Retrofitting null-safety onto Java at Meta
It's so sad that Java 8 had the chance to really fix the null problem, but gave us only the half-assed `java.util.Optional<T>`. Rather than implementing optional values at the language level, it's just another class tossed into the JRE.<p>This is perfectly legal code, where the optional wrapper <i>itself</i> is null:<p><pre><code>    Optional<String> getMiddleName() {
        return null;
    }</code></pre>