carfield.com.hk

time.txt

2025-01-16T12:10:04Z

How difference platform implement nanoTime() - http://www.javacodegeeks.com[..]12/02/what-is-behind-systemnanotime.html http://stackoverflow.com[..]62/is-system-nanotime-completely-useless

Java timezone ID reference - http://david.uebelacker.ch[..]etrive-locale-and-timezone-from-request/ http://tutorials.jenkov.com[..]m/java-date-time/java-util-timezone.html

setTimeZone affects calls to set(), but doesn’t change the existing Calendar time? So if we wanted to change the time zone we are working with, we have to adjust all the time fields too…but a SimpleDateFormatter still would show it as the current time zone. - http://keyholesoftware.wordpress.com[..]1/joda-time-the-future-of-java-datetime/

http://blog.joda.org[..]va-time-jsr-310-enhancements-java-9.html

deep dive into measuring time in Java - dihttps:[..]g-time-from-java-to-kernel-and-back.html

CronScheduler - https://medium.com[..]r-for-external-interactions-cb7ce4a4f2cd

The Surprising Complexity Behind Time - http://blog.vanillajava.blog/2024/12/pre.html

gc.txt

2024-01-09T10:53:31Z

Debugging RAM: Java Garbage Collection - Java Heap Deep Dive, Part 1 - https://talktotheduck.dev[..]ge-collection-java-heap-deep-dive-part-1

Concurrent Marking in G1 - https://tschatzl.github.io/2022/08/04/concurrent-marking.html

What Should I Know About Garbage Collection as a Java Developer? - https://foojay.io[..]t-garbage-collection-as-a-java-developer

JDK 21: The GCs keep getting better - https://kstefanj.github.io[..]/jdk-21-the-gcs-keep-getting-better.html

Thread.txt

2023-09-06T13:46:21Z

An API to get the state of a thread, but someone say it is not reliable - http://java.sun.com[..]5.0/docs/api/java/lang/Thread.State.html http://java.silke-wingens.de/2011/03/13/threads-states/?lang=en

http://www.nabble.com[..]readed-programs-tf3627394.html#a10128844

Having said that, I have to note that using Thread#getState() is not
something you can absolutely rely on as the behavior isn't guaranteed
to be the same on all platforms. That is, it can be a useful tool for
debugging and test-driving but not ideal for regression (unit)
testing.

Overview of Java thread - http://java67.blogspot.hk[..]t-thread-and-javalangthread-in-java.html

Loom - https://webtide.com/do-looms-claims-stack-up-part-1/ https://webtide.com/do-looms-claims-stack-up-part-2/

How will we debug Loom applications? - https://www.reddit.com[..]drv/how_will_we_debug_loom_applications/

Question: Why exactly are fibers cheaper than platform threads? - https://www.reddit.com[..]ion_why_exactly_are_fibers_cheaper_than/

Handling Virtual Threads - https://dzone.com/articles/handling-virtual-threads

1. Avoid Synchronized Blocks/Methods
2. Avoid Thread Pools To Limit Resource Access
3. Reduce ThreadLocal Usage
https://dzone.com[..]o-avoid-when-switching-to-virtual-thread

Exploring the design of Java’s new virtual threads - https://blogs.oracle.com/javamagazine/post/java-virtual-threads

profiler.txt

2023-07-01T14:23:08Z

http://java-performance.info/introduction-jmh-profilers/

Another blog of discussion of difference profiler - http://blog.orange11.nl/2012/03/13/java-profiler-comparison/

Introduction to jmap, visualvm and btrace - http://www.infoq.com/articles/java-profiling-with-open-source

JMP http://www.khelekore.org/jmp/ is an easy to setup and provide real time data choice. However it will crash JVM occasionally. So may be the one using web interface is better for us: http://oss.metaparadigm.com/jmemprof/

Articles -
Onjava - http://www.onjava.com/lpt/a/6689
Eclipsecolorer profiler, however that plugin require you install binary yourself, somehow tedious if you move from one machine to another machine - http://www.theserverside.com[..]tss?l=EclipseProfiler&asrc=EM_NLN_476666

A total java version of profiler!!: http://jiprof.sourceforge.net

Few other profiler haven't get time to try:
Free:
http://jcoverage.sourceforge.net/
http://www.tagtraum.com/gcviewer.html
http://profiler4j.sourceforge.net/
http://www.jamonapi.com

Eclipse plugin:
http://jmechanic.sourceforge.net/
http://eclipsecolorer.sourceforge.net/index_profiler.html
http://www.eclipse.org/mat/

Need $$:
http://www.ej-technologies.com/products/jprofiler/overview.html

See if the information useful.

How to measure with less than milli second - http://www.rationaljava.com[..]15/10/measuring-microsecond-in-java.html

Unleash the Power of Open Source Java Profilers: Comparing VisualVM, JMC, and async-profiler - https://www.infoq.com/articles/open-source-java-profilers/ https://www.infoq.cn/article/yO6pjms5izsxK5YrZ036

agent.txt

2023-05-04T12:27:29Z

http://www.takipioncode.com[..]1/07/double-agent-java-vs-native-agents/

List the pros of using native agent - http://apmblog.compuware.com[..]-for-application-performance-management/

Writing a Profiler in 240 Lines of Pure Java - https://mostlynerdless.de[..]ng-a-profiler-in-240-lines-of-pure-java/

security.txt

2023-04-21T23:07:50Z

Introduction to Java Encryption/Decryption - https://dev.java/learn/security/intro/

Java Serialization Filtering: Prevent 0-day Security Vulnerabilities - https://foojay.io[..]g-prevent-0-day-security-vulnerabilities

Using JCE with OpenSSL - http://kasparov.skife.org[..]ive/src/java/jce-openssl-redux.writeback

---------- Forwarded message ----------
From: "cab"
To:
Date: 10 Mar 2005 23:33:16 +0800
Subject: Re: CRC-32


java.util.zip.CRC32   crc32  =  new java.util.zip.CRC32();
crc32.update(byteArray);
long crcValue = crc32.getValue();

"Day Chan" 撰寫於郵件新聞:4230a15b$3@newsgroup.com.hk...
> Does anyone know how to calculate CRC-32 in Java?
> Thanks~

memory.txt

2023-04-20T13:08:46Z

Will you get any performance improvement if you manage memory yourself? - http://mentablog.soliveirajr.com[..]ne-is-faster-java-heap-or-native-memory/

More heap, GC will get slower - http://plumbr.eu[..]ing-heap-size-beware-of-the-cobra-effect

Collection of tools to analysis GC activities - http://www.fasterj.com/tools/gcloganalysers.shtml

Another presentation of performance hint for hotspot or memory - http://www.infoq.com/presentations/Extreme-Performance-Java

Show how to enable and analyze the verbose:gc out data - http://javaeesupportpatterns.blogspot.com.au[..]3/01/java-verbose-gc-tutorial-video.html

Discussion and comparison of difference GC at Java 1.7 - http://mechanical-sympathy.blogspot.com.au[..]7/java-garbage-collection-distilled.html . And here is the detail experiment among those difference GC, look like G1 is quite promising - http://java-is-the-new-c.blogspot.com.au[..]ng-and-benchmarking-java-7s-garbage.html

Memory is not allocate to single block, thus even you allocate enough memory in term of size, it may not enough to held individual object - https://plumbr.eu/blog/outofmemoryerror-on-overprovisioned-heap

Introduction to metaspace - http://www.infoq.com/articles/Java-PERMGEN-Removed

http://vanillajava.blogspot.com.au[..]optimising-memory-consumption-first.html

Some comments about System.gc() - http://jeremymanson.blogspot.com[..]om/2015/12/why-i-dont-like-systemgc.html

http://blog.takipi.com[..]ng-your-java-garbage-collection-overhead

Logging stop-the-world pauses in JVM - https://plumbr.eu[..]log/logging-stop-the-world-pauses-in-jvm

Why we should put difference app in same VM - http://mydailyjava.blogspot.hk[..]0/generational-disparity-in-garbage.html

Atlassian GC tuning guide - https://confluence.atlassian.com[..]ollection-gc-tuning-guide-461504616.html

Using jemalloc to get to the bottom of a memory leak - https://gdstechnology.blog.gov.uk[..]c-to-get-to-the-bottom-of-a-memory-leak/

Troubleshooting-Java-Memory-Issues - https://www.infoq.com/articles/Troubleshooting-Java-Memory-Issues

Useful parameters for OOME - https://jaxenter.com/jvm-outofmemoryerror-161257.html

Why Java's TLABs are so important and why write contention is a performance killer in multicore environments - https://www.opsian.com/blog/jvm-tlabs-important-multicore/

MMU gang wars: the TLB drive-by shootdown - http://bitcharmer.blogspot.com/2020/05/t_84.html

Latency implications of virtual memory - https://rigtorp.se/virtual-memory/

foreign-memaccess - http://cr.openjdk.java.net[..]cimadamore/panama/foreign-memaccess.html

Detect proactively whether application’s memory is under-allocated - https://jaxenter.com/memory-under-allocated-176329.html

Panama: Not-so-Foreign Memory. Using MemorySegment as a high-performance ByteBuffer replacement without a 2GB limit. - https://gavinray97.github.io/blog/panama-not-so-foreign-memory https://www.reddit.com[..]soforeign_memory_using_memorysegment_as/

What’s the deal with humongous objects in Java? - https://devblogs.microsoft.com[..]-the-deal-with-humongous-objects-in-java

Netflix on Java: How to build a 1TB Non-Heap, ultra-efficient application for video streaming - an example - https://dac.digital[..]on-heap-application-for-video-streaming/

mqtt.txt

2023-03-18T12:52:17Z

一文带你掌握物联网 Mqtt 网关搭建背后的技术原理 - https://xie.infoq.cn/article/15d34a2d1042101d319261da8

threadlocal.txt

2023-03-08T12:44:43Z

There is a little bit performance cost for threadlocal variable - http://software.intel.com[..]ost-of-accessing-thread-local-variables/

Look like a useful but less known API - http://crazybob.org/2006/07/hard-core-java-threadlocal.html

Forward up discussion - http://www.theserverside.com[..]d_id=41473&asrc=EM_NNL_406677&uid=703565 pointing out some problems of using this technique, include similar effect of GLOBLE , possible memory leak

Another discussion in higher level - http://blog.objectmentor.com[..]04/thread-local-a-convenient-abomination , Key is "An object is an abstraction of function. A thread is an abstraction of schedule" , you can read further conclusion at http://www.infoq.com/news/2007/09/confusing_uow_with_threads

Protential issue of using threadlocal, one is memory leak and the other is it is that local - http://blog.maxant.co.uk/pebble/2008/09/23/1222200780000.html http://www.javacodegeeks.com[..]hreading-stories-threadlocal-in-web.html
http://plumbr.eu[..]shoot-yourself-in-foot-with-threadlocals

The beauty of the design of threadlocal, how it prevent locking and memory leaking - http://plumbr.eu/blog/how-is-threadlocal-implemented

JEP 429: Extent-Local Variables to Promote Immutability in Java - https://www.infoq.com/news/2022/09/extent-local-variables-java/

An Introduction to Scoped Values in Java - https://foojay.io/today/an-introduction-to-scoped-values-in-java/

optional.txt

2023-03-08T12:38:40Z

The Beauty of Java Optional and Either - https://dzone.com/articles/the-beauty-of-java-optional-and-either

language related.txt

2023-03-07T13:15:18Z

Recursion solution can be faster than iterative solution - http://www.ahmadsoft.org/articles/recursion/index.html

Java 21: Performance Improvements Revealed - https://minborgsjavapot.blogspot.com[..]01/java-21-performance-improvements.html https://minborgsjavapot.blogspot.com[..]k-21-image-performance-improvements.html

type.txt

2023-02-17T11:55:07Z

Autoboxing, Type can be changed - http://blog.jooq.org/2013/10/08/java-auto-unboxing-gotcha-beware/

Project Valhalla: A look inside Java’s epic refactor - https://www.infoworld.com[..]a-a-look-inside-javas-epic-refactor.html

memory.txt

2023-02-15T13:22:38Z

How to use Eclipse Memory Analyzer - http://eclipsesource.com[..]s-for-using-the-eclipse-memory-analyzer/

Tool to check java memory layout, how the object placed in JVM - http://openjdk.java.net/projects/code-tools/jol/

Question: How do you handle oversized heap analysis? - https://www.reddit.com[..]w_do_you_handle_oversized_heap_analysis/

JVM Field Guide: Memory - https://serce.me/posts/01-02-2023-jvm-field-guide-memory

java19.txt

2023-02-08T13:19:36Z

Structured Concurrency and Loom - https://www.loicmathieu.fr[..]ss/en/informatique/java-19-quoi-de-neuf/

Using Pattern Matching - https://dev.java/learn/pattern-matching

vector.txt

2022-12-10T12:45:08Z

FizzBuzz – SIMD Style! - https://www.morling.dev/blog/fizzbuzz-simd-style/

SIMD accelerated sorting in Java - how it works and why it was 3x faster - https://jbaker.io/2022/06/09/vectors-in-java/

pandas.txt

2022-08-02T13:15:30Z

Kotlin DataFrame Preview - https://blog.jetbrains.com[..]022/06/kotlin-dataframe-library-preview/

constructor.txt

2022-08-02T12:39:29Z

Things I didn't know about Java: Generic Constructors - https://www.objectos.com.br/blog/java-generic-constructors.html

image.txt

2022-07-06T13:31:29Z

Strategies of loading image, select difference API to load image in difference case - http://java.sun.com[..]rticles/Media/imagestrategies/index.html

The Perils of Image.getScaledInstance() , with more detail explanation of image handling - http://today.java.net[..]3/perils-of-image-getscaledinstance.html

In Part I we talk about the building blocks of metadata in images and how it may matter to you as developer. - https://hillert.com/blog/read-write-image-metadata-java-part-1/

data.txt

2022-05-22T12:36:05Z

Data in Java programs - a basic conceptual model - https://docs.google.com[..]TscD4uW2Qsbt5BlBR_7uX_BekwJ5BLSE/preview

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/

collection.txt

2022-04-25T00:31:35Z

Performance comparison for various implementation - http://java-performance.info[..]-sachs-hppc-koloboke-trove-january-2015/

Java Hashtable, HashMap, ConcurrentHashMap – Performance impact - https://blog.fastthread.io[..]ap-concurrenthashmap-performance-impact/

http://marxsoftware.blogspot.com/2015/12/discovering-trove.html

Using Red-Black tree in Map - https://dzone.com[..]shmaps-keys-and-the-comparable-interface

scalability.txt

2022-04-15T12:54:04Z

1,000,000 Concurrent Connections - https://josephmate.github.io/2022-04-14-max-connections/

applet related.txt

2022-03-29T05:39:05Z

Workaround with sandbox - http://imagingexperts.typepad.com[..]ing_experts/2006/10/javascripting_i.html

Help running old Java applets in Windows 11 / Chrome - https://www.reddit.com[..]ng_old_java_applets_in_windows_11_chrome

hash.txt

2022-03-29T05:28:14Z

JVM Anatomy Quark #26: Identity Hash Code - https://shipilev.net/jvm/anatomy-quarks/26-identity-hash-code

Hash, displace, and compress: Perfect hashing with Java - https://www.andreinc.net/2022/03/15/perfect-hashing-with-java

Interrupt.txt

2022-03-19T12:00:19Z

Just know that interrupt() call is just setting a flag, it have to be doing IO work (like database call), or in wait() status, before the thread can really be interrupted.

http://blogs.sun.com[..]winger?entry=swingworker_stop_that_train

Another nice explanation about interrupt, in summary:

What should we do when we call code that may cause an InterruptedException? Don't immediately yank out the batteries! Typically there are two answers to that question:
1) Rethrow the InterruptedException from your method. This is usually the easiest and best approach. It is used by the new java.util.concurrent.* package [ http://java.sun.com[..]util/concurrent/Semaphore.html#acquire() ], which explains why we are now constantly coming into contact with this exception.
2) Catch it, set interrupted status, return. If you are running in a loop that calls code which may cause the exception, you should set the status back to being interrupted. For example:

while (!Thread.currentThread().isInterrupted()) {
  // do something
  try {
    TimeUnit.SECONDS.sleep(1000);
  } catch (InterruptedException e) {
    Thread.currentThread().interrupt();
    break;
  }
}

Remember the Law of the Sabotaged Doorbell - don't just ignore interruptions, manage them properly!

- http://www.javaspecialists.eu/archive/Issue146.html

Another blog explain about InterruptedException - http://www.nurkiewicz.com[..]terruptedexception-and-interrupting.html

http://ocpsoft.org[..]running-infinite-java-regular-expression

http://praveer09.github.io[..]derstanding-thread-interruption-in-java/

How to Stop a Java Thread Without Using Thread.stop()? - https://4comprehension.com[..]a-java-thread-without-using-thread-stop/