carfield.com.hk

classloading.txt

2022-05-03T14:08:30Z

Hint to prevent blocking of loadClass by using Thread.getContextClassLoader() - https://blog.fastthread.io[..]3/java-class-loading-performance-impact/

corner case.txt

2021-10-17T11:59:31Z

Corner case cheat sheet in Java - https://ge0ffrey.github.io[..]cornerCaseCheatSheet/cheatSheetJava.html

cglib.txt

2013-12-18T07:53:04Z

http://www.jroller.com[..]/20050506#java_dynamic_proxies_and_cglib

http://mydailyjava.blogspot.com.au[..]com.au/2013/11/cglib-missing-manual.html

preprocessor.txt

2013-12-05T05:16:04Z

Funny, using gcc preprocessor with java - https://gist.github.com/anonymous/7797380

Intrinsics.txt

2012-09-11T14:21:17Z

How JVM optimzate the code by understanding the intentional of programmer - http://bad-concurrency.blogspot.com.au[..]/arithmetic-overflow-and-intrinsics.html

cracking java.txt

2011-10-29T18:36:47Z

"hi there".equals("cheers !") == true
This is because in the JDK 1.3 SUN is caching the hash code so if it once is calculated, it doesn't get recalculated, so if the value field changes, the hashcode stays the same.

http://www.artima.com/forums/flat.jsp?forum=106&thread=4864

How to Modifying an Application without Modifying Its Source Code, with {-Xbootclasspath/p:} - http://www.ddj.com[..]M4OQSNDLPCKH0CJUNN2JVN?_requestid=186396

Override string! - http://www.javacodegeeks.com/2011/10/weird-funny-java.html

exception.txt

2009-07-26T17:08:14Z

How to get line number of specific stacktrace
private static void log(String prefix,
String message) {

StackTraceElement ste =
new Exception().getStackTrace()[2];

System.out.println("[" + prefix + "] " +
ste.getClassName() + "." +
ste.getMethodName() + "(" +
ste.getLineNumber() + "): " +
message);
}

http://jroller.com[..]0602#abusing_java_for_debugging_purposes

Annotation of using stacktrace - http://www.theserverside.com[..]m/news/thread.tss?thread_id=55238#312195

kill.txt

2008-03-17T17:25:28Z

if you do a “kill -3? of the java process id, it dumps a stack trace of every thread, including what locks it’s holding, to stdout. - http://blog.xcski.com[..]ie-says-kill-3-pid-is-my-new-best-friend

At windows, it is ctrl-break

quickstart.txt

2007-05-13T11:12:13Z

of various java server - http://www.learntechnology.net/content/main.jsp
of various java technology - http://www.javapassion.com/j2ee/index.html

jar.txt

2007-05-03T07:30:15Z

This should not really matter for deployment case, but for development which keep on restarting may be useful

http://ant.apache.org/manual/CoreTasks/jar.html#indexjars

Edit JAR in code - http://www.java-tips.org[..]og/java-se/how-to-modify-a-jar-file.html

Throws NULL.txt

2007-04-27T08:12:43Z

We can just

throw null;

in java, but probably not a good idea for most case

http://beanman.wordpress.com[..]hrowing-null-with-different-jvm-options/

Interesting and useless trick.txt

2007-02-15T09:34:38Z

change intern String: http://cretesoft.com/archive/newsletter.do?issue=014

limitation of string size, parameter list length, ... etc: http://javaspecialists.co.za[..]ive/newsletter.do?issue=059&locale=en_US and http://www.javaspecialists.co.za/archive/newsletter.do?issue=121
Related is Size limitation of Java String - http://www.oreillynet.com/lpt/wlg/6303

generating nullpointerexception from throw NULL: http://fishbowl.pastiche.org/2003/04/30/throwing_null

When no nullpointerexception when object is null: http://fishbowl.pastiche.org/2006/01/17/random_java_trivia

j2me.txt

2006-11-30T15:22:16Z

optimizing java class for j2me, look like just break all OO principle... http://blog.javia.org/?p=31

bitwise operation on boolean.txt

2006-11-11T10:03:05Z

bitwise operation on boolean

The solution to the puzzle is given in the Java Language Specification, chapter 15.22.2:
15.22.2 Boolean Logical Operators &, ^, and |
When both operands of a &, ^, or | operator are of type boolean, then the type of the bitwise operator expression is boolean.
For &, the result value is true if both operand values are true; otherwise, the result is false.
For ^, the result value is true if the operand values are different; otherwise, the result is false.
For |, the result value is false if both operand values are false; otherwise, the result is true.

http://beust.com/weblog/archives/000350.html

Someone mentioned that there is no boolean, byte and short in byte code level, all just integer
http://oddjava.com/?q=node/8

security.txt

2006-11-07T05:11:24Z

Prevent System.exit() being call - http://jroller.com/page/ethdsy?entry=disabling_system_exit Usually security manager forbid it

Cracking class files.txt

2006-07-12T08:09:26Z

No sure if that still valid, but look like encrypt class file don't help on protecting class.

http://www.javaworld.com[..]ld/javaqa/2003-05/01-qa-0509-jcrypt.html

trick for java 5.txt

2006-06-26T06:32:59Z

New look of resultset, WebRowSet, http://www.onjava.com/lpt/a/6633 , but I personally don't think this is something useful

Some information how using jmxagent: http://weblogs.java.net[..]nus/archive/2006/06/going_beyond_jd.html

Just come across a nice article that discuss about various new features of 1.5 and provide tips on how to use them: http://java.sys-con.com/read/171487_p.htm

Create collection quick

List programmingLanguages = CollectionUtils.newList("Java", "C++", "Ruby");

Or this:

Map langs = new HashMap(3) {{
put("Java", "Wicked");
put("C++", "Ok");
put("Ruby", "Interesting");
}};

http://www.theserverside.com/blogs/thread.tss?thread_id=37839

equals() at proxy generated instance.txt

2006-05-16T07:30:58Z

At least need to test on the interface level. And more complicate if you don't want to expose the internal structure to interface

http://www.javaspecialists.co.za/archive/newsletter.do?issue=126

java.util.Calendar.txt

2006-04-07T05:13:55Z

I don't know this before, and I don't know if this is the behaviour of all Calendar implementation or it is only GregorianCalendar do this...

Every time you call set, Calendar sets a flag internally which indicates that something has changed. For performance reasons, the time is not actually computed until a call to getTime() (and variants).

The problem is that you are setting two conflicting states before computing the time:

thisMonth.set(Calendar.DAY_OF_MONTH, 1);
thisMonth.set(Calendar.DAY_OF_WEEK, 1);

According to the JavaDoc:
"If fields conflict, the calendar will give preference to fields set more recently."

Thus, in the second case, the call to set DAY_OF_MONTH is ignored.

http://discuss.joelonsoftware.com/default.asp?joel.3.328034

beware of java inline.txt

2005-12-14T08:35:14Z

Usually java inline constant , this work fine most likely but sometime you will have surprise about this

http://www.cretesoft.com/archive/newsletter.do?issue=114
http://jroller.com/page/ee?entry=dependency_checking_of_javac
http://jroller.com/page/ee?entry=javac_s_inlining_revisited

find file in classpath.txt

2005-07-12T04:27:06Z

This is kind of useful to have a quick way to find file in classpath, see if some day really deploy to system I work on: http://jroller.com/page/mlconnor/20050708#code_to_find_files_on