Japan's corporations have become more optimistic in the past three months, logging an improvement in business confidence for the second time in a row, the Bank of Japan's latest "tankan" business sentiment survey shows.

The BOJ's quarterly survey for June, released Monday, solidifies the government's view that the economy has stopped worsening.

The diffusion index -- the percentage of firms that feel business is favorable minus those that feel business is unfavorable -- for large manufacturers jumped to minus 37, up 10 points from the March survey, marking the biggest recovery since August 1994.