Reading Java system properties from command line

Question

Is there a better way to print system properties from command line? As we can set the property e.g.

 java  -D=  //set a system property         


        

Answer 1

If you need defaults that your JVM will initially have set unless overridden, use:

java -XshowSettings:properties -version  

This is helpful if you don't have a Java application already running, thus no pid to pass to one of the other commands.

If you are seeking the properties of a JVM already running that has properties set via default or set explicitly by command, then use the pid for that JVM found via jps with the jcmd or jinfo commands as listed in answers above.