The javadoc for Attributes.equals says the following:

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/**
     * Compares the specified Attributes object with this Map for equality.
     * Returns true if the given object is also an instance of Attributes
     * and the two Attributes objects represent the same mappings.
     *
     * @param o the Object to be compared
     * @return true if the specified Object is equal to this Map
     */
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The implementation does not validate the the object passed to equals is an instance of Attributes so it could just be a Map.