Byte [] and java.lang.outofmemoryerror read / write file bitwise

I'm committed to erasing some free space in Android. Here's my code:

private void creatingFileDelete(int size, int passMode) 
    {
        File lastFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath(),"/.tmpToDelete/last.txt");
        if (lastFile.exists() == false) 
        {
        try 
        {
            lastFile.createNewFile();
        }//End of try block
        catch (IOException e) 
        {
            e.printStackTrace();
        }//End of catch block
    }//End of if condition

    try 
    {
        RandomAccessFile rwFile = new RandomAccessFile(lastFile, "rw");
        rwFile.setLength(1024*1024*size);
        FileChannel rwChannel = rwFile.getChannel();
        int numBytes = (int) rwChannel.size();
        MappedByteBuffer buffer = rwChannel.map(FileChannel.MapMode.READ_WRITE, 0, numBytes);
        buffer.clear();
        byte[] randomBytes = new byte[numBytes];

        new Random().nextBytes(randomBytes);
        Arrays.fill(randomBytes, 0, randomBytes.length, (byte) passMode);
        buffer.put(randomBytes);

        buffer.force();
        rwFile.close();
    }//End of try block
    catch (Exception e) 
    {
        Log.e("Clean free space---","message :" +e.getMessage());
    }//End of catch block
}//End of creatingFileDelete 

During wiping, the following crashes occur

java.lang.RuntimeException: An error occured while executing doInBackground()
          at android.os.AsyncTask$3.done(AsyncTask.java:299)
          at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
          at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
          at java.util.concurrent.FutureTask.run(FutureTask.java:239)
          at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
          at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
          at java.lang.Thread.run(Thread.java:856)
    Caused by: java.lang.OutOfMemoryError
          at xxx.creatingFileDelete(CleanFreespace.java:2634)
          at xxx.CleanFreespace.access$71(CleanFreespace.java:2610)
          at xxx.CleanFreespace$15.doInBackground(CleanFreespace.java:2100)
          at xxx.CleanFreespace$15.doInBackground(CleanFreespace.java:1)
          at android.os.AsyncTask$2.call(AsyncTask.java:287)
          at java.util.concurrent.FutureTask.run(FutureTask.java:234)
          ... 4 more

Friend, how can I solve this problem

resolvent:

OutOfMemoryError 

When you receive an error such as OUTOFMEMORY, it means that your application is out of memory because your application takes up more space and is allocated to it by the system

Put this attribute Android: largeheap = "true" in the < application / > start manifest.xml file

for example

 <application
    android:name="support.classes.StartUp"
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:largeHeap="true" // you are increasing the heap space for the app 
    android:theme="@style/AppThemeTest">

If you just want to free up some space, you'd better let the Android system handle it, which is the best

System.gc()

Please call the garbage collector before performing any memory consuming tasks, because it will free up some space for you. If you try to call this command after the task is completed, it will be useless