A party, having “standing” may file an action seeking a judicial declaration that a patent, or patents, are invalid, unenforceable, and⁄or not infringed by anything the party is doing.
In essence, a declaratory judgment action (“DJ action”) is a jurisprudential implementation of the old adage,“Do unto others as they would do unto you—only do it first!” It is an opportunity to strike first, rather than waiting for a patentee to file a suit alleging patent infringement.
“Standing,” which is a prerequisite to the bringing of a declaratory judgment action, is, essentially, a requirement that the plaintiff (the pestilential infringer) have an objectively reasonable apprehension of imminent suit by the (righteous, oppressed) patentee.
“I’m not infringing; I, myself, have a patent on this product.” Even if true, this will avail naught. A patent is a negative right--It does not convey the affirmative right to make the patented product.