Sun Hotspot JVM or IBM J9 JVM

In earlier (pre- AX-3.6) releases, all QNX-based JACE controllers used the IBM J9 JVM (Java Virtual Machine) to host the Niagara Runtime Environment (NRE) for running a station. Starting in AX-3.6, more recent controllers, along with the newest (JACE-3E, JACE-6E, JACE-603, JACE-645), now use Oracle's Sun Hotspot Java VM--the same VM type used in Windows-based NiagaraAX platforms.

For any JACE-6 or JACE-7 series controller upgraded from an earlier (pre- AX-3.6) release, the core software distribution automatically replaces the J9 JVM with the Hotspot JVM. The associated license upgrade includes the required "sunj2se" feature, needed to allow the JACE to operate.

The Hotspot JVM provides a significant performance improvement. Plus, the Hotspot JVM provides J2SE support--useful for developers and system integrators skilled in creating program components or custom applications (written in Java). This allows many of the newer Java APIs, which have never been supported by the J2ME version in the IBM J9 JVM.

NOTE: Due to resource limits, the JACE-2 series (all NPM2-based) controllers and previous (JACE-4, JACE-5) continue to use the IBM J9 JVM, regardless of NiagaraAX release level. For the same reason in AX-3.7, these controllers also continue to use a Niagara platform daemon (niagarad) written in "native code", rather than a Java-based platform daemon (see “Platform daemon (niagarad”) for related details).

For the most part, these differences in Java VM and platform daemon are typically "transparent" to the normal configuration of the controller’s hosted station or platform.

However, there are now notable advantages for a controller using the Hotspot JVM, as follows:

Supports IPv6 in its TCP/IP platform configuration. See “TCP/IP changes in AX-3.6” for related details.
When running AX-3.7 or later, capable of supporting secure encrypted (SSL) connections. See platform connection.

For reasons like these, the two subgroups of QNX-based controllers are sometimes referred to as either "Hotspot JACE" or "J9 JACE" in this document.

Sun Hotspot JVM or IBM J9 JVM

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