# Verifying system properties

You can find out the value of a system property if you set it programmatically. You cannot find out the value of a system property if you set it in the derby.properties file.

For example, if you set the value of the `derby.storage.pageSize` system-wide property in your program or on the command line, the following code will retrieve its value from the System Properties object:

    Properties sprops = System.getProperties();
    System.out.println("derby.storage.pageSize value: "
    + sprops.getProperty("derby.storage.pageSize"));

You can also use Java Management Extensions (JMX) technology to obtain system information, including some settings that correspond to system properties. For details, visit the wiki page http://wiki.apache.org/db-derby/DerbyJMX and refer to the API documentation for the packages org.apache.derby.mbeans and org.apache.derby.mbeans.drda. For information on JMX technology, see http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/

Parent topic: System-wide properties
Related concepts
Changing the system-wide properties programmatically
Changing the system-wide properties by using the derby.properties file