OPINION

Louis Watley seeks a writ of mandamus, pursuant to 28 U.S.C. § 1651, directing the United States District Court for the District of New Jersey to rule on his habeas corpus petition. Subsequent to the filing of this mandamus petition, however, the District Court dismissed Watley’s habeas petition without prejudice for failure to exhaust state remedies. 1 Accordingly, to the extent Watley seeks to have this Court order the District Court to rule on the habeas petition, his mandamus petition will be denied as moot. See Blandak v. Allegheny Ludlum Corp., 77 F.3d 690, 698-99 (3d Cir. 1996) (“If developments occur during the course of adjudication that ... prevent a court from being able to grant the requested relief, the case must be dismissed as moot.”). And to the extent Wat-ley requests that we “declare” as “arbitrary, capricious, and [an] abuse of power” the District Court’s seven-month delay in adjudicating the habeas petition, that request is denied; mandamus is not a substitute for an appeal. See In re Chambers Dev. Co., 148 F.3d 214, 226 (3d Cir. 1998).