WASHINGTON (AP) _ China is putting heavy emphasis on modernizing its naval forces but realizes it will take many years to fully absorb new technologies, says the U.S. Navy's senior officer, who recently met with his counterpart in China.

``They were very realistic,'' said Adm. Jay Johnson, the chief of naval operations, in assessing that it would take ``years, even decades'' to modernize the Chinese navy.

Johnson was in China earlier this month. As part of his visit he spent a day at sea aboard a Chinese destroyer participating in an anti-submarine warfare exercise.

Johnson, speaking Thursday to a symposium on the future of U.S. security strategy in East Asia, described Chinese naval officers as ``seemingly forthright'' in sharing with him the Chinese navy's roles, missions and goals for the future. He did not elaborate on the roles and goals.

``One message that was delivered to me time and time again in China was, the No. 1 priority in China is economic growth, and the military clearly stacks underneath that,'' Johnson said.

He said he invited his Chinese navy counterpart to visit the United States next year, and they discussed the possibility of student exchanges between the U.S. and Chinese naval war colleges.