Oracle Corp. (ORCL) said Thursday that antirust regulators at the U.S. Department of Justice have cleared its $7.4 billion deal to buy Sun Microsystems Inc. (JAVA), removing a major hurdle for the transaction.

Oracle, which makes databases and other software for large corporations, has said it hopes to close the deal this summer.

The Redwood City, Calif.-based company has said its acquisition of Sun, which makes computer servers and owns the widely-used Java technology platform, would transform the information-technology industry.

Oracle hasn't previously had a significant presence in the hardware business, and it called Sun's Java the most important software it has ever acquired.

The deal, which came as something of a surprise when it was announced in April, materialized after acquisition talks between International Business Machines Corp. (IBM) and Santa Clara, Calif.-based Sun failed.

The Justice Department's clearance comes after it extended its antitrust review of the deal back in June. An antitrust lawyer for Oracle said the department needed additional time to review one issue about the way rights to Java are licensed.

Sun's shareholders approved the deal last month.

European antitrust regulators are also looking at the deal. The European Commission must decide by Sept. 3 whether to clear the acquisition or launch a detailed investigation.

-By Brent Kendall, Dow Jones Newswires; 202-862-9222; brent.kendall@dowjones.com