JAKARTA – Indonesian navy divers were searching through plane debris and seabed mud Tuesday looking for the black boxes of a Sriwijaya Air jet that nosedived into the Java Sea over the weekend with 62 people aboard.A navy ship earlier picked up intense pings being emitted from the boxes containing the cockpit voice and flight data recorders of the Boeing 737-500 that went down Saturday minutes after taking off from the capital, Jakarta, in heavy rain.The divers were using high-tech “ping locator” equipment to further narrow their hunt beneath 20 meters (65 feet) of seabed mud but the black boxes are buried under tons of sharp objects in the wreckage, Navy Chief Adm.