SHA-256FileDigest.java

import com.google.common.hash.Hashing;
import com.google.common.hash.HashingInputStream;

import java.io.FileInputStream;

public class App {
    public static void main(String[] args) throws Exception {
        // read a file, create a hashing stream for SHA-256
        try (HashingInputStream hashingInputStream = new HashingInputStream(Hashing.sha256(), new FileInputStream("/Users/matttodd/dev/personal/file-digest/hello2.txt"))) {
            // read the stream fully to calculate hash
            while (hashingInputStream.read() != -1);

            System.out.println(hashingInputStream.hash());
        }
    }
}