How to run JRE in server mode?

Question

While trying to resolve another problem, I noticed my AdoptOpenJDK JRE (build 11.0.6+10) was running in client mode on my Windows 10 desktop with 64 GB of RAM.

java.vm.name=OpenJDK 64-Bit Client VM
java.version=11.0.6
java.vendor=AdoptOpenJDK

Specifying -server in the VM arguments did not stop it from running in client mode. (I specified -server in the vmargs section of an Eclipse RCP *.ini file.) Neither did modifying jre/lib/jvm.cfg to specify -client IGNORE.

I was able to force it to run in server mode by removing the file jre\bin\client\jvm.dll. That feels like a hack.

Is there a recommended way to force server mode other than -server?

score 2 · Answer 1 · answered May 18 '20 at 16:42

2

To run the JVM in server mode, you can modify the Java Runtime Environment (JRE) to default to server. You can run Java applications using the server virtual machine by modifying the jvm.cfg file in your Java installation.

This file is located in C:\Program Files\Java\j2reXXX\lib\i386\on Windows and in /usr/java/j2reXXX/lib/i386/ on Linux.

Change the order of execution in the file from

-client KNOWN
-server KNOWN

to

-server KNOWN
-client KNOWN

Above one definitely works.

If you are using Windows then you can try doing registry change also. By default, these services start the JVM using system defaults. However, you might want to change these system defaults for your services.

answered May 18 '20 at 16:42

Varadharajan Damotharan

151
1
5

Ah, order is significant. I'll try that! – Andy Thomas May 18 '20 at 17:14
The install location of jvm.cfg for me on Windows is *~jre/lib*. – Andy Thomas May 18 '20 at 17:16
yeah. i think it's same. try editing the file as above – Varadharajan Damotharan May 18 '20 at 17:19
Didn't help; still running in client mode. It was already in the order (server,client). Tried copying it to i386 subdirectory. That didn't help either. – Andy Thomas May 18 '20 at 17:22
Strange! ok will start digging in more. May I know couple of things. JAVA_HOME value you set and your OS is 32 or 64bit. – Varadharajan Damotharan May 18 '20 at 17:46
JAVA_HOME is `C:\Program Files\AdoptOpenJDK\jdk-11.0.6.10-hotspot`. However, that's **not** the JRE that we install, run, have shown in the `java.home` system property. – Andy Thomas May 18 '20 at 18:46
i think you should edit the JRE which yo actually try to install right? By default services uses JAVA_HOME. i recommended to edit the jvm.cfg inside respective JRE you use. Also if you are using 64 bit, then please edit this path also ````lib\amd64\```` – Varadharajan Damotharan May 19 '20 at 06:26
Yes, I modified jvm.cfg inside the JRE installed alongside, and used by my application. – Andy Thomas May 19 '20 at 13:36

How to run JRE in server mode?

1 Answers1