When you need to interact with files, there's the possibility to read all bytes from the file with Files.readAllBytes. But be aware of the kinds of files your application will deal with because the Java API files have a limit for the buffer that is defined as Integer.MAX_VALUE as you can see above or at the OpenJDK sources.

public static byte[] readAllBytes(Path path) throws IOException {
    try (FileChannel fc = FileChannel.open(path)) {
        long size = fc.size();
        if (size > (long)Integer.MAX_VALUE)
            throw new OutOfMemoryError("Required array size too large");

        byte[] arr = new byte[(int)size];
        ByteBuffer bb = ByteBuffer.wrap(arr);
        while (bb.hasRemaining()) {
            if (fc.read(bb) < 0) {
                // truncated

        int nread = bb.position();
        return (nread == size) ? arr : Arrays.copyOf(arr, nread);

With that in mind, check if isn't better read chunks of bytes e work with that slice in exchange of loading the whole file into the memory ;). Above a simple example of how you can read chunks of bytes from the file.

byte[] buffer = new byte[1024];
FileInputStream in = new FileInputStream(file);
int rc = in.read(buffer);
while (rc != -1)
    //crazy stuff here with buffer
    rc = in.read(buffer);