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Trava-jdk-11-dcevm

TravaOpenJDK11 is OpenJDK11 for developers. Since it is based on dcevm and integrated HotswapAgent, it allows advanced hotswap like method-field addition and many more. Trava is a build farm created and maintained by HotswapProjects. Build is transparent as much as possible. dcevm-11 source code is built on GitHub Actions and the produced JDK images are bundled with HotswapAgent. Building is exclusively based on modified AdoptOpenJDK scripts.

Install

Download windows/linux/macos binaries, unpack and set JAVA_HOME to it's location (or add it as JDK to your IDE).

News since Dcevm11.0.9

New JVM option -XX:HotswapAgent

Starting with dcevm-11.0.9 HotswapAgent is disabled by default. HotswapAgent support can be enabled now in 3 different modes:

• -XX:HotswapAgent=fatjar turns on internal fatjar HotswapAgent
• -XX:HotswapAgent=core turns on internal core HotswapAgent
• -XX:HotswapAgent=external setup HotswapAgent support in JVM and leaves settings of external HotswapAgent on user. User must supply hotswap-agent.jar using additional argument e.g. -javaagent:<path>/hotswap-agent.jar
• disabled - default value.

HotswapAgent=core mode has no plugins except of core JVM plugins. It is faster since less scanning tasks and less class copying are necessary to be done. Additional plugins must be configured as maven dependencies in pom.xml. In HotswapAgent=fatjar mode all plugins are available from start, it slows down application start little bit.

G1 garbage collector is default

Since dcevm11.0.9 G1 is default garbage collector, it improves compatibility with standard JDK. It is first necessary step to replace system JDK by dcevm in the future. Serial GC can be turn on by standard option -XX:+UseSerialGC

Configure

For HotswapAgent configuration look at hotswapagent.org. HotswapAgent support can be turned on using option -XX:HotswapAgent=[fatjar,core,external]

Additional Info

Changes in dcevm11

Starting with dcevm11 option -XXaltjvm=dcevm is not supported anymore. There is a full java-11-openjdk distribution instead of it.

Content

• java11-openjdk-dcevm-linux.tar.gz - linux x64 JDK binary bundled with latest SNAPHOT release of hotswap-agent.jar
• java11-openjdk-dcevm-windows.zip - windows x64 JDK binary bundled with latest SNAPHOT release of hotswap-agent.jar
• java11-openjdk-dcevm-osx.tar.gz - macos JDK binary bundled with latest SNAPHOT release of hotswap-agent.jar

HOWTO

Activate Serial GC

Use -XX:+UseSerialGC JVM option to turn on Serial garbage collector.

Fallback to standard redefinition

Use option -XX:-AllowEnhancedClassRedefinitionto disable advanced redefinition and switch JVM to standard redefinition (only in-method modifications are allowed)

Check distribution

hotswap@skybber ~ $ java -XX:HotswapAgent=fatjar -version
Starting HotswapAgent '/usr/lib/jvm/java-11-openjdk/lib/hotswap/hotswap-agent.jar'
HOTSWAP AGENT: 18:06:22.007 INFO (org.hotswap.agent.HotswapAgent) - Loading Hotswap agent {1.4.2-SNAPSHOT} - unlimited runtime class redefinition.
HOTSWAP AGENT: 18:06:22.221 INFO (org.hotswap.agent.config.PluginRegistry) - Discovered plugins: [Hotswapper, WatchResources, AnonymousClassPatch, ClassInitPlugin, JdkPlugin, Hibernate, Hibernate3JPA, Hibernate3, Spring, Jersey1, Jersey2, Jetty, Tomcat, ZK, Logback, Log4j2, MyFaces, Mojarra, Omnifaces, ELResolver, WildFlyELResolver, OsgiEquinox, Owb, Proxy, WebObjects, Weld, JBossModules, ResteasyRegistry, Deltaspike, GlassFish, Vaadin, Wicket, CxfJAXRS, FreeMarker, Undertow, MyBatis]
openjdk version "11.0.9" 2020-10-20
OpenJDK Runtime Environment (build 11.0.9+0)

With HotswapAgent disabled:

hotswap@skybber ~ $ java -version
openjdk version "11.0.9" 2020-10-20
OpenJDK Runtime Environment (build 11.0.9+0)
Dynamic Code Evolution 64-Bit Server VM (build 11.0.9+0, mixed mode)

Package info

• Newest HotswapAgent 1.4.1

Build your binaries!

It is not necessary to use supplied binaries, you can build your own binaries. It is simple and it can be done in several clicks:

• Fork this repository
• Go to Actions and run action manually
• or update push.yml, create a tagged commit, push changes and wait for GitHub Actions to build your binaries.

HOWTO deploy a new release

Release with existing TAG

• If repository has some updates since last tagged, then move tag:

    git push origin :refs/tags/${SOURCE_JDK_TAG}
    git tag -fa ${SOURCE_JDK_TAG}
    git push origin master --tags

• Cleanup binaries from Releases/
• Trigger tagged job

Release with new TAG

Let's jdk source repository has new tag of value TAGVAL

• Update variables dcevm_branch and dcevm_tag in push.yml to TAGVAL
• Commit and tag commit with TAGVAL
• Appropriate a new tagged job should be created on Travis automatically