrice(stockNameDB);
double stockPriceDB = Math.round(stock.getPrice());
final JFrame popUpFrame;
final JPanel popupPanel;
if (stockPriceDB == popStockValue)
{
String header = "Stock: " + stock.getTicker() + " is now # " + stock.getPrice();
String message = "";
popUpFrame = new JFrame();
popUpFrame.setSize(320,90);
popUpFrame.setUndecorated(true);
popUpFrame.getContentPane().setLayout(null);
popupPanel = new JPanel();
popupPanel.setBorder(new LineBorder(new Color(0, 0, 0)));
popupPanel.setBounds(0, 0, 320, 90);
getContentPane().add(popupPanel);
popupPanel.setBackground(new Color(255, 255, 224));
popupPanel.setLayout(null);
popUpFrame.add(popupPanel);
// Other labels, images, etc.
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Insets toolHeight = Toolkit.getDefaultToolkit().getScreenInsets(popUpFrame.getGraphicsConfiguration());
popUpFrame.setLocation(screenSize.width - popUpFrame.getWidth(), screenSize.height - toolHeight.bottom - (popUpFrame.getHeight() * (db+1)));
}
}

To solve your issue quickly, simply create an additional counter (int counter = 0;). Then use that counter instead of db to position your popUpFrame and right after that increment counter.
int counter = 0; // Initiate outside de loop
...
for(int db=0; db<= rowCount; db++) {
...
if (stockPriceDB == popStockValue) {
...
popUpFrame.setLocation(screenSize.width - popUpFrame.getWidth(),
screenSize.height - toolHeight.bottom - (popUpFrame.getHeight() * (counter+1)));
counter++;
}
}
To bring your frame to the front use:
popUpFrame.toFront()
and to force it to be always on top (although I would really not recommend that because it is more annoying for the user than anything else):
popUpFrame.setAlwaysOnTop(true);
This is not necessarily supported by all platforms.

for on top issue, use
notificationPanel.requestFocus();