Java Applets Cause IE 3.02 to Stop Responding w/ SP3

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0
• Microsoft Internet Explorer version 3.02

SYMPTOMS

Internet Explorer version 3.02 may hang when connecting to a Web link that contains a Java application after you have installed Windows NT version 4.0 Service Pack 3. The application will stop responding only if the Display Properties Color Palette is set to True Color.

CAUSE

In Windows NT version 4.0 Service Pack 3 the GetDIBits API does not fill the bit fields when a BI_RGB (uncompressed) DIB is returned on a True Color (32 bpp) display. This GDI change was made because the bit fields are not required in this case. As a side effect, this change may cause a regression in applications that expect a valid RGB mask on a True Color display.

The Java virtual machine included with Internet Explorer 3.02 calls GetDIBits when initializing the display palette. The Java virtual machine expects a valid, signed RGB mask value larger than 0x80h and, if a value less than 0x80h is received, it doubles the mask value in a tight loop until it is larger than 0x80h. Because Service Pack 3 GetDIBits do not fill the bit fields when a BI_RGB is returned, applications that evaluate the RGB mask receive an unlikely result that can be negative (for example, 0xffffffe0h.) When the Java virtual machine evaluates the RGB mask and receives a negative value, it loops forever and causes Internet Explorer to stop responding.

It is important to note that the Java virtual machine should be treating the RGB Mask as an unsigned integer. There are some conditions where an ATI video card returns a valid RGB Mask value of 0xff000000h causing the Java virtual machine to loop forever because it is not treating the mask as an unsigned integer. A separate fix for the Java virtual machine issue with ATI video cards in True Color will be available in Internet Explorer 4.0. The Java code is licensed from Sun Microsystems, Inc.

RESOLUTION

To work around this problem, do not use the True Color palette in Display Properties. To resolve this problem, obtain the hotfix mentioned below or wait for the next service pack.

Win32k.sys was modified to return a valid RGB color mask on True Color display systems.

Java-fix has been superseded by Getadmin-fix. You can find the latest hotfix at the following Microsoft ftp site:

   ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/
   hotfixes-postSP3/getadmin-fix

   ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/
   hotfixes-postSP3/archive/java-fix

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.