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• Ignoring file 'eugenesan-java-quantal.list.save'

  - by Lupus

  I have a problem with my newly installed 12.10 86_64 Desktop. This error pops up on console when I try to update apt-get or try to install packages and nodejs just don't work and there is no error on console. Ignoring file 'eugenesan-java-quantal.list.save' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension this error started after my update on apt-get sudo apt-get update I'm a newbie on ubuntu. this is the log file : (in Turkish 'Yoksay' = Ignored, 'Baglandi' = Connected, 'getirilmesi basarisiz oldu' = failed to get ) attila@Lupuseum:~$ sudo apt-get update Yoksay http://security.ubuntu.com quantal-security InRelease Yoksay http://extras.ubuntu.com quantal InRelease Yoksay http://ppa.launchpad.net quantal InRelease Baglandi http://security.ubuntu.com quantal-security Release.gpg Baglandi http://extras.ubuntu.com quantal Release.gpg Yoksay http://cy.archive.ubuntu.com quantal InRelease Yoksay http://ppa.launchpad.net quantal InRelease Baglandi http://security.ubuntu.com quantal-security Release Baglandi http://extras.ubuntu.com quantal Release Yoksay http://cy.archive.ubuntu.com quantal-updates InRelease Baglandi http://ppa.launchpad.net quantal Release.gpg Baglandi http://security.ubuntu.com quantal-security/main Sources Yoksay http://cy.archive.ubuntu.com quantal-backports InRelease Baglandi http://extras.ubuntu.com quantal/main Sources Yoksay http://ppa.launchpad.net quantal Release.gpg Baglandi http://security.ubuntu.com quantal-security/restricted Sources Baglandi http://cy.archive.ubuntu.com quantal Release.gpg Baglandi http://extras.ubuntu.com quantal/main amd64 Packages Baglandi http://ppa.launchpad.net quantal Release Baglandi http://security.ubuntu.com quantal-security/universe Sources Baglandi http://cy.archive.ubuntu.com quantal-updates Release.gpg Baglandi http://extras.ubuntu.com quantal/main i386 Packages Yoksay http://ppa.launchpad.net quantal Release Baglandi http://cy.archive.ubuntu.com quantal-backports Release.gpg Baglandi http://ppa.launchpad.net quantal/main Sources Baglandi http://security.ubuntu.com quantal-security/multiverse Sources Baglandi http://cy.archive.ubuntu.com quantal Release Baglandi http://ppa.launchpad.net quantal/main amd64 Packages Baglandi http://security.ubuntu.com quantal-security/main amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates Release Baglandi http://ppa.launchpad.net quantal/main i386 Packages Baglandi http://security.ubuntu.com quantal-security/restricted amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports Release Baglandi http://security.ubuntu.com quantal-security/universe amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal/main Sources Baglandi http://security.ubuntu.com quantal-security/multiverse amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal/restricted Sources Baglandi http://security.ubuntu.com quantal-security/main i386 Packages Baglandi http://cy.archive.ubuntu.com quantal/universe Sources Baglandi http://security.ubuntu.com quantal-security/restricted i386 Packages Baglandi http://cy.archive.ubuntu.com quantal/multiverse Sources Baglandi http://security.ubuntu.com quantal-security/universe i386 Packages Baglandi http://cy.archive.ubuntu.com quantal/main amd64 Packages Baglandi http://security.ubuntu.com quantal-security/multiverse i386 Packages Baglandi http://cy.archive.ubuntu.com quantal/restricted amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal/universe amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal/multiverse amd64 Packages Baglandi http://security.ubuntu.com quantal-security/main Translation-en Yoksay http://extras.ubuntu.com quantal/main Translation-tr_CY Baglandi http://cy.archive.ubuntu.com quantal/main i386 Packages Baglandi http://cy.archive.ubuntu.com quantal/restricted i386 Packages Yoksay http://extras.ubuntu.com quantal/main Translation-tr Baglandi http://security.ubuntu.com quantal-security/multiverse Translation-en Baglandi http://cy.archive.ubuntu.com quantal/universe i386 Packages Yoksay http://extras.ubuntu.com quantal/main Translation-en Baglandi http://cy.archive.ubuntu.com quantal/multiverse i386 Packages Baglandi http://cy.archive.ubuntu.com quantal/main Translation-tr Baglandi http://cy.archive.ubuntu.com quantal/main Translation-en Baglandi http://security.ubuntu.com quantal-security/restricted Translation-en Baglandi http://cy.archive.ubuntu.com quantal/multiverse Translation-tr Baglandi http://cy.archive.ubuntu.com quantal/multiverse Translation-en Baglandi http://security.ubuntu.com quantal-security/universe Translation-en Baglandi http://cy.archive.ubuntu.com quantal/restricted Translation-tr Baglandi http://cy.archive.ubuntu.com quantal/restricted Translation-en Baglandi http://cy.archive.ubuntu.com quantal/universe Translation-tr Baglandi http://cy.archive.ubuntu.com quantal/universe Translation-en Baglandi http://cy.archive.ubuntu.com quantal-updates/main Sources Baglandi http://cy.archive.ubuntu.com quantal-updates/restricted Sources Baglandi http://cy.archive.ubuntu.com quantal-updates/universe Sources Baglandi http://cy.archive.ubuntu.com quantal-updates/multiverse Sources Baglandi http://cy.archive.ubuntu.com quantal-updates/main amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates/restricted amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates/universe amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates/multiverse amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates/main i386 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates/restricted i386 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates/universe i386 Packages Baglandi http://cy.archive.ubuntu.com quantal-updates/multiverse i386 Packages Yoksay http://ppa.launchpad.net quantal/main Translation-tr_CY Yoksay http://ppa.launchpad.net quantal/main Translation-tr Yoksay http://ppa.launchpad.net quantal/main Translation-en Baglandi http://cy.archive.ubuntu.com quantal-updates/main Translation-en Hata http://ppa.launchpad.net quantal/main Sources 404 Not Found Hata http://ppa.launchpad.net quantal/main amd64 Packages 404 Not Found Hata http://ppa.launchpad.net quantal/main i386 Packages 404 Not Found Baglandi http://cy.archive.ubuntu.com quantal-updates/multiverse Translation-en Yoksay http://ppa.launchpad.net quantal/main Translation-tr_CY Yoksay http://security.ubuntu.com quantal-security/main Translation-tr_CY Yoksay http://ppa.launchpad.net quantal/main Translation-tr Yoksay http://security.ubuntu.com quantal-security/main Translation-tr Yoksay http://ppa.launchpad.net quantal/main Translation-en Yoksay http://security.ubuntu.com quantal-security/multiverse Translation-tr_CY Baglandi http://cy.archive.ubuntu.com quantal-updates/restricted Translation-en Yoksay http://security.ubuntu.com quantal-security/multiverse Translation-tr Yoksay http://security.ubuntu.com quantal-security/restricted Translation-tr_CY Yoksay http://security.ubuntu.com quantal-security/restricted Translation-tr Baglandi http://cy.archive.ubuntu.com quantal-updates/universe Translation-en Yoksay http://security.ubuntu.com quantal-security/universe Translation-tr_CY Baglandi http://cy.archive.ubuntu.com quantal-backports/main Sources Yoksay http://security.ubuntu.com quantal-security/universe Translation-tr Baglandi http://cy.archive.ubuntu.com quantal-backports/restricted Sources Baglandi http://cy.archive.ubuntu.com quantal-backports/universe Sources Baglandi http://cy.archive.ubuntu.com quantal-backports/multiverse Sources Baglandi http://cy.archive.ubuntu.com quantal-backports/main amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/restricted amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/universe amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/multiverse amd64 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/main i386 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/restricted i386 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/universe i386 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/multiverse i386 Packages Baglandi http://cy.archive.ubuntu.com quantal-backports/main Translation-en Baglandi http://cy.archive.ubuntu.com quantal-backports/multiverse Translation-en Baglandi http://cy.archive.ubuntu.com quantal-backports/restricted Translation-en Baglandi http://cy.archive.ubuntu.com quantal-backports/universe Translation-en Yoksay http://cy.archive.ubuntu.com quantal/main Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal/multiverse Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal/restricted Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal/universe Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-updates/main Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-updates/main Translation-tr Yoksay http://cy.archive.ubuntu.com quantal-updates/multiverse Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-updates/multiverse Translation-tr Yoksay http://cy.archive.ubuntu.com quantal-updates/restricted Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-updates/restricted Translation-tr Yoksay http://cy.archive.ubuntu.com quantal-updates/universe Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-updates/universe Translation-tr Yoksay http://cy.archive.ubuntu.com quantal-backports/main Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-backports/main Translation-tr Yoksay http://cy.archive.ubuntu.com quantal-backports/multiverse Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-backports/multiverse Translation-tr Yoksay http://cy.archive.ubuntu.com quantal-backports/restricted Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-backports/restricted Translation-tr Yoksay http://cy.archive.ubuntu.com quantal-backports/universe Translation-tr_CY Yoksay http://cy.archive.ubuntu.com quantal-backports/universe Translation-tr N: Ignoring file 'eugenesan-java-quantal.list.save' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension W: http://ppa.launchpad.net/richarvey/nodejs/ubuntu/dists/quantal/main/source/Sources 404 Not Found getirilmesi basarisiz oldu W: http://ppa.launchpad.net/richarvey/nodejs/ubuntu/dists/quantal/main/binary-amd64/Packages 404 Not Found getirilmesi basarisiz oldu W: http://ppa.launchpad.net/richarvey/nodejs/ubuntu/dists/quantal/main/binary-i386/Packages 404 Not Found getirilmesi basarisiz oldu E: Some index files failed to download. They have been ignored, or old ones used instead.

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• Diagnosing Solaris 8 server memory and swap space usage

  - by datSilencer

  Hello everyone. Essentially, my question is related to memory allocation for Solaris virtual machines. I am running a couple of old Sun ONE 6 Java web servers on two Solaris 8 virtual machines. I see that there's a reasonable amount of swap space being used, but I'm not exactly sure if this could indicate a need to add more RAM to these machines. At service peak hours (mornings usually), the response time of the web application these servers host jumps up to at most 11 seconds (somewhat detrimental for a relatively simple web page loading action). Average response time at non peak times is about 5 seconds. What would you be able to infer about the RAM usage for these machines from the ouput below? Is this information reasonably sufficient? Or would I need to run some other commands to rule out server memory starvation? Finally, since there is a Java application at the core of the setup, I've also thought about: 1) Trace the heap's Object allocation to detect potential memory leaks. 2) Do some performance profiling to see if this instead related to networking delays. I mention this since the application talks with a single Oracle Database, but I would doubt this to be the case since they're pretty close from a network segmentation perspective. I appreciate any kind of insight and feedback you could provide. Thanks for your time and help. Server 1: 40 processes: 38 sleeping, 1 zombie, 1 on cpu CPU states: 99.1% idle, 0.4% user, 0.4% kernel, 0.0% iowait, 0.0% swap Memory: 2048M real, 295M free, 865M swap in use, 3788M swap free PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND 12676 webservd 112 29 10 616M 242M sleep 103:37 0.48% webservd 18317 root 1 59 0 23M 19M sleep 67:24 0.08% perl 9479 support 1 59 0 6696K 2448K cpu/1 0:11 0.05% top 8012 root 10 59 0 34M 704K sleep 80:54 0.04% java 1881 root 33 29 10 110M 13M sleep 33:03 0.02% webservd 7808 root 1 59 0 83M 67M sleep 7:59 0.00% perl 1461 root 20 59 0 5328K 1392K sleep 6:49 0.00% syslogd 1691 root 2 59 0 27M 680K sleep 4:22 0.00% webservd 24386 root 1 59 0 15M 11M sleep 2:50 0.00% perl 23259 root 1 59 0 11M 4240K sleep 2:42 0.00% perl 24718 root 1 59 0 11M 5464K sleep 2:29 0.00% perl 22810 root 1 59 0 19M 11M sleep 2:21 0.00% perl 24451 root 1 53 2 11M 3800K sleep 2:18 0.00% perl 18501 root 1 56 1 11M 3960K sleep 2:18 0.00% perl 14450 root 1 56 1 15M 6920K sleep 1:49 0.00% perl Server 2 42 processes: 40 sleeping, 1 zombie, 1 on cpu CPU states: 98.8% idle, 0.4% user, 0.8% kernel, 0.0% iowait, 0.0% swap Memory: 1024M real, 31M free, 554M swap in use, 3696M swap free PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND 5607 webservd 74 29 10 284M 173M sleep 20:14 0.21% webservd 15919 support 1 59 0 4056K 2520K cpu/1 0:08 0.09% top 13138 root 10 59 0 34M 1952K sleep 210:51 0.08% java 13753 root 1 59 0 22M 12M sleep 170:15 0.07% perl 22979 root 33 29 10 112M 7864K sleep 85:07 0.04% webservd 22930 root 1 59 0 3424K 1552K sleep 17:47 0.01% xntpd 22978 root 2 59 0 27M 2296K sleep 10:49 0.00% webservd 13571 root 1 59 0 9400K 5112K sleep 5:52 0.00% perl 5606 root 2 29 10 29M 9056K sleep 0:36 0.00% webservd 15910 support 1 59 0 9128K 2616K sleep 0:00 0.00% sshd 13106 root 1 59 0 82M 3520K sleep 7:47 0.00% perl 13547 root 1 59 0 12M 5528K sleep 6:38 0.00% perl 13518 root 1 59 0 9336K 3792K sleep 6:24 0.00% perl 13399 root 1 56 1 8072K 3616K sleep 5:18 0.00% perl 13557 root 1 53 2 8248K 3624K sleep 5:12 0.00% perl

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• performance comparision between Zend Lucene and Java Lucene

  - by Carson

  Zend Lucene and Java Lucene are built in PHP and java repectively, and PHP language has a higher level than java. Just wondering How big the performance difference among these two, regarding to index building and data searching? Is it much more effective to let java create and rebuild index, and let php use the index?

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• How to send audio data from Java Applet to Rails controller

  - by cooldude

  Hi, I have to send the audio data in byte array obtain by recording from java applet at the client side to rails server at the controller in order to save. So, what encoding parameters at the applet side be used and in what form the audio data be converted like String or byte array so that rails correctly recieve data and then I can save that data at the rails in the file. As currently the audio file made by rails controller is not playing. It is the following ERROR : LAVF_header: av_open_input_stream() failed while playing with the mplayer. Here is the Java Code: package networksocket; import java.util.logging.Level; import java.util.logging.Logger; import javax.swing.JApplet; import java.net.*; import java.io.*; import java.awt.event.*; import java.awt.*; import java.sql.*; import javax.swing.*; import javax.swing.border.*; import java.awt.*; import java.util.Properties; import javax.swing.plaf.basic.BasicSplitPaneUI.BasicHorizontalLayoutManager; import sun.awt.HorizBagLayout; import sun.awt.VerticalBagLayout; import sun.misc.BASE64Encoder; /** * * @author mukand */ public class Urlconnection extends JApplet implements ActionListener { /** * Initialization method that will be called after the applet is loaded * into the browser. */ public BufferedInputStream in; public BufferedOutputStream out; public String line; public FileOutputStream file; public int bytesread; public int toread=1024; byte b[]= new byte[toread]; public String f="FINISH"; public String match; public File fileopen; public JTextArea jTextArea; public Button refreshButton; public HttpURLConnection urlConn; public URL url; OutputStreamWriter wr; BufferedReader rd; @Override public void init() { // TODO start asynchronous download of heavy resources //textField= new TextField("START"); //getContentPane().add(textField); JPanel p = new JPanel(); jTextArea= new JTextArea(1500,1500); p.setLayout(new GridLayout(1,1, 1,1)); p.add(new JLabel("Server Details")); p.add(jTextArea); Container content = getContentPane(); content.setLayout(new GridBagLayout()); // Used to center the panel content.add(p); jTextArea.setLineWrap(true); refreshButton = new java.awt.Button("Refresh"); refreshButton.reshape(287,49,71,23); refreshButton.setFont(new Font("Dialog", Font.PLAIN, 12)); refreshButton.addActionListener(this); add(refreshButton); Properties properties = System.getProperties(); properties.put("http.proxyHost", "netmon.iitb.ac.in"); properties.put("http.proxyPort", "80"); } @Override public void actionPerformed(ActionEvent e) { try { url = new URL("http://localhost:3000/audio/audiorecieve"); urlConn = (HttpURLConnection)url.openConnection(); //String login = "mukandagarwal:rammstein$"; //String encodedLogin = new BASE64Encoder().encodeBuffer(login.getBytes()); //urlConn.setRequestProperty("Proxy-Authorization",login); urlConn.setRequestMethod("POST"); // urlConn.setRequestProperty("Content-Type", //"application/octet-stream"); //urlConn.setRequestProperty("Content-Type","audio/mpeg");//"application/x-www- form-urlencoded"); //urlConn.setRequestProperty("Content-Type","application/x-www- form-urlencoded"); //urlConn.setRequestProperty("Content-Length", "" + // Integer.toString(urlParameters.getBytes().length)); urlConn.setRequestProperty("Content-Language", "UTF-8"); urlConn.setDoOutput(true); urlConn.setDoInput(true); byte bread[]=new byte[2048]; int iread; char c; String data=URLEncoder.encode("key1", "UTF-8")+ "="; //String data="key1="; FileInputStream fileread= new FileInputStream("//home//mukand//Hellion.ogg");//Dogs.mp3");//Desktop//mausam1.mp3"); while((iread=fileread.read(bread))!=-1) { //data+=(new String()); /*for(int i=0;i<iread;i++) { //c=(char)bread[i]; System.out.println(bread[i]); }*/ data+= URLEncoder.encode(new String(bread,iread), "UTF-8");//new String(new String(bread));// // data+=new String(bread,iread); } //urlConn.setRequestProperty("Content-Length",Integer.toString(data.getBytes().length)); System.out.println(data); //data+=URLEncoder.encode("mukand", "UTF-8"); //data += "&" + URLEncoder.encode("key2", "UTF-8") + "=" + URLEncoder.encode("value2", "UTF-8"); //data="key1="; wr = new OutputStreamWriter(urlConn.getOutputStream());//urlConn.getOutputStream(); //if((iread=fileread.read(bread))!=-1) // wr.write(bread,0,iread); wr.write(data); wr.flush(); fileread.close(); jTextArea.append("Send"); // Get the response rd = new BufferedReader(new InputStreamReader(urlConn.getInputStream())); while ((line = rd.readLine()) != null) { jTextArea.append(line); } wr.close(); rd.close(); //jTextArea.append("click"); } catch (MalformedURLException ex) { Logger.getLogger(Urlconnection.class.getName()).log(Level.SEVERE, null, ex); } catch (IOException ex) { Logger.getLogger(Urlconnection.class.getName()).log(Level.SEVERE, null, ex); } } @Override public void start() { } @Override public void stop() { } @Override public void destroy() { } // TODO overwrite start(), stop() and destroy() methods } Here is the Rails controller function for recieving: def audiorecieve puts "///////////////////////////////////////******RECIEVED*******////" puts params[:key1]#+" "+params[:key2] data=params[:key1] #request.env('RAW_POST_DATA') file=File.new("audiodata.ogg", 'w') file.write(data) file.flush file.close puts "////**************DONE***********//////////////////////" end Please reply quickly

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• Java heap space

  - by Gandalf StormCrow

  I get this message during build of my project java.lang.OutOfMemoryError: Java heap space How do I increase heap space, I've got 8Gb or RAM its impossible that maven consumed that much, I found this http://vikashazrati.wordpress.com/2007/07/26/quicktip-how-to-increase-the-java-heap-memory-for-maven-2-on-linux/ how to do it on linux, but I'm on windows 7. How can I change java heap space under windows ?

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• Please help me with java ee and eclipse tutorial

  - by tmt055

  im new to java ee platform and im having a hard time searching for a book for java ee that uses eclipse IDE. So please can you tell me any book that involves java ee and eclipse for beginners. and some tips from you how to learn this stuff and a follow up question, is java EE still good 20 years from now?

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• How to create "java project" in eclipse using java program not manually??

  - by Rahul

  Hi, I want to create a java project in eclipe using ..java program(java code)..when i run my java programme at that time it should create project in workspace..project name should be hardcoded..eq "AutoprojectCreate"..Can anyone helpme thanks in advance..

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• Permissions problem running Apache ActiveMQ

  - by Edd

  I'm wanting to use Apache ActiveMQ on Ubuntu 12.04 LTS, but am running into what looks like a permissions problem when I try to run it as follows: edd:~$ sudo activemq --version INFO: Loading '/usr/share/activemq/activemq-options' INFO: Using java '/usr/lib/jvm/java-6-openjdk//bin/java' INFO: changing to user 'activemq' to invoke java Java Runtime: Sun Microsystems Inc. 1.6.0_24 /usr/lib/jvm/java-6-openjdk-amd64/jre Heap sizes: current=502464k free=499842k max=502464k JVM args: -Xms512M -Xmx512M -Dorg.apache.activemq.UseDedicatedTaskRunner=true -Dactivemq.classpath=/var/lib/activemq//conf;; -Dactivemq.home=/usr/share/activemq -Dactivemq.base=/var/lib/activemq/ ACTIVEMQ_HOME: /usr/share/activemq ACTIVEMQ_BASE: /var/lib/activemq ActiveMQ 5.5.0 For help or more information please see: http://activemq.apache.org edd:~$ sudo activemq start INFO: Loading '/usr/share/activemq/activemq-options' INFO: Using java '/usr/lib/jvm/java-6-openjdk//bin/java' INFO: Starting - inspect logfiles specified in logging.properties and log4j.properties to get details INFO: changing to user 'activemq' to invoke java -su: line 2: /var/run/activemq.pid: Permission denied INFO: pidfile created : '/var/run/activemq.pid' (pid '7811') edd:~$ sudo activemq status INFO: Loading '/usr/share/activemq/activemq-options' INFO: Using java '/usr/lib/jvm/java-6-openjdk//bin/java' ActiveMQ not running edd:~$ ps ax | grep 'activemq' 8040 pts/0 S+ 0:00 grep --color=auto activemq I installed ActiveMQ using sudo apt-get install activemq. Apologies if there's any additional information missing - I'm fairly new to Linux as you may well have guessed!

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• Dr. Robert Ballard: Special Guest at Java Strategy Keynote Sunday

  - by Tori Wieldt

  Dr. Robert Ballard, famed explorer who found the Titanic at its final resting place, will be at the Java Strategy Keynote on Sunday. Among the most accomplished and well known of the world's deep-sea explorers, Dr. Ballard is best known for his historic discoveries of hydrothermal vents, the sunken R.M.S. Titanic, the German battleship Bismarck, and numerous other contemporary and ancient shipwrecks around the world. During his long career he has conducted more than 120 deep-sea expeditions using the latest in exploration technology, and he is a pioneer in the early use of deep-diving submarines. You can learn more about Dr. Ballard and undersea exploration at National Geographic and TED. The first 1,000 people to arrive at the JavaOne Keynote hall on Sunday will receive a copy of Dr. Ballard's TV show "The Alien Deep" on Blu-Ray. The Alien Deep explores the sea, thousands of feet beneath the surface, far from the first crack of light, where the planet’s last and greatest secrets hide in the cold darkness of endless night. Viewers get to see underwater worlds via submersible where no one has gone before. The JavaOne Strategy Keynote is on Sunday at 4:00pm PT at Masonic Auditorium, 1111 California Street. See you there!

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• Pivotal Announces JSR-352 Compliance for Spring Batch

  - by reza_rahman

  Pivotal, the company currently funding development of the popular Spring Framework, recently announced JSR 352 (aka Batch Applications for the Java Platform) compliance for the Spring Batch project. More specifically, Spring Batch targets JSR-352 Java SE runtime compatibility rather than Java EE runtime compatibility. If you are surprised that APIs included in Java EE can pass TCKs targeted for Java SE, you should not be. Many other Java EE APIs target compatibility in Java SE environments such as JMS and JPA. You can read about Spring Batch's support for JSR-352 here as well as the Spring configuration to get JSR-352 working in Spring (typically a very low level implementation concern intended to be completely transparent to most JSR-352 users). JSR 352 is one of the few very encouraging cases of major active contribution to the Java EE standard from the Spring development team (the other major effort being Rod Johnson's co-leadership of JSR 330 along with Bob Lee). While IBM's Christopher Vignola led the spec and contributed IBM's years of highly mission critical batch processing experience from products like WebSphere Compute Grid and z/OS batch, the Spring team provided major influences to the API in particular for the chunk processing, listeners, splits and operational interfaces. The GlassFish team's own Mahesh Kannan also contributed, in particular by implementing much of the Java EE integration work for the reference implementation. This was an excellent example of multilateral engineering collaboration through the standards process. For many complex reasons it is not too hard to find evidence of less than amicable interaction between the Spring ecosystem and the Java EE standard over the years if one cares to dig deep enough. In reality most developers see Spring and Java EE as two sides of the same server-side Java coin. At the core Spring and Java EE ecosystems have always shared deep undercurrents of common user bases, bi-directional flows of ideas and perhaps genuine if not begrudging mutual respect. We can all hope for continued strength for both ecosystems and graceful high notes of collaboration via efforts like JSR 352.

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• Scheduling of jobs in the presence of constraints in Java

  - by Asgard

  I want to know how to implement a solution to this problem: A task is performed by running, by more people, some basic jobs with known duration in time units (days, months, etc..). The execution of the jobs could lead to the existence of time constraints: a job, for example, can not start if it is not over another (or others) and so on. I want to design and build an application to check the correctness of jobs activities and to propose a schedule of jobs, if any, which is respectful of the constraints. Input must provide the jobs and associated constraints. The expected output is the scheduling of jobs. The specification of an elementary job consists of the pair <jobs-id, duration> A constraint is expressed by means of a quintuple of the type <S/E, id-job1, B/A, S/E, id-job2> the beginning (S) or the end (E) of a jobs Id-job1, must take place before (B) / after (A) of the beginning (S) / end (E) of the Id-job2. If there are no dependencies between some jobs, then jobs can be done before, in parallel. As a simple example, consider the input: jobs jobs(0, 3) jobs(1, 4) jobs(2, 5) jobs(3, 3) jobs(4, 3) constraints constraints(S, 1, A, E, 0) constraints(S, 4, A, E, 2) Possible output: t 0 1 2 3 4 0 * - * * - 1 * - * * - 2 * - * * - 3 * - * * - 4 - * * - - 5 - * * - - 6 - * - - * 7 - * - - * 8 - * - - * 9 - - - - * How to code an efficient java scheduler(avoiding the intense backtracking if is possible) to manage the jobs with these constraints, as described??? I have seen a discussion on a thread in a forum where an user seems has solved the problem easily, but He haven't given enough details to the users to compile a working project(I'm noob), and I'm interested to know an effective implementation of the solution (without using external libraries). If someone help me, I'll give to him a very good feedback ;)

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• Java - System design with distributed Queues and Locks

  - by sunny

  Looking for inputs to evaluate a design for a system (java) which would have a distributed queue serving several (but not too many) nodes. These nodes would process objects present in the distributed queue and on occasion require a distributed lock across the cluster on an arbitrary (distributed) data structures. These (distributed) data structures could potentially lie in a distributed cache. Eliminating Terracotta (DSO),Hazelcast and Akka what could be alternative choices. Currently considering zookeeper as a distributed locking mechanism. Since the recommendation of a znode is not to exceed the 1M size , the understanding is that zookeeper should not be used a distributed queue. And also from Netflix curator tech note 4. So should a distributed cache, say like memcached, or redis be used to emulate a distributed queue ? i.e. The distributed queue will be stored in the caches and will be locked cluster-wide via zookeeper. Are there potential pitfalls with this high-level approach. The objects don't need to be taken off the queue. The object will pass through a lifecycle which will determine its removal from the queue. There would be about 10k+ objects in a queue at a given time changing states and any node could service one stage of the object's lifecycle. (Although not strictly necessary .. i.e. one node could serve the entire lifecycle if that is more efficient.) Any suggestions/alternatives ? sidenote: new to zookeeper ; redis etc.

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• Talking JavaOne with Rock Star Raghavan Srinivas

  - by Janice J. Heiss

  Raghavan Srinivas, affectionately known as “Rags,” is a two-time JavaOne Rock Star (from 2005 and 2011) who, as a Developer Advocate at Couchbase, gets his hands dirty with emerging technology directions and trends. His general focus is on distributed systems, with a specialization in cloud computing. He worked on Hadoop and HBase during its early stages, has spoken at conferences world-wide on a variety of technical topics, conducted and organized Hands-on Labs and taught graduate classes.He has 20 years of hands-on software development and over 10 years of architecture and technology evangelism experience and has worked for Digital Equipment Corporation, Sun Microsystems, Intuit and Accenture. He has evangelized and influenced the architecture of numerous technologies including the early releases of JavaFX, Java, Java EE, Java and XML, Java ME, AJAX and Web 2.0, and Java Security.Rags will be giving these sessions at JavaOne 2012: CON3570 -- Autosharding Enterprise to Social Gaming Applications with NoSQL and Couchbase CON3257 -- Script Bowl 2012: The Battle of the JVM-Based Languages (with Guillaume Laforge, Aaron Bedra, Dick Wall, and Dr Nic Williams) Rags emphasized the importance of the Cloud: “The Cloud and the Big Data are popular technologies not merely because they are trendy, but, largely due to the fact that it's possible to do massive data mining and use that information for business advantage,” he explained. I asked him what we should know about Hadoop. “Hadoop,” he remarked, “is mainly about using commodity hardware and achieving unprecedented scalability. At the heart of all this is the Java Virtual Machine which is running on each of these nodes. The vision of taking the processing to where the data resides is made possible by Java and Hadoop.” And the most exciting thing happening in the world of Java today? “I read recently that Java projects on github.com are just off the charts when compared to other projects. It's exciting to realize the robust growth of Java and the degree of collaboration amongst Java programmers.” He encourages Java developers to take advantage of Java 7 for Mac OS X which is now available for download. At the same time, he also encourages us to read the caveats. Originally published on blogs.oracle.com/javaone.

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• Talking JavaOne with Rock Star Raghavan Srinivas

  - by Janice J. Heiss

  Raghavan Srinivas, affectionately known as “Rags,” is a two-time JavaOne Rock Star (from 2005 and 2011) who, as a Developer Advocate at Couchbase, gets his hands dirty with emerging technology directions and trends. His general focus is on distributed systems, with a specialization in cloud computing. He worked on Hadoop and HBase during its early stages, has spoken at conferences world-wide on a variety of technical topics, conducted and organized Hands-on Labs and taught graduate classes.He has 20 years of hands-on software development and over 10 years of architecture and technology evangelism experience and has worked for Digital Equipment Corporation, Sun Microsystems, Intuit and Accenture. He has evangelized and influenced the architecture of numerous technologies including the early releases of JavaFX, Java, Java EE, Java and XML, Java ME, AJAX and Web 2.0, and Java Security.Rags will be giving these sessions at JavaOne 2012: CON3570 -- Autosharding Enterprise to Social Gaming Applications with NoSQL and Couchbase CON3257 -- Script Bowl 2012: The Battle of the JVM-Based Languages (with Guillaume Laforge, Aaron Bedra, Dick Wall, and Dr Nic Williams) Rags emphasized the importance of the Cloud: “The Cloud and the Big Data are popular technologies not merely because they are trendy, but, largely due to the fact that it's possible to do massive data mining and use that information for business advantage,” he explained. I asked him what we should know about Hadoop. “Hadoop,” he remarked, “is mainly about using commodity hardware and achieving unprecedented scalability. At the heart of all this is the Java Virtual Machine which is running on each of these nodes. The vision of taking the processing to where the data resides is made possible by Java and Hadoop.” And the most exciting thing happening in the world of Java today? “I read recently that Java projects on github.com are just off the charts when compared to other projects. It's exciting to realize the robust growth of Java and the degree of collaboration amongst Java programmers.” He encourages Java developers to take advantage of Java 7 for Mac OS X which is now available for download. At the same time, he also encourages us to read the caveats.

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• Eclipse on mac: how comes that everytime I install an Eclipse plug-in on my mac I always get this er

  - by Patrick

  I'm using Eclipse for several projects on Leopard OSX. I've installed several versions (Classic, PDT, etc). When I install a new plug-in using the Help Install New Software functionality and I restart it, I always get the same error and I cannot anymore use it: !ENTRY org.eclipse.equinox.launcher 4 0 2010-04-20 17:32:42.540 !MESSAGE Exception launching the Eclipse Platform: !STACK java.lang.ClassNotFoundException: org.eclipse.core.runtime.adaptor.EclipseStarter at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:317) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:556) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514) at org.eclipse.equinox.launcher.Main.run(Main.java:1311) What is causing the error? How can I get these plugins to work? Thanks

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• Java web app, with plugin framework and ability to connect to source for updates

  - by lessthancommon

  I've searched all around for some good sources, but either have been searching for the wrong keywords, or I'm just missing something. I'm looking to redevelop a web app I've been using for some time now. Many parts are out of date, and we're constantly throwing in little hacks to attempt to give it new life. So what I'd like to do is re-engineer it from the ground up, built on some sort of plug-in framework. Before I continue, I'm more or less an intermediate Java programmer. In some ways, I'm hoping to use this project as a big learning experience. I've read a lot about OSGi, and it seems that's the most complete framework. Ideally, I would like an end result web app which I can run one instance as my hosting environment, and other instances can connect to it to grab new and updated plug-ins. Eventually I'll want to lock down these plug-ins based on some undecided criteria of who can get them (basically some will simply be updates, others will provide new functionality and should be "purchased" through an external system). But that will probably be handled in a later phase. There should be an administration view for managing bundles in a hot environment (looking to avoid having to restart the server for an update). I know all these things are possible, I'm just trying to find some good resources for reference. All the OSGi tutorials I'm finding seem to be too simplistic. If anyone here can guide me in the right direction on any or all of the items I'm looking for, it would be much appreciated. Also, this is my first post, so I'll take any comments/criticisms about the content of my post. Thanks!

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• Two equal items in alternatives list

  - by Red Planet

  I want to have two JDKs. The first one was installed a long time ago to /usr/lib/jvm/java-7-oracle/. I installed the second version and executed following commands to add it to alternatives: red-planet@laptop:~$ sudo update-alternatives --install "/usr/bin/java" "java" "/opt/java_1.6.0_35/bin/java" 2 update-alternatives: using /opt/java_1.6.0_35/bin/java to provide /usr/bin/java (java) in auto mode. red-planet@laptop:~$ sudo update-alternatives --install "/usr/bin/javac" "javac" "/opt/java_1.6.0_35/bin/javac" 2 update-alternatives: using /opt/java_1.6.0_35/bin/javac to provide /usr/bin/javac (javac) in auto mode. red-planet@laptop:~$ sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/opt/java_1.6.0_35/bin/javaws" 2 update-alternatives: using /opt/java_1.6.0_35/bin/javaws to provide /usr/bin/javaws (javaws) in auto mode. And configured: There are 2 choices for the alternative java (providing /usr/bin/java). Selection Path Priority Status ------------------------------------------------------------ * 0 /opt/java_1.6.0_35/bin/java 2 auto mode 1 /opt/java_1.6.0_35/bin/java 2 manual mode 2 /usr/lib/jvm/java-7-oracle/bin/java 1 manual mode Press enter to keep the current choice[*], or type selection number: Why do I have two equal items in the list?

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• Eclipse Java Code Formatter in NetBeans Plugin Manager

  - by Geertjan

  Great news for Eclipse refugees everywhere. Benno Markiewicz forked the Eclipse formatter plugin that I blogged about sometime ago (here and here)... and he fixed many bugs, while also adding new features. It's a handy plugin when you're (a) switching from Eclipse to NetBeans and want to continue using your old formatting rules and (b) working in a polyglot IDE team, i.e., now the formatting rules defined in Eclipse can be imported into NetBeans IDE and everyone will happily be able to conform to the same set of formatting standards. And now you can get it directly from Tools | Plugins in NetBeans IDE 7.4: News from Benno on the plugin, received from him today: The plugin is verified by the NetBeans community and available in the Plugin Manager in NetBeans IDE 7.4 (as shown above) and also at the NetBeans Plugin Portal here, where you can also read quite some info about the plugin:  http://plugins.netbeans.org/plugin/50877/eclipse-code-formatter-for-java The issue with empty undo buffer was solved with the help of junichi11: https://github.com/markiewb/eclipsecodeformatter_for_netbeans/issues/18 The issue with the lost breakpoints remains unsolved and there was no further feedback. That is the main reason why the save action isn't activated by default. See also the open known issues at https://github.com/markiewb/eclipsecodeformatter_for_netbeans/issues?state=open Features are as follows:  Global configuration and project specific configuration.  On save action, which is disabled by default. Show the used formatter as a notification, which is enabled by default.  Finally, Benno testifies to the usefulness, stability, and reliability of the plugin: I use the Eclipse formatter provided by this plugin every day at work. Before I commit, I format the sources. It works and that's it. I am pleased with it. Here's where the Eclipse formatter is defined globally in Tools | Options: And here is per-project configuration, i.e., use the Project Properties dialog of any project to override the global settings:  Interested to hear from anyone who tries the plugin and has any feedback of any kind! 

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• JCP 2012 Award Nominations are now open!

  - by heathervc

  The 10th JCP Annual Awards Nominations are now open until 16 July 2012. Submit nominations to [email protected] or use form here. The Java Community Process (JCP) program celebrates success. Members of the community nominate worthy participants, Spec Leads, and Java Specification Requests (JSRs) in order to cheer on the hard work and creativity that produces ground-breaking results for the community and industry in the Java Standard Edition (SE), Java Enterprise Edition (EE), or Java Micro Edition (ME) platforms. The community gets together every year at the JavaOne conference to applaud in person the winners of three awards: JCP Member/Participant of the Year, Outstanding Spec Lead, and Most Significant JSR. This year’s unveiling will occur Tuesday evening, 2 October, at the Annual JCP Community Party held in San Francisco.  Nominate today...descriptions of the award categories for this year: JCP Member/Participant Of The Year - This award recognizes the corporate or individual member (either Member or Participant) who has made the most significant positive impact on the community in the past year. Leadership, investment in the community, and innovation are some of the qualities that EC Members look for in voting for this award. Outstanding Spec Lead - The role of Spec Lead is not an easy one, and the person who takes that responsibility must be, among other things, technically savvy, able to build consensus in spite of diverse corporate goals, and focused on efficiency and execution. This award recognizes the person who has brought together these qualities the best in the past year, in leading a JSR for the Java community (Java SE, Java EE or Java ME). Most Significant JSR - Specification development is key to the success of the JCP program and helps ensure we remain a fresh and vibrant community. This award recognizes the Spec Lead and Expert Group that have contributed (either in progress or final) the most significant JSR for the Java community (Java SE, Java EE or Java ME) in the past year.

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• Project Jigsaw: On the next train

  - by Mark Reinhold

  I recently proposed to defer Project Jigsaw from Java 8 to Java 9. Feedback on the proposal was about evenly divided as to whether Java 8 should be delayed for Jigsaw, Jigsaw should be deferred to Java 9, or some other, usually less-realistic, option should be taken. The ultimate decision rested, of course, with the Java SE 8 (JSR 337) Expert Group. After due consideration, a strong majority of the EG agreed to my proposal. In light of this decision we can still make progress in Java 8 toward the convergence of the higher-end Java ME Platforms with Java SE. I previously suggested that we consider defining a small number of Profiles which would allow compact configurations of the SE Platform to be built and deployed. JEP 161 lays out a specific initial proposal for such Profiles. There is also much useful work to be done in Java 8 toward the fully-modular platform in Java 9. Alan Bateman has submitted JEP 162, which proposes some changes in Java 8 to smooth the eventual transition to modules, to provide new tools to help developers prepare for modularity, and to deprecate and then, in Java 9, actually remove certain API elements that are a significant impediment to modularization. Thanks to everyone who responded to the proposal with comments and questions. As I wrote initially, deferring Jigsaw to a Java 9 release in 2015 is by no means a pleasant decision. It does, however, still appear to be the best available option, and it is now the plan of record.

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• How would one build a relational database on a key-value store, a-la Berkeley DB's SQL interface?

  - by coleifer

  I've been checking out Berkeley DB and was impressed to find that it supported a SQL interface that is "nearly identical" to SQLite. http://docs.oracle.com/cd/E17076_02/html/bdb-sql/dbsqlbasics.html#identicalusage I'm very curious, at a high-level, how this kind of interface might have been architected. For instance: since values are "transparent", how do you efficiently query and sort by value how are limits and offsets performed efficiently on large result sets how would the keys be structured and serialized for good average-case performance

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• Advanced Experiments with JavaScript, CSS, HTML, JavaFX, and Java

  - by Geertjan

  Once you're embedding JavaScript, CSS, and HTML into your Java desktop application, via the JavaFX browser, a whole range of new possibilities open up to you. For example, here's an impressive page on-line, notice that you can drag items and drop them in new places: http://nettuts.s3.amazonaws.com/127_iNETTUTS/demo/index.html The source code of the above is provided too, so you can drop the various files directly into your NetBeans module and use the JavaFX WebEngine to load the HTML page into the JavaFX browser. Once the JavaFX browser is in a NetBeans TopComponent, you'll have the start of an off-line news composer, something like this: WebView view = new WebView(); view.setMinSize(widthDouble, heightDouble); view.setPrefSize(widthDouble, heightDouble); webengine = view.getEngine(); URL url = getClass().getResource("index.html"); webengine.load(url.toExternalForm()); webengine.getLoadWorker().stateProperty().addListener( new ChangeListener() { @Override public void changed(ObservableValue ov, State oldState, State newState) { if (newState == State.SUCCEEDED) { Document document = (Document) webengine.executeScript("document"); NodeList list = document.getElementById("columns").getChildNodes(); for (int i = 0; i < list.getLength(); i++) { EventTarget et = (EventTarget) list.item(i); et.addEventListener("click", new EventListener() { @Override public void handleEvent(Event evt) { instanceContent.add(new Date()); } }, true); } } } }); The above is the code showing how, whenever a news item is clicked, the current date can be published into the Lookup. As you can see, I have a viewer component listening to the Lookup for dates.

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• At the Java DEMOgrounds - ZeroTurnaround and its LiveRebel 2.5

  - by Janice J. Heiss

  At the ZeroTurnaround demo, I spoke with Krishnan Badrinarayanan, their Product Marketing Manager. ZeroTurnaround, the creator of JRebel and LiveRebel, describes itself on their site as a company “dedicated to changing the way the world develops, tests and runs Java applications."“We just launched LiveRebel 2.5 today,” stated Badrinarayanan, “which enables companies to embrace the concept and practice of continuous delivery, which means having a pipeline that takes products right from the developers to an end-user, faster, more frequently -- all the while ensuring that it’s a quality product that does not break in production. So customers don’t feel the discontinuity that something has changed under them and that they can’t deal with the change. And all this happens while there is zero down time.”He pointed out that Salesforce.com is not useable from 3 a.m. to 5 a.m. on Saturday because they are engaged in maintenance. “With LiveRebel 2.5, you can unify the whole delivery chain without having any downtime at all,” he said. “There are many products that tell customers to take their tools and change how they work as an organization so that you they have to conform to the way the tool prescribes them to work as an application team. We take a more pragmatic approach. A lot of companies might use Jenkins or Bamboo to do continuous integration. We extend that. We say, take our product, take LiveRebel okay, and integrate it with Jenkins – you can do that quickly, so that, in half a day, you will be up and running. And let LiveRebel automate your deployment processes and all the automated tasks that go with it. Right from tests to the staging environment to production -- all with zero downtime and with no impact on users currently using the system.” “So if you were to make the update right now and you had 100 users on your system, they would not even know this was happening. It would maintain their sessions and transfer them over to the new version, all in the background.”

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• GlassFish/Java EE Community Open Forum Tomorrow!

  - by reza_rahman

  Still have lingering questions on the goals and future of GlassFish? Want to know a little more about the upcoming GlassFish 4.0.1 release? Something on your mind about Java EE 8/GlassFish 5? You have a golden opportunity to pose your questions and speak your mind tomorrow! The good folks over at C2B2 have gone through a lot of time and effort to organize a very useful online event for the London GlassFish User Group - they are having me answer all your questions online, in real time, "face-to-face". Steve Millidge of C2B2 will be moderating the questions and joining the conversation. Did I mention the event was online, free and open to anyone? The event is tomorrow (May 30th), so make sure to register as soon as possible through the C2B2 website (the registration page has more details on the event). It will be held at 4:30 PM BST / 11:30 AM EST / 8:30 AM PST - you must register to participate. Hope to talk to you tomorrow?

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• What is the fastest cyclic synchronization in Java (ExecutorService vs. CyclicBarrier vs. X)?

  - by Alex Dunlop

  Which Java synchronization construct is likely to provide the best performance for a concurrent, iterative processing scenario with a fixed number of threads like the one outlined below? After experimenting on my own for a while (using ExecutorService and CyclicBarrier) and being somewhat surprised by the results, I would be grateful for some expert advice and maybe some new ideas. Existing questions here do not seem to focus primarily on performance, hence this new one. Thanks in advance! The core of the app is a simple iterative data processing algorithm, parallelized to the spread the computational load across 8 cores on a Mac Pro, running OS X 10.6 and Java 1.6.0_07. The data to be processed is split into 8 blocks and each block is fed to a Runnable to be executed by one of a fixed number of threads. Parallelizing the algorithm was fairly straightforward, and it functionally works as desired, but its performance is not yet what I think it could be. The app seems to spend a lot of time in system calls synchronizing, so after some profiling I wonder whether I selected the most appropriate synchronization mechanism(s). A key requirement of the algorithm is that it needs to proceed in stages, so the threads need to sync up at the end of each stage. The main thread prepares the work (very low overhead), passes it to the threads, lets them work on it, then proceeds when all threads are done, rearranges the work (again very low overhead) and repeats the cycle. The machine is dedicated to this task, Garbage Collection is minimized by using per-thread pools of pre-allocated items, and the number of threads can be fixed (no incoming requests or the like, just one thread per CPU core). V1 - ExecutorService My first implementation used an ExecutorService with 8 worker threads. The program creates 8 tasks holding the work and then lets them work on it, roughly like this: // create one thread per CPU executorService = Executors.newFixedThreadPool( 8 ); ... // now process data in cycles while( ...) { // package data into 8 work items ... // create one Callable task per work item ... // submit the Callables to the worker threads executorService.invokeAll( taskList ); } This works well functionally (it does what it should), and for very large work items indeed all 8 CPUs become highly loaded, as much as the processing algorithm would be expected to allow (some work items will finish faster than others, then idle). However, as the work items become smaller (and this is not really under the program's control), the user CPU load shrinks dramatically: blocksize | system | user | cycles/sec 256k 1.8% 85% 1.30 64k 2.5% 77% 5.6 16k 4% 64% 22.5 4096 8% 56% 86 1024 13% 38% 227 256 17% 19% 420 64 19% 17% 948 16 19% 13% 1626 Legend: - block size = size of the work item (= computational steps) - system = system load, as shown in OS X Activity Monitor (red bar) - user = user load, as shown in OS X Activity Monitor (green bar) - cycles/sec = iterations through the main while loop, more is better The primary area of concern here is the high percentage of time spent in the system, which appears to be driven by thread synchronization calls. As expected, for smaller work items, ExecutorService.invokeAll() will require relatively more effort to sync up the threads versus the amount of work being performed in each thread. But since ExecutorService is more generic than it would need to be for this use case (it can queue tasks for threads if there are more tasks than cores), I though maybe there would be a leaner synchronization construct. V2 - CyclicBarrier The next implementation used a CyclicBarrier to sync up the threads before receiving work and after completing it, roughly as follows: main() { // create the barrier barrier = new CyclicBarrier( 8 + 1 ); // create Runable for thread, tell it about the barrier Runnable task = new WorkerThreadRunnable( barrier ); // start the threads for( int i = 0; i < 8; i++ ) { // create one thread per core new Thread( task ).start(); } while( ... ) { // tell threads about the work ... // N threads + this will call await(), then system proceeds barrier.await(); // ... now worker threads work on the work... // wait for worker threads to finish barrier.await(); } } class WorkerThreadRunnable implements Runnable { CyclicBarrier barrier; WorkerThreadRunnable( CyclicBarrier barrier ) { this.barrier = barrier; } public void run() { while( true ) { // wait for work barrier.await(); // do the work ... // wait for everyone else to finish barrier.await(); } } } Again, this works well functionally (it does what it should), and for very large work items indeed all 8 CPUs become highly loaded, as before. However, as the work items become smaller, the load still shrinks dramatically: blocksize | system | user | cycles/sec 256k 1.9% 85% 1.30 64k 2.7% 78% 6.1 16k 5.5% 52% 25 4096 9% 29% 64 1024 11% 15% 117 256 12% 8% 169 64 12% 6.5% 285 16 12% 6% 377 For large work items, synchronization is negligible and the performance is identical to V1. But unexpectedly, the results of the (highly specialized) CyclicBarrier seem MUCH WORSE than those for the (generic) ExecutorService: throughput (cycles/sec) is only about 1/4th of V1. A preliminary conclusion would be that even though this seems to be the advertised ideal use case for CyclicBarrier, it performs much worse than the generic ExecutorService. V3 - Wait/Notify + CyclicBarrier It seemed worth a try to replace the first cyclic barrier await() with a simple wait/notify mechanism: main() { // create the barrier // create Runable for thread, tell it about the barrier // start the threads while( ... ) { // tell threads about the work // for each: workerThreadRunnable.setWorkItem( ... ); // ... now worker threads work on the work... // wait for worker threads to finish barrier.await(); } } class WorkerThreadRunnable implements Runnable { CyclicBarrier barrier; @NotNull volatile private Callable<Integer> workItem; WorkerThreadRunnable( CyclicBarrier barrier ) { this.barrier = barrier; this.workItem = NO_WORK; } final protected void setWorkItem( @NotNull final Callable<Integer> callable ) { synchronized( this ) { workItem = callable; notify(); } } public void run() { while( true ) { // wait for work while( true ) { synchronized( this ) { if( workItem != NO_WORK ) break; try { wait(); } catch( InterruptedException e ) { e.printStackTrace(); } } } // do the work ... // wait for everyone else to finish barrier.await(); } } } Again, this works well functionally (it does what it should). blocksize | system | user | cycles/sec 256k 1.9% 85% 1.30 64k 2.4% 80% 6.3 16k 4.6% 60% 30.1 4096 8.6% 41% 98.5 1024 12% 23% 202 256 14% 11.6% 299 64 14% 10.0% 518 16 14.8% 8.7% 679 The throughput for small work items is still much worse than that of the ExecutorService, but about 2x that of the CyclicBarrier. Eliminating one CyclicBarrier eliminates half of the gap. V4 - Busy wait instead of wait/notify Since this app is the primary one running on the system and the cores idle anyway if they're not busy with a work item, why not try a busy wait for work items in each thread, even if that spins the CPU needlessly. The worker thread code changes as follows: class WorkerThreadRunnable implements Runnable { // as before final protected void setWorkItem( @NotNull final Callable<Integer> callable ) { workItem = callable; } public void run() { while( true ) { // busy-wait for work while( true ) { if( workItem != NO_WORK ) break; } // do the work ... // wait for everyone else to finish barrier.await(); } } } Also works well functionally (it does what it should). blocksize | system | user | cycles/sec 256k 1.9% 85% 1.30 64k 2.2% 81% 6.3 16k 4.2% 62% 33 4096 7.5% 40% 107 1024 10.4% 23% 210 256 12.0% 12.0% 310 64 11.9% 10.2% 550 16 12.2% 8.6% 741 For small work items, this increases throughput by a further 10% over the CyclicBarrier + wait/notify variant, which is not insignificant. But it is still much lower-throughput than V1 with the ExecutorService. V5 - ? So what is the best synchronization mechanism for such a (presumably not uncommon) problem? I am weary of writing my own sync mechanism to completely replace ExecutorService (assuming that it is too generic and there has to be something that can still be taken out to make it more efficient). It is not my area of expertise and I'm concerned that I'd spend a lot of time debugging it (since I'm not even sure my wait/notify and busy wait variants are correct) for uncertain gain. Any advice would be greatly appreciated.

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