Opponents of $7.4 billion merger of Oracle Corp. (ORCL) and Sun Microsystems Inc. (JAVA) will air their views at a European Commission hearing on whether to allow the merger, two people familiar with the hearing. According to WSJ report, Microsoft officials will be offering arguments as to why the merger shouldn’t be allowed. U.S. antitrust regulators already have OK’d the Sun/Oracle merger. But the EC has not, seemingly because of fears that Oracle might kill off Sun’s open-source MySQL database. Oracle submitted its written defense of the take over to the EC on December 4, according to Wall Street Journal. Now the Commision must either clear or block the deal by January 27 (though that deadline may be pushed back yet again, the Journal notes).