3 bugs. Find them.

find-three-bugs.java

import java.util.*;
import java.util.stream.Collectors;

public class FindMyBugs {
	Byte[] buffer;

	public FindMyBugs(byte[] buffer) {
		this.buffer = buffer;
	}

	// calculate (simplified) checksum for all elements in buffer.
	public int stupidChecksum() {
		int sum = 0;
		for(int i = 0; i <= buffer.length; sum += buffer[i], i++)
		return sum;
	}

	// return all uneven elements in buffer
	public List<Byte> getUneven() {
		return Arrays.asList(buffer).stream().filter(b -> b % 3 == 0).collect(Collectors.toList());
	}
}

... and one bonus bug :)