[ http://issues.apache.org/jira/browse/DERBY-700?page=comments#action_12424948 ] Daniel John Debrunner commented on DERBY-700: ---------------------------------------------
Using system properties will require that every user running with the security manager grant a new permission in their policy file to allow setting these system properties. I thought an earlier discussion on the list had recommended not to use system properties this way. One issue with system properties is that how do atomically set and get the property, I think that is needed to perform locking? In your current patch, there is a window between where you get and set the property where another thread in a anoter class loader could come in and "lock" the database, resulting in two active derby instances connecting to the same database. I also don't understand why on getting the system property you are catching NullPointerException and IllegalArgumentException, how would these be thrown by System.getProperty()? > Derby does not prevent dual boot of database from different classloaders on > Linux > --------------------------------------------------------------------------------- > > Key: DERBY-700 > URL: http://issues.apache.org/jira/browse/DERBY-700 > Project: Derby > Issue Type: Bug > Components: Store > Affects Versions: 10.1.2.1 > Environment: ava -version > java version "1.4.2_08" > Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_08-b03) > Java HotSpot(TM) Client VM (build 1.4.2_08-b03, mixed mode) > Reporter: Kathey Marsden > Assigned To: V.Narayanan > Priority: Critical > Fix For: 10.2.0.0 > > Attachments: DERBY-700.diff, DERBY-700.stat, DualBootRepro.java, > DualBootRepro2.zip > > > Derby does not prevent dual boot from two different classloaders on Linux. > To reproduce run the program DualBootRepro with no derby jars in your > classpath. The program assumes derby.jar is in 10.1.2.1/derby.jar, you can > change the location by changing the DERBY_LIB_DIR variable. > On Linux the output is: > $java -cp . DualBootRepro > Loading derby from file:10.1.2.1/derby.jar > 10.1.2.1/derby.jar > Booted database in loader [EMAIL PROTECTED] > FAIL: Booted database in 2nd loader [EMAIL PROTECTED] > On Windows I get the expected output. > $ java -cp . DualBootRepro > Loading derby from file:10.1.2.1/derby.jar > 10.1.2.1/derby.jar > Booted database in loader [EMAIL PROTECTED] > PASS: Expected exception for dualboot:Another instance of Derby may have > already booted the database D:\marsden\repro\dualboot\mydb. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
