How to set java system properties globally on OS X?

Question

Short story

I need a system level way to set the java.awt.headless property to true for all java invocations. That is, using -Djava.awt.headless=true is not an option, since java is being invoked from places I don't have access to (e.g. from within another tool written in Java/C/etc.)

Long story

I'm using a bunch of tools written in Java (specifically Adobe's Air ADT) that rely on AWT classes. When I run these tools on the console they work fine. But when I run them from an SSH session they fail with java.lang.InternalError: Can't connect to window server - not enough permissions. Googling around I found that setting java.awt.headless to true will fix the problem. It doesn't, and that's because ADT itself spawns children Java processes without -Djava.awt.headless=true.

Is there any system-level way to ensure this property is set whenever Java is invoked? Maybe some system awt property file or equivalent?

Worst case scenario I could try replacing /usr/bin/java with a shell script that adds this argument to "$@" but I'm hoping to avoid that. (Update: Just to ensure my theory is right, tried this shell script hack and it does solve the problem. Just hoping for a cleaner solution)

Montague

i guess you can accept your update as a valid answer. – Bedroll

Answer 1

It looks like support for JAVA_TOOL_OPTIONS environment variable was added to the Sun/Oracle JVM at least by Java 6. It is described in Java 8 documentation. I haven't tested but it appears to be in the OpenJDK too. This appears to be a more standardized solution than the other answers here.

I was able to solve the issue I encountered with:

JAVA_TOOL_OPTIONS=-Djava.awt.headless=true ant ...

This successfully propagated the property to Gradle build scripts (./gradlew) called from Ant. By comparison ant -Djava.awt.headless=true ... did not propagate the property to subprocesses. Found this solution originally described in a Gradle-related gist on github.

Bucko

Answer 2

Use _JAVA_OPTIONS instead of JAVA_OPTS. _JAVA_OPTIONS will get picked up automatically when you run java.

export _JAVA_OPTIONS=-Djava.awt.headless=true
adt ... 

I know this is true on OS X. This indicates that this may work on Windows and Linux, as well.

Alethiaaletta

Additional note _JAVA_OPTIONS is not really documented so use this with care. Better check the source code : jdk7 arguments, jdk8 arguments. Note this only an Oracle hotspot arguments, it won't work on other JVMs based on some other code. Azul Zulu should work as it is built from OpenJDK code. – Feel

Answer 3

Seems there's no standard way to do this. This is the best I could come up with:

1. Rename /usr/bin/java to /usr/bin/java.ori

2. Create the following /usr/bin/java replacement with 755 permissions:

   #!/bin/bash
   java.ori $JAVAOPT "$@"
   

   Then you can use the environment variable JAVAOPT to set global java options. These will also be propagated to any java subprocess that may be spawned:

   export JAVAOPT=-Djava.awt.headless=true
   adt ...
   

Montague