1 Introduction

This document provides simple guidelines to help migrate applications from Oracle JRockit to HotSpot JVM. It contains sections for each component of the JVM system that describe the equivalents of those in both Oracle JRockit and HotSpot JVM, and also list the corresponding important JVM options of those components. It includes tables mapping the complete set of Oracle JRockit -X and -XX command-line options to the ones available in the HotSpot.

Heap Sizing

Note:

Some of the tools described in this document require a commercial license for use in production. To learn more about commercial features and how to enable them, see http://www.oracle.com/technetwork/java/javaseproducts/.

Heap Sizing

HotSpot has the same options as Oracle JRockit to set the initial and the maximum Java heap size.

Table 1-1 Heap Size

Option	Oracle JRockit	HotSpot
`-Xms`	Sets the initial and minimum size of the heap	Sets the initial and minimum size of the heap
`-Xmx`	Sets the maximum size of the heap	Sets the maximum size of the heap

When migrating from Oracle JRockit to HotSpot, the Java heap size should essentially remain the same.