DCEVM allows you to inject your compiled java code whilst the application is at the running state just like JRebel but freeware.
Project site: https://dcevm.github.io/
Download: https://github.com/dcevm/dcevm/releases/
Hotswap download: https://github.com/HotswapProjects/HotswapAgent/releases
for this experiement you’ll need DCEVM and hotswap agent. Download all tools and follow my lead
1. Launch DCEVM jar and patch your corresponding JVM(mind your jvm version is compatible with the DCEVM given version)
2. Copy “hotswap-agent.jar” to a proper location, in the case to find it easily i located it in root C: drive
3.for maven projects go to environment variables and enter the below lines,
Variable Name: MAVEN_OPTS
Variable Value: -XXaltjvm=”dcevm” -javaagent:C:\hotswap-agent.jar
4.check whether the variable is good to set in command line(if it does not print the value shown below, it is good to restart your machine windows may not pick it up quickly)
echo %MAVEN_OPTS%
5.Launch your project, while your application is being kicked off, you’ll see outputs of howswap capturing the application
mvn clean tomcat7:run -Plocal-DskipTests
6. Implement a change while the application working, In the controller I’ve added a sysout to see the change rapidly
