Sequels usually are sure box office bets for summer. Johnny Depp (l.), Penelope Cruz (r.), and Ian McShane appear in a scene from 'Pirates of the Caribbean: On Stranger Tides,' about a quest for the fountain of youth. 'Tides' is the fourth film in the 'Pirates' franchise, based on a Walt Disney theme park ride. Peter Mountain/Disney/AP/File
Po (c.), voiced by Jack Black, Tigress (r.), voiced by Angelina Jolie, and Monkey (l.), voiced by Jackie Chan, are shown in a scene from 'Kung Fu Panda 2.' The original computer-animated feature was well-received in China for being faithful to Chinese culture. DreamWorks/Paramount Pictures/AP/File
Vin Diesel (l.) and Paul Walker star in 'Fast Five.' The film is a departure from the four previous 'Fast and Furious' films, which focused on street racing and car culture, and features a heist action plot to attract more viewers. Jaimie Trueblood/Universal Pictures/AP/File
Lightning McQueen (l.), a race car voiced by Owen Wilson, Mater (c.), a tow truck voiced by Larry the Cable Guy (Daniel Lawrence Whitney), and Finn McMissile (r.), voiced by Michael Caine, are shown in a scene from 'Cars 2,' an international car race caper. The original 'Cars' was released in 2006. Disney/Pixar/AP/File
January Jones (l.) and Kevin Bacon appear in a scene from 'X-Men: First Class,' the fifth installment in the franchise, which is set in the 1960s and explores the relationship between Professor X and Magneto, along with the origins of their groups, the X-Men and the Brotherhood of Mutants. 20th Century Fox/Newscom/File
From left, actors Jeremy Renner, Tom Cruise, and Paula Patton, and director Brad Bird promote 'Mission: Impossible - Ghost Protocol' in Dubai on Oct. 29, 2010. The crew was in Dubai to film an action scene for the fourth film in the franchise featuring the Burj Khalifa, the world's tallest building. AFP/Getty Images/Newscom/File
Josh Duhamel (c.) stars again in 'Transformers: Dark of the Moon,' the third installment of the Transformers movies. The lucrative action blockbuster franchise, directed by Michael Bay, is based on Hasbro's Transformers toy line of alien robots. Paramount Pictures/Newscom/File
Daniel Radcliffe (l.) stars as Harry Potter and Ralph Fiennes plays his nemesis, Voldemort, in the widely-anticipated showdown of 'Harry Potter and the Deathly Hallows: Part 2.' The film is the eighth and final movie in the series based on J.K. Rowling's books. Warner Bros. Pictures/AP/File
From left, Bradley Cooper, Zach Galifianakis, and Ed Helms reprise their characters from 'The Hangover' in 'The Hangover Part II,' this time taking their bizarre exploits to Bangkok. Melinda Sue Gordon/Warner Bros. Pictures/AP
Obama said the US would defend Japan in any conflict with China over the Senkaku islands. His trip has targeted better relations with Prime Minister Abe, whose comments about Japan's World War II history have caused strains.
President Obama has assured Japan that the United States will defend its ally in the event of a conflict with China over the Senkaku islands, but he warned Beijing and Tokyo that the territorial dispute must be settled through dialogue.