Question

Considering the following command line

java -Xms128m -Xms256m myapp.jar

Which settings will apply for JVM Minimum memory (Xms option) : 128m or 256m ?

Answer 1

Depends on the JVM, perhaps the version…perhaps even how many paper clips you have on your desk at the time. It might not even work. Don’t do that.

If it’s out of your control for some reason, compile and run this the same way you’d run your jar. But be warned, relying on the order of the options is a really bad idea.

public class TotalMemory
{
    public static void main(String[] args)
    {
         System.out.println("Total Memory: "+Runtime.getRuntime().totalMemory());
         System.out.println("Free Memory: "+Runtime.getRuntime().freeMemory());
    }
}