Questionable use of Double Checj

Questionable.java

class QuestionableUseOfDoubleCheck {
    private long firstAccess = -1;

    public long accessSomething() {
        if (firstAccess != -1) {
            return this.firstAccess;
        }
        synchronized (this) {
            if (this.firstAccess != -1) {
                return this.firstAccess;
            }
            this.firstAccess = System.currentTimeMillis();
            return this.firstAccess;
        }
    }
}