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

        MultiClassKey that = (MultiClassKey) o;

        if (!first.equals(that.first)) {
            return false;
        }
        if (!second.equals(that.second)) {
            return false;
        }

        return true;
    }
A key of two {@link Class}es to be used in hashed collections.
core/src/main/java/com/bumptech/glide/util/MultiClassKey.java