Recent Notes

Displaying keyword search results 51 - 60
Created by Dr. Xi on January 14, 2010 00:28:27    Last update: March 30, 2011 15:37:44
A task that a Java developer does so frequently is to find out where a certain class can be found - to resolve compilation errors, classpath issues, or version conflicts of the same class introduced by multiple class loaders. A long while back I wrote a simple Perl script to perform the task. Later I was informed that there are Swing based Jar Browser and Jars Browser . Then, there are a couple of shell one-liners: # one liner 1 find -name "*.jar" -print0 | xarg... But all of them share the same problem: if a class is in a jar nested in another jar, it cannot be found. Such is the case for a class inside a jar under the WEB-INF/lib directory of a...
Created by Dr. Xi on March 30, 2011 13:43:05    Last update: March 30, 2011 13:45:27
Method 1 - use javap with verbose flag: $ javap HelloWorld -verbose | head Compiled fro... Method 2 - use a utility class: import java.io.*; import java.nio.ByteBuffer; ... According to the VM Spec , a Java class file has this structure: ClassFile { u4 magic; ...
Created by Dr. Xi on March 28, 2011 20:51:30    Last update: March 28, 2011 20:53:46
HTTP basic authentication is just Base64 encoded user name and password passed in as the Authorization header. So the following code works: // encode user name and password String credent... However, since JDK 1.2, there's a more Java friendly way: Authenticator.setDefault(new Authenticator() { ... Test code: import java.net.*; import java.io.*; pub...
Created by Dr. Xi on October 16, 2008 20:45:40    Last update: March 28, 2011 20:23:22
Java's built-in classes are way too complex/flexible for a simple protocol like HTTP. This is a wrapper to simplify HTTP GET and POST. import java.io.*; import java.net.*; imp... A simple test: import java.io.*; import java.util.*; ...
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 mak on March 04, 2011 14:17:32    Last update: March 04, 2011 14:18:35
To create a zipfile in python: Code: #!/usr/local/bin/python import zipfile #... Test unzip -l test.zip Archive: test.zip Lengt... To read a zipfile in python: Code: #!/usr/local/bin/python import zipfile #...
Created by James on March 03, 2011 21:48:52    Last update: March 03, 2011 21:48:52
Just another way to left zero-pad a string. function zeroPad(s, length) { if (s.length ...
Created by woolf on February 10, 2011 13:16:34    Last update: February 10, 2011 13:16:49
%PATH:str1=str2% would expand the PATH environment variable, substituting each occurrence of " str1 " in the expanded result with " str2 ". " str2 " can be the empty string to effectively delete all occurrences of " str1 " from the expanded output. " str1 " can begin with an asterisk, in which case it will match everything from the beginning of the expanded output to the first occurrence of the remaining portion of str1. %PATH:~10,5% would expand the PATH environment variable, and then use only the 5 characters that begin at the 11th (offset 10) character of the expanded result. If the length is not specified, then it defaults to the remainder of the variable value. If either number (offset or length) is negative,...
Created by nogeek on February 08, 2011 13:46:18    Last update: February 08, 2011 13:46:18
Simple Java code that does XSLT on an XML file. The transform results go to STDOUT. import java.io.*; import javax.xml.parsers....
Created by Dr. Xi on October 07, 2010 19:20:55    Last update: January 11, 2011 19:59:17
Like the string trim function, Firefox provides a native implementation for array map, IE doesn't. So we have to create our own map function for Array : if(typeof Array.prototype.map !== 'function') { ... Test page: <html> <head> <title>Array Map</...
Previous  2 3 4 5 6 7 8 9 10 11 Next