Passing an entire file to JVM arguments

Question

I have several systems that all need to load the same properties to the JVM. I can use the -D flag to load one property at a time, but i am looking for something that will load

Answer 1

If you use Ant to lanuch the Java process, 9000's answer (plus his windows comment) will work, and you can have the launcher deal with the OS difference.

There is a StackOverflow thread here which describes how to determine the OS from ant

Answer 2

Some options:

1. Wrap your properties in your .jar file and then get your processes to read that properties file from getClass().getResourceAsStream()
2. Write a batch file to execute your Java processes, and either explicitly list the -D options, or create the command line dynamically.

I solve this problem normally by using Spring (used for other reasons too) and a PropertyPlaceholderConfigurer. That allows me to specify one or more locations for property files and modifies the Spring configuration in-place.

Answer 3

I don't think you can do that via the command line (without some bash hacks, perhaps), but you definitely can do that programatically:

Simply set one property -DmyPropertiesFile=/your/properties/file.properties and then read that with one of the Properties.load() overloads. After that, System.setProperties(yourProps) should do what you expect.

Of course, this requires that you can hook this code early enough so that your properties will be available when needed (For instance, if the main() method is yours, this is perfect).

Answer 4

That's roughly how we do it:

java $(tr '\n' ' ' < options_file) other args...

Here options_file contains ready -Dsomething or -Xsomething values, one per line. The tr command just replaces every newline with a space.