@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        SessionId sessionId = (SessionId) o;

        return id.equals(sessionId.id);
    }
An id which is unique across the cluster of nodes

@author baldersheim
container-search/src/main/java/com/yahoo/search/query/SessionId.java