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Sun Jan 09 13:41:28 GMT 2022
From /weblog/java/features
Watch service, watch if directory changed - http://www.javacodegeeks.com/2012/02/java-7-watchservice.html Tips of using bytebuffer - http://worldmodscode.wordpress.com[..]2/14/the-java-bytebuffer-a-crash-course/ path : ..\.\Java.txt absolute path : C:\Users\WINDOWS 8\workspace\Demo\..\.\Java.txt canonical path : C:\Users\WINDOWS 8\workspace\Java.txt Read more: http://javarevisited.blogspot.com[..]getcanonicalpath-java.html#ixzz3A8Zya6YG Jump to a position of a file, inputstream.skip() is faster than reader.skip(), and reader.skip() is faster than randomAccessFile. Java & Files: An Introduction - https://www.marcobehler.com/guides/java-files Modern file input/output with Java: Going fast with NIO and NIO.2 - https://blogs.oracle.com[..]2-buffers-channels-async-future-callback
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Wed Jan 05 13:07:30 GMT 2022
From /weblog/java/tools
Generate a diff page forother toreview in HG - https://blogs.oracle.com/bondolo/entry/how_i_generate_a_webrev Introduce a tool to keep IDE code and webcontainer code in sync - http://techblog.bozho.net/?p=1246 Auto complete of IDEA is pretty cool - http://maciejwalkowiak.pl[..]aster-with-intellij-idea-live-templates/ use ctrl-w to select text - http://paulhammant.com[..]ins-ides-their-best-feature-is-control-w 7-new-tools-java-developers-should-know - http://blog.takipi.com/7-new-tools-java-developers-should-know/ Buggy App is a simple java application that simulates different performance problems like Memory Leak, OutOfMemoryError, CPU spike, thread leak, StackOverflowError, deadlock, unresponsiveness, … - https://blog.fastthread.io[..]buggy-app-simulate-performance-problems/ 13 Best Java Decompilers for Download and Online Use for Java Developers - https://www.javaprogramto.com/2021/11/java-decompiler.html Generate fake data - http://www.datafaker.net/
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Thu Dec 02 01:03:52 GMT 2021
From /weblog/java/performance
java -XX:+PrintFlagsFinal -version | findstr HeapSize , find out actual Xmx default in bytes - https://www.edureka.co[..]default-parameters-of-xms-and-xmx-in-jvm -XX:+PerfDisableSharedMem , prevent locking by sharedmem in linux - http://www.evanjones.ca/jvm-mmap-pause.html How linkedin turn the GC - http://engineering.linkedin.com[..]ughput-and-low-latency-java-applications Using generational & concurrent GC collector - http://www.javacodegeeks.com[..]/04/ibm-jvm-tuning-gencon-gc-policy.html Full VM option list : http://blogs.sun.com/roller/resources/watt/jvm-options-list.html, update for Java7 - http://nerds-central.blogspot.com[..]ot.com/2011/07/all-jvm-7-xx-options.html http://stas-blogspot.blogspot.com[..]ost-complete-list-of-xx-options-for.html A simplified list for some frequency use options - http://rdafbn.blogspot.com.au[..]rbage-collector-guidelines-and-tips.html HotSpot JVM garbage collection options cheat sheet - http://aragozin.blogspot.com[..]spot-jvm-garbage-collection-options.html http://www.oracle.com[..]va/javase/tech/vmoptions-jsp-140102.html An example and story about effect of difference VM parameter affecting the performance - http://www.javaspecialists.eu/archive/Issue191.html Clear the code cache automatically with -XX:+UseCodeCacheFlushing - http://blogs.amd.com[..]time-for-long-running-java-applications/ Discussion about -XX:MinHeapFreeRatio parameter - http://www.gossamer-threads.com[..]s.com/lists/lucene/java-user/44286#44286 The other detailed guide for VM parameters tuning - http://java.sun.com/j2se/1.5/pdf/jdk50_ts_guide.pdf Here is a more simple cookbook - http://java.sun.com/performance/reference/whitepapers/tuning.html A outdated (1.4) , compehensive but still not really too detailed, overview of various GC tuning - http://www.petefreitag.com/articles/gctuning/ Some say following VM parameter is good enough -server -Xmx -XX:+UseParallelGC http://blogs.sun.com[..]/page/binublog?entry=java_tuning_for_xml Some say is useful if you have huge memory -XX:+UseLargePages http://blogs.sun.com[..]dagastine?entry=java_se_tuning_tip_large Some say below parameter keep GC in low pause -XX:MaxGCPauseMillis=5000 Some say below parameter are very optimal -XX:+DisableExplicitGC -XX:+UseConcMarkSweepGC -XX:NewSize=1200m -XX:SurvivorRatio=16 http://www.theserverside.com[..]d.tss?thread_id=41258&ASRC=EM_NNL_347804 Some say those parameter is good -XX:+UseConcMarkSweepGC -XX:ParallelCMSThreads=1 -XX:+CMSIncrementalMode -XX:+CMSIncrementalPacing -XX:CMSIncrementalDutyCycleMin=0 -XX:CMSIncrementalDutyCycle=10 http://blog.mikiobraun.de/2010/08/cassandra-gc-tuning.html Just in case anyone is curious, the flags enabled by -XX:+AggressiveOpts in JDK 1.6.0_25 are: -XX:+EliminateAutoBox -XX:AutoBoxCacheMax=20000 -XX:BiasedLockingStartupDelay=500 -XX:+DoEscapeAnalysis -XX:+OptimizeStringConcat -XX:+OptimizeFill Generate dump with OOME - -XX:+HeapDumpOnOutOfMemoryError GC log sample of -XX:+UseConcMarkSweepGC -XX:PrintFLSStatistics=1 -XX:+PrintGCDetails - https://gist.github.com/1329783 A case study of tuning VM GC parameters - http://plumbr.eu[..]ld-you-trust-the-default-settings-in-jvm Explanation for few performance related VM parameters - http://www.techpaste.com[..]ine-options-jvm-performance-improvement/ Show the exact vm flag that java using - http://matthewkwilliams.com[..]/looking-inside-a-jvm-xxprintflagsfinal/ For G1GC - https://dzone.com[..]e-first-garbage-collector-tuning-flags-1 https://ionutbalosin.com[..]otspot-jvm-performance-tuning-guidelines
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Sun Jun 20 12:53:30 GMT 2021
From /weblog/java/features
URL handler - http://skife.org[..]ibrary/2012/05/14/java_url_handlers.html , UrlSchemeRegistry.register("dinner", DinnerHandler.class); Talking to Postgres Through Java 16 Unix-Domain Socket Channels - https://www.morling.dev[..]ugh-java-16-unix-domain-socket-channels/
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Wed Feb 24 03:49:26 GMT 2021
From /weblog/java/string
String.intern() is designed for constant strings, it's implemented in C/C++ in the hotspot core code, and it has a fixed-size hashmap of around 20K entries and if more than this number of strings are interned, the performance degrades linearly since there are hash collisions and the code has to search down linked lists. http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6988220 String.intern in Java 7 and 8 - http://java-performance.info/string-intern-in-java-6-7-8/ http://java-performance.info[..]-intern-java-6-7-8-multithreaded-access/ http://java-performance.info/string-intern-java-7-8-part-3/ Suggestion of improving string decoding - https://cl4es.github.io/2021/02/23/Faster-Charset-Decoding.html
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