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Created by Dr. Xi on March 02, 2011 11:39:18    Last update: March 09, 2011 12:19:30
Some peculiarities about Java PrintWriter: PrintWriter never throws any exceptions. From JavaDoc : Methods in this class never throw I/O exceptions, although some of its constructors may. The client may inquire as to whether any errors have occurred by invoking checkError(). When error occurs, you'll never know anything more than that it occured, because checkError returns boolean. When a character is out of the range of the character encoding of the PrintWriter, it prints a question mark (?). But this is not an error. Test code: import java.io.*; public class TestPrintWri... Latin1 test result: java TestPrintWriter iso-8859-1 | od -bc 000000... UTF-8 test result: java TestPrintWriter utf-8 | od -bc 0000000 141... Also, the constructor throws a FileNotFoundException when you try to write to a...
Created by voodoo on February 25, 2011 14:00:41    Last update: February 25, 2011 14:03:46
Suddenly my Windows XP failed to boot with this error message on a blank screen: missing or corrupt <windows root>\system32\hal.dll I took out the hard drive, put it in a USB enclosure and attached it to another PC. Then I ran CHKDSK and it fixed some file system errors. But I did find that hal.dll was intact, so hal.dll was not missing or corrupt . It turned out that the file that was really missing was C:\boot.ini . It is a hidden file, so you have to use attrib boot.ini to see it. The file is missing if attrib boot.ini returns nothing (run in the root folder C:\). In my case I reconstructed the boot.ini file: [boot loader] timeout=30 default=multi(0)dis... and changed the attributes back...
Created by magnum on August 19, 2010 22:42:26    Last update: August 19, 2010 22:43:59
Lyx wasn't able to open DVI files with the error message MIME type application/x-dvi not supported. I looked at Lyx preferences and it's using xdg-open to open the file. The following query shows that the default application for the DVI mime type is Evince. So I updated that to xdvi , which I do have. $ xdg-mime query default application/x-dvi ... But it didn't work! I checked that the file ~/.local/share/applications/defaults.list did get updated. I even logged out and logged back in! I had to update the system wide configuration file /usr/share/applications/defaults.list to make it work: #application/x-dvi=evince.desktop applicati...
Created by Fang on July 17, 2010 03:16:53    Last update: July 17, 2010 03:18:25
This error happens when the ordering of elements in web.xml is not correct. For example, in a <servlet> declaration, <servlet-name> should come before <servlet-class> . If you switch the order of <servlet-name> and <servlet-class> , you'll get this error. This was my stack trace in JBoss when I declared <load-on-startup> before <init-param> for a servlet: DEPLOYMENTS IN ERROR: Deployment "vfszip:/C:/...
Created by Dr. Xi on December 04, 2009 04:33:05    Last update: December 04, 2009 04:33:05
Variable Meaning $_ The default or implicit variable. @_ Within a subroutine the array @_ contains the parameters passed to that subroutine. $a, $b Special package variables when using sort() $<digit> Contains the subpattern from the corresponding set of capturing parentheses from the last pattern match, not counting patterns matched in nested blocks that have been exited already. $. Current line number for the last filehandle accessed. $/ The input record separator, newline by default. $| If set to nonzero, forces a flush right away and after every write or print on the currently selected output channel. Default is 0 (regardless of whether the channel is really buffered by the system or not; $| tells you only whether you've asked Perl explicitly to flush after...
Created by Dr. Xi on September 29, 2008 23:03:40    Last update: September 29, 2008 23:04:08
Variables set automatically by shell: Variable Description $# Number of command-line arguments. $- Options currently in effect (arguments supplied to sh or to set). $? Exit value of last executed command. $$ Process number of current process. $! Process number of last background command. $0 First word; that is, command name. $n Individual arguments on command line (positional parameters). The Bourne shell allows only nine parameters to be referenced directly (n = 1-9); the Korn shell allows n to be greater than 9 if specified as ${n}. $* All arguments on command line ("$1 $2..."). $@ All arguments on command line, individually quoted ("$1" "$2" ...). Variables set automatically by Korn shell: Variable Description ERRNO Error number of last system call that failed. LINENO Current...