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.
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://download.oracle.com/javase/6/docs/technotes/guides/jmx/.