The Open Group claims a Turbo-J compiler it will begin selling within 60 days for use Hewlett-Packard Co’s PA-RISC computers overcomes some of the limitations of Java JIT just-in-time compiler technology by enabling users to store Java applications as highly-optimized native executables or dynamically loadable shared libraries that do not need to be recompiled each time they are used. JITs provide on-the-fly translation of Java code as an application is downloaded from the network. Turbo-J compiles machine-independent Java byte-code (zeros and ones rather than human-readable source code) into machine code which can run faster than interpreted byte-code because it is optimized for the system’s specific or native instruction set. Unlike JITs which compile whole applications on the fly, Turbo-J optimizes only performance-critical parts of an application and provides a persistent storage feature. Also, because Turbo-J requires the system to perform complex optimization tasks on the entire program the compiler works off-line, generating code in a few minutes rather than in a few seconds like JITs. However because the resulting code can be archived for re-use – unlike JITs or other on-the-fly code-optimizers – Open Group says applications pre-compiled using Turbo-J run up to four times faster than JIT code and up to 100 times faster than standard byte code runs. HP provided most of the funding for development of Turbo-J which is why it’s up on HP-UX, although versions of Linux-on-Intel and for Wind River Systems Inc VxWorks embedded operating system are due next quarter. (Open Group is currently developing two versions of an embedded J-Lite Java execution environment for Pentium and PowerPC; one incorporates the VxWorks microkernel, the other Open Group’s own MK microkernel). Turbo-J only supports JVMs that comply with Sun Microsystems Inc specifications, including the JNI Java Native Interface, therefore it doesn’t work with Windows 95, NT or Internet Explorer. Open Group says Turbo- is especially suited to compiling Java servers and other large applications which will be constantly re-used. Written in Java, Open Group says Turbo-J requires 16Mb to compile itself while a large application such as HotJava will require 32Mb. A JDK 1.2 version is planned and work on a next-generation implementation has already begun. Open Group is positioning Turbo-J as a native installation compiler for the type of Java bytecode applications it thinks will soon become popular with ISVs. Instead of downloading several megabytes of Java spreadsheet code and waiting for JIT compilation each time the spreadsheet is used Turbo-J compiles it once and stores in natively for re-use. Open Group says Turbo-J has evolved from its long-gestating Architecture Neutral Distribution Format ANDF project. Pricing will be announced when the product ships. Open Group says Aysmetrix’s SuperCede for Windows is similar to Turbo-J and well as Inria’s Harissa native Java compiler although the latter uses its own runtime, where Turbo-J uses the loader, memory allocation, garbage collection and multi-threading of the platform’s native JDK. á
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