Although Microsoft (MSFT) emphasized that the problems are rare, the latest bugs cap several weeks of reports of software glitches in Internet Explorer 3.0, as well as Netscape Communications' competing Navigator 3.0 browser. The problems also highlight the increasing difficulty encountered by companies in removing bugs from their browsers as the pace of Net development accelerates.
Today, Microsoft confirmed the existence of two unrelated bugs in Internet Explorer 3.0's Java engine and said it is working to repair the problems.
One bug affects the the just-in-time compiler in the browser and Microsoft's Visual J++ Java development tool. It could require that the JIT compiler, which speeds up the performance of applets, be disabled to allow Java programs to run, said Mike Smith, a product manager at Microsoft.
A second bug involves Internet Explorer's Java "zip" class libraries and could break applets altogether, though it only affects users of the beta version of Visual J++ who have upgraded to the final version of Internet Explorer 3.0, Smith said.
By press time, Microsoft hadn't had an opportunity to evaluate yet another potential Java bug. On at least one Web site, the bug prevents an applet from running on Internet Explorer 3.0, though the program works on Navigator 3.0.
Most of the bugs were first made public by users on Usenet discussion groups dedicated to Web browsers and Java.
Earlier last month, Microsoft raced to patch several Internet Explorer 3.0 bugs not related to Java, including a security hole and a glitch that caused the browser to forget a user's name and password. Microsoft has posted a single patch for both problems on its Web site, but it has not devised a plan yet for fixing the latest Java bugs.
In the meantime, Microsoft officials said most of the Internet Explorer problems are isolated incidents and not part of an epidemic.
"It's very easy to lose perspective on Usenet," Smith said. "The number of people who are complaining are a very vocal but small group."
In mid-August, a beta version of Netscape Navigator 3.0 was also beset by a Java bug, which the company said it fixed in the final version of the browser.