JDK1.4 Could not lock System prefs

[David Chan]

My java program work fine in PC. Then, when I try to move it to Unix platform (JDK version: 1.4.0_02) and test the compatibility, it can work properly but shows following error message:
Jan 14, 2004 11:28:50 PM java.util.prefs.FileSystemPreferences$2 run
WARNING: Could not create system preferences directory. System preferences are unusable.
Jan 14, 2004 11:28:58 AM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock System prefs.Unix error code 2334152.
Jan 14, 2004 11:28:58 AM java.util.prefs.FileSystemPreferences syncWorld
WARNING: Couldn't flush system prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
Jan 14, 2004 11:29:28 AM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock System prefs.Unix error code 2334152.
Jan 14, 2004 11:29:28 AM java.util.prefs.FileSystemPreferences syncWorld
WARNING: Couldn't flush system prefs: java.util.prefs.BackingStoreException: Couldn't get file lock.
I have solved the problem by creating the missing directories and files under /etc:
Directory: /etc/.java/.systemPrefs
drwxr-xr-x 2 root other 512 Jan 14 12:26 .
drwxr-xr-x 3 root other 512 Jan 14 12:26 ..
-rw-r--r-- 1 root other 0 Jan 14 12:26 .system.lock
-rw-r--r-- 1 root other 0 Jan 14 12:26 .systemRootModFile
1. Can someone explain what purpose of above 2 files?
2. What APIs are they related to?
3. Should I document this in the installation note?
Thank you

David

[Mark Spritzler]

My question is why your code is trying to access System file properties anyway. I don't remember any requirements in the assignment asking for this feature.
What code is causing these errors? I'd probably remove them from your code.
The assignment is designed so you don't have to access OS files like that, so that you can simply move your application from one OS to another without any issues to deal with.
Mark

[David Chan]

This is a JDK bug!!!
I have tried to remove /etc/.java directory and run the test program.
import javax.swing.JFrame;

public class Test {
public static void main(String[] args) {
new JFrame().show();
}
}
It will appear the error message if run by JDK1.4, but when I change to use JDK1.3, that message does not appear again. Therefore, I am sure that there is no problem in my java code.
Since I use JDK1.4 to develop the program, I think it is better to add some information about this bug in the installation note because maybe not all graders know this bug.
For detail, refer this link:
Disable system preferences
David

[Andrew Monkhouse]

Hi David,
Perhaps you should upgrade to a later version of the JDK? I am using:

java version "1.4.2_03"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_03-b02)
Java HotSpot(TM) Client VM (build 1.4.2_03-b02, mixed mode)

on my Linux machine, and I could not replicate your problem. I also tried leaving your application running for 60 seconds to allow the timer to expire, and adding the code to allow a clean exit (rather than a ctrl-c).
I ensured that I do not have an /etc/.java directory nor do I have a ~/.java directory.
Regards, Andrew

[Jay Bromley]

Hello,
For what it's worth, I use

java version "1.4.2_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_02-b03)
Java HotSpot(TM) Client VM (build 1.4.2_02-b03, mixed mode)

and I can't replicate the problem.
Regards,
jb

[David Chan]

I have downloaded the latest JDK to compile the code, all OK. But I run the application, it failed. Please help.
When I type java -jar runme.jar, show the following error message:
Exception in thread "main" java.lang.UnsatisfiedLinkError: /opt/j2sdk1.4.2_03/jre/lib/sparc/motif12/libmawt.so
: ld.so.1: java: fatal: libXm.so.4: open failed: No such file or directory
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1560)
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1456)
at java.lang.Runtime.load0(Runtime.java:737)
at java.lang.System.load(System.java:811)
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1560)
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1477)
at java.lang.Runtime.loadLibrary0(Runtime.java:788)
at java.lang.System.loadLibrary(System.java:834)
at sun.security.action.LoadLibraryAction.run(LoadLibraryAction.java:50)
at java.security.AccessController.doPrivileged(Native Method)
at sun.awt.NativeLibLoader.loadLibraries(NativeLibLoader.java:38)
at sun.awt.DebugHelper.<clinit>(DebugHelper.java:29)
at java.awt.Component.<clinit>(Component.java:506)
at suncertify.RunMe.main(RunMe.java:22)
I have checked the directory /opt/j2sdk1.4.2_03/jre/lib/sparc/, there only have motif21 directory but have no motif12 directory.
My solarix version:
SunOS labppsms 5.6 Generic_105181-28 sun4u sparc SUNW,Ultra-80
JDK version:
java version "1.4.2_03"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_03-b02)
Java HotSpot(TM) Client VM (build 1.4.2_03-b02, mixed mode)

David