Sun has recently released the following information:

This notice addresses the new Intel Pentium 4 processor and several Sun binary JDK/JREs and J2SE products that use a 3rd-party Just-in-Time (JIT) compiler. Sun products affected are for the Windows operating system only.

The following binary releases from Sun do not currently support the Intel Pentium 4 processor:

JDK/JRE v 1.1.6
JDK/JRE v 1.1.7B
JDK/JRE v 1.1.8

J2SE v 1.2.0
J2SE v 1.2.1
J2SE v 1.2.2

Note that the currently available J2SE v 1.3.0 (and higher) does support the Intel Pentium 4 processor (this is due to the use of the Java HotSpot Virtual Machine).

Sun will make available updated binary releases that include support for the Intel Pentium 4 processor. Binary customers will need to upgrade to the following:

JDK 1.1.8_006 -> target availability date 12/22/2000
J2SE v 1.2.2_007 -> target availability date 12/22/2000

FAQ:

Q: Will Sun provide binary patches for JDK/JRE 1.1.6, 1.1.7B and J2SE v1.2.0/1?
A: Sun recommends customers upgrade to either JDK/JRE 1.1.8_006 or to a supported J2SE release (v 1.2.2_007 or v 1.3.0_xx).

You can check for the JDK updates here:

JDK 1.2.x: http://java.sun.com/products/jdk/1.2/
JDK 1.1.x: http://java.sun.com/products/jdk/1.1/

This means that JBuilder 3.5 will not install on a Pentium 4 as the installation programs run on JRE 1.2.2.

The JBuilder 4 install launcher will also not work on a Pentium 4 as it also uses JRE 1.2.2. However, the individual component installers will work since they use JRE 1.3. Please see the installation instructions on the JBuilder 4 CD for more details on how to install JBuilder without the launcher.

As a further workaround, you should be able to install JBuilder 3.5/4 on a non-Pentium 4 Windows machine and copy the entire directory structure to your Pentium 4 machine. Note that for JBuilder 3.5 you will also need to install the updated version of JDK 1.2.2 and point JBuilder at this JDK. Read this to learn how to change JBuilder's JDK.