OutOfMemoryException when reading bytes from file

Question

I'm trying to make a hex dumping application and for that, I need to read the file bytes. I'm using apache io version 2.8.0 to do the hex dumping. This is the code I'm using:

     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            try {
                byte[] bytes = Files.readAllBytes(Paths.get(getPackageManager().getApplicationInfo("com.pixel.gun3d", 0).nativeLibraryDir.concat("/libil2cpp.so")));
                Log.e("MainActivity", dumpHex(bytes));
            } catch (PackageManager.NameNotFoundException | IOException e) {
                e.printStackTrace();
            }
        }

    private String dumpHex(byte[] bytes) {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try {
            HexDump.dump(bytes, 0, out, 0);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new String(out.toByteArray());
    }

And the error I get is this: java.lang.OutOfMemoryError: Failed to allocate a 155189264 byte allocation with 25165824 free bytes and 94MB until OOM, max allowed footprint 328602112, growth limit 402653184 I looked it up and none of the suggestions I tried such as adding android:largeHeap="true" and android:hardwareAccelerated="false" to the manifest worked. Any help is appreciated <3

Either limit yourself to small files or find some other way that does not require you to read in the entire file at once (let alone try to maintain three copies of the file, as your current code does). — CommonsWare
– CommonsWare, Commented Jan 29, 2022 at 15:21
Thank you! Perhaps, could give provide me a way to read a file into smaller chunks? — Arc Mods
– Arc Mods, Commented Jan 29, 2022 at 15:25

Orr Benyamini · Accepted Answer · 2022-01-29 17:16:33Z

2

When reading file it is recommended to partition the read into small chunks to avoid this kind of errors. Reading the whole files bytes into byte array has limitations, for example the file size is over Integer.MAX_VALUE you will get an OutOfMemoryException.

Try doing something similar to this:


byte[] buffer = new byte[1024];
FileInputStream fis = new FileInputStream(file);
int readBytesNum = fis.read(buffer);
while (readBytesNum > 0)
{
    //do what you need
    readBytesNum = in.read(buffer);
}

This means you would need to change the implementation of HexDump to handle files in partitions

answered Jan 29, 2022 at 17:16

Orr Benyamini

4053 silver badges10 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

OutOfMemoryException when reading bytes from file

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related