Iscar Ltd. CFO Danny Goldman and CEO Jacob Harpaz are candidates to succeed Berkshire Hathaway Inc. chairman and CEO Warren Buffett, according to Wall Street Journal columnist Jason Zweig.Zweig based his assessment on Buffett’s annual letters to shareholders. Zweig ranked Goldman and Harpaz No. 14 and No. 15 as possible Buffett successors. They are far below the rankings of Ajit Jain, head of Berkshire’s reinsurance group, whom Buffett sited 102 times in his annual letters, and Geico CEO Tony Nicely, who was cited 60 times. Buffett has written more than 400,000 words in his annual letters since 1977. Buffett, 81, last week announced that he had stage 1 prostate cancer, the least malignant form of the disease, and that he would undergo chemotherapy.He was optimistic and said he would continue running Berkshire Hathaway.Nonetheless, the announcement raised concern about the day after Buffett and who his successor would be.He has already said that Berkshire Hathaway’s board of directors has picked a successor, with two alternatives if necessary, but he has declined to mention any names.