If I specify a system property multiple times when invoking the JVM which value will I actually get when I retrieve the property? e.g.
java -Dprop=A -Dprop=B -jar my.jar
What will be the result when I call System.getProperty("prop");
?
The Java documentation on this does not really tell me anything useful on this front.
In my non-scientific testing on a couple of machines running different JVMs it seems like the last value is the one returned (which is actually the behavior I need) but I wondered if this behavior is actually defined officially anywhere or can it vary between JVMs?
System properties contain information to configure the JVM and its environment. Some system properties are particularly relevant for JVMs in a CICS® environment. Specify JVM system properties in the JVM profile.
You can pass Java system properties to Microservices Runtime by modifying the setenv. bat/sh file.
The directory server provides a means of configuring the Java Virtual Machine (JVM) and Java options for each command-line utility and for the directory server itself. The Java configuration is provided in a properties file, located at instance-dir /OUD/config/java.
Now let's discuss the most frequently used JVM Parameters which are 3 namely as follows: Java Heap Size. Garbage Collector. Print GC.
There's nothing like writing a little class to see how it works.
public class PropTest { public static void main(String[] args) { System.out.println(System.getProperty("prop")); } }
Which when compiled and ran with the command line
java -Dprop=A -Dprop=B -Dprop=C PropTest
yeilds the output
C
Which would imply that the values are put into the table left to right, with the last value overwriting previous values.
Just to make a note of the environment, Fedora 16, Linux 3.3.7, 64 bit
> java -version java version "1.6.0_24" OpenJDK Runtime Environment (IcedTea6 1.11.1) (fedora-65.1.11.1.fc16-x86_64) OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)
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