ArrayIndexOutOfBoundsException xmlserializer

Question

I have a code that creates a kml file using XMLserializer. It works fine creating the different polygons, but I'm having an error with closing the xml that I really don't understand.

02-09 10:03:02.919 24712-26301/com.example.accgps W/System.err: java.lang.ArrayIndexOutOfBoundsException: length=24; index=-3
02-09 10:03:02.919 24712-26301/com.example.accgps W/System.err:     at org.kxml2.io.KXmlSerializer.endTag(KXmlSerializer.java:493)
02-09 10:03:02.919 24712-26301/com.example.accgps W/System.err:     at com.example.accgps.KMLHelper.SerialEnd(KMLHelper.java:150)
02-09 10:03:02.919 24712-26301/com.example.accgps W/System.err:     at com.example.accgps.RefreshKML$1.run(RefreshKML.java:283)
02-09 10:03:02.919 24712-26301/com.example.accgps W/System.err:     at java.lang.Thread.run(Thread.java:818)*

The call to the SerialEnd() is done after creating the polygons, which work fine, so I don't know why it is out of bounds:

        for (s = 0; s < PolyArray.size(); s++) {
            polygon = PolyArray.get(s);
            kH.SerialPlacePol("Tramo " + i, polygon);
            i++;
        }
        Log.i(TAG, "RefreshKML: se han creado " + (i - 1) + " tramos");
        editor.putInt("poligonos", i);
        editor.apply();
    } else {
        Toast.makeText(getApplicationContext(),"No existen datos suficientes para "+
        "generar el archivo KML",Toast.LENGTH_SHORT).show();
    }
} else {
    Log.d(TAG, "RefreshKML: No hay datos de GPS suficientes");
}

if (end) { //Solo cierra el archivo si se termina la recopilación de datos
    kH.SerialEnd();
    end = false; //En caso de que no se completó esta opción
    copyAllFiles();
}

The error is provoked in the first line of the SerialEnd() method:

public void SerialEnd () {
    try{
        serializer.endTag(null,"Document"); //THIS IS THE LINE WITH THE ERROR
        serializer.endTag(null,"kml");
        //serializer.endDocument();
        //serializer.flush();
        fileos.close();
        Log.d(TAG,"KMLHelper: SerialEnd cierra archivo KML");
    }catch(Exception e){
        Log.d(TAG,"KMLHelper: Exception occured in SerialEnd");
        e.printStackTrace();
    }
}

I have tried to find an answer in other questions, but I didn't find the proper solution, maybe the serializer is closed, but I haven't done that yet

This is how I create the XMLserializer, in case you see a problem in here:

public KMLHelper(File file) {
    try{
        serializer.endTag(null, "Document");
        serializer.endTag(null, "kml");
        serializer.endDocument();
        serializer.flush();
        Log.d(TAG,"KMLHelper: SerialEnd cierra archivo KML");
    }catch(Exception e){
        Log.d(TAG,"KMLHelper: Exception occurred in SerialEnd");
        e.printStackTrace();
    }finally {
        try {fileos.close();} catch (IOException io) {io.printStackTrace();}
    }
}

Edit: I have made some changes in the SerialEnd(), put the closure of the file in the finally and uncommented the endDocument method. I've also controlled the access to the thread that creates the xml file with a synchronized to the creation of the intent that is controlling the creation of the XML file with all the polygons.

Answer 1

Solved! The problem was that it was creating 2 XMLserializer working on the same file. I changed how the service calls the method, now I'm using a background Thread to make the calls and I control the execution with a join(), so there is only 1 execution at a time.