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DCEVM and Hotswap enable rapid turnaround by allowing almost any class change to the running VM. It offers an experience very similar to JRebel for WebObjects developers. With this tool, you usually do not have to restart your application after code change.

DCEVM and Hotswap Agent for Java 17

JRE patched with the DCEVM

The Jetbrains JDK releases are unofficial but they provide JREs patched with the DCEVM. They are available at . These instructions were tested with Release 17_0_1-b164.4, architecture osx-x64, JBR with JCEF (DCEVM) , jbr  and jbrsdk. They should also work with architecture osx-aarch64.

curl -OL curl -O
tar -zxf jbrsdk_dcevm-17_0_1-osx-x64-b164.4.tar.gz
sudo mv jbrsdk /Library/Java/JavaVirtualMachines/jbrsdk_dcevm-17_0_1-osx-x64-b164.4

Hotswap Agent

Copy the latest version of Hotswap Agent from

curl -OL
sudo mkdir /Library/Java/JavaVirtualMachines/jbrsdk_dcevm-17_0_1-osx-x64-b164.4/Contents/Home/lib/hotswap
sudo mv hotswap-agent-1.4.2-SNAPSHOT.jar /Library/Java/JavaVirtualMachines/jbrsdk_dcevm-17_0_1-osx-x64-b164.4/Contents/Home/lib/hotswap/hotswap-agent.jar

Install in Eclipse 2021-09

In "Help > Eclipse Marketplace" install "Java 17 Support for Eclipse 2021-09 (4.21)" (Don't need patch sources). This should not be needed for Eclipse 2021-12.

In "Eclipse > Preferences > Java > Installed JREs" click [Add...] (next) [MacOS X VM] (next) 

    JRE Home: /Library/Java/JavaVirtualMachines/jbrsdk_dcevm-17_0_1-osx-x64-b164.4/Contents/Home

    JRE name: jetbrains dcevm 17

    Default VM arguments: -XX:HotswapAgent=fatjar --add-exports=java.base/


DCEVM and Hotswap Agent for Java 8


  • A JRE patched with the DCEVM
  • The Hotwsap agent to handle the WebObjects caches.


To enable HotSwap for all java launches, go to Installed JREs in Eclipse Preferences, select your active JRE and click Edit...


Add the following text to the Default VM arguments: