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"));