JRockit JVM versus HotSpot JVM

Question

If anyone can give me brief information about the advantages and disadvantages of the two JVM since they all depend on the Standard JVM Specification.

Answer 1

JRockit was originally developed by Appeal and BEA Systems before being acquired by Oracle to run server software.¹ It was meant to be optimized for large applications requiring long running tasks, a lot of memory and a scalable environment, pushing optimizations for these scenarios even further than the Sun HotSpot JVM in server-mode (see also: Real differences between "java -server" and "java -client"?).

Since the acquisition of Sun Microsystems by Oracle, Oracle has communicated on a concrete plan and roadmap to have JRockit and the HotSpot JVM to converge to be a "best of both worlds" implementation, mostly built on HotSpot but integrating the most popular features of JRockit.

In fact, and as mentioned on the same blog, JRockit won't be released as a Java 7 JVM; and some of JRockit's features are being incrementally brought into HotSpot (internally even sometimes now referred to as "HotRockit").

For more details, read:

• Differences Between BEA JRockit SDK and Sun HotSpot SDK
• Differences between JVM implementations

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^{1 As partially pulled from Wikipedia on March 3, 2012 at 1.50PM EST.}