OpenJDK 64 bit Java 1.6 : Doesn't support dot in CLI system properties?

Question

The version of Java is printed below:

$ java -version
java version "1.6.0_24"
OpenJDK Runtime Environment (IcedTea6 1.11.5) (6b24-1.11.5-0ubuntu1~12.04.1)
OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)

When passing a property like so:

java -Dmy.property=value -jar my.jar

..it fails to resolve in the code:

System.getProperty("my.property") // => null

However using an underscore in place of the dot works fine:

// CLI
java -Dmy_property=value -jar my.jar
// In the code:
System.getProperty("my_property") // => "value"

Isn't this non-standard behaviour?

In case it's relevant, the JAR is being built via Maven and the maven-assembly-plugin is being used to bundle dependencies into the JAR.

Answer 1

Initially I was using the improper format java -jar my.jar -Dmy.prop=value rather than the correct java -Dmy.prop=value -jar my.jar . But I realised this early on and amended my parameter ordering.

However, it turns out when editing the monolithic chain of commands I was editing (with this java -jar command in-line amongst them) I mistakenly created another incorrect command structure: java -jar -Dmy.prop=value my.jar .

The first time I used underscores the command was rewritten, thus inadvertently fixing this latter incorrect parameter structure.

So the moral of the story is: ensure you have -jar my.jar right at the end of your java command. Always!

Answer 2

Java supports dots in property names when you set them like that.

A couple of possible explanations:

• The actual command being executed is different to that. Maybe there's a bug in your launch script or something. (Try using "set -x" to get the shell to tell you what the actual command options are.)

• Some other part of your application is unsetting that particular property before the call to getProperty you are looking at.