You can&#39;t do this in pure java. But if you really need it -- you can use JNI to call native code which do the job. This is the place to start with:

http://ovatman.blogspot.com/2010/02/using-java-jni-to-set-thread-affinity.html

http://blog.toadhead.net/index.php/2011/01/22/cputhread-affinity-in-java/

**UPD:** After some thinking, I&#39;ve decided to create my own class for this: [ThreadAffinity.java][1] It&#39;s JNA-based, and very simple -- so, if you want to use it in production, may be you should spent some time making it more stable, but for benchmarking and testing it works well as is.

**UPD 2:** There is another [library][2] for working with thread affinity in java. It uses same method as previously noted, but has another interface


  [1]: http://tools.assembla.com/Behemoth/browser/Tests/JAVA/test/src/main/java/test/threads/ThreadAffinity.java
  [2]: https://github.com/OpenHFT/Java-Thread-Affinity

I know it&#39;s been a while, but if anyone comes across this thread, here&#39;s how I solved this problem. I wrote a script that would do the following:

1. &quot;jstack -l &lt;PID&gt;&quot;
2. Take the results, find the &quot;nid&quot;&#39;s of the threads I want to manually lock down to cores.
3. Taskset those threads. 



You might want to take a look at https://github.com/peter-lawrey/Java-Thread-Affinity/blob/master/src/test/java/com/higherfrequencytrading/affinity/AffinityLockBindMain.java

IMO, this &lt;b&gt;will not&lt;/b&gt; be possible unless you use native calls. JVM is supposed to be platform independent, any system calls done to achieve this will not result in a portable code.

It&#39;s not possible (at least with plain Java).

You can use [thread pools][1] to limit the amount of threads (and therefore cores) used for different types of work, but there is no way to specify a core to use.

There is even the (small) possibility that your Java runtime doesn&#39;t support native threading for your OS or hardware. In this case, [green threads][2] are used and only one core will be used for the whole JVM.


  [1]: http://java.sun.com/javase/6/docs/api/java/util/concurrent/ThreadPoolExecutor.html
  [2]: http://en.wikipedia.org/wiki/Green_threads

What is the type of string literal in C? Is it `char *` or `const char *` or `const char * const`?

What about C++?


What is the type of string literals in C and C++?

I&#39;m creating graphs in pgf/tikz. When I use these in my document they are scaled, several are in minipage/subfig like environments. When this happens the font sizes are scaled with the graphics making them very small or unreadable. I&#39;ve been through the manual but have so far been unsuccessful in my attempts to control this.

Is there a way to set the font size directly? What options are there?

One aswer given below shows how to how to use the \tikzstyle font option to specify the font size within the tikzpicture environment.

Right now I am using:

    \beginppgfgraphicnamed{graph}
    \input{graph.tex}
    \endpgfgraphicnamed

The tikzpicture environment is used in the input file. Are there anyways to specify font size in the setup I&#39;m using? Is this perhaps the issue? The graph.tex file is generated automatically via another program.

*In addition to setting font size for individual graphics it would be ideal to have a parameter to globally set font size for all tikz graphics?* I guess the issue is the scaling in *minipage* or *subfig*.

Many thanks,

Jay

How to control font sizes in pgf/tikz graphics in latex?

Does anybody know of a way to lock down individual threads within a Java process to specific CPU cores (on Linux)? I&#39;ve done this in C, but can&#39;t find how to do this in Java. My instincts are that this will require a JNI call, but I was hoping someone here might have some insight or might have done it before.

Thanks!

Java thread affinity

<p>Does anybody know of a way to lock down individual threads within a Java process to specific CPU cores (on Linux)? I've done this in C, but can't find how to do this in Java. My instincts are that this will require a JNI call, but I was hoping someone here might have some insight or might have done it before.</p>
<p>Thanks!</p>


Eclipse&#39;s &quot;problems&quot; tab is displaying this error:

&gt; Description: Java compiler level does not match the version of the installed Java project facet.  
&gt; Resource: groupping  
&gt; Path: [blank]  
&gt; Location: Unknown  
&gt; Type: Faceted Project Problem (Java Version Mismatch)

My `pom.xml` has this setting:

    &lt;plugins&gt;
        &lt;plugin&gt;
            &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
            &lt;artifactId&gt;maven-compiler-plugin&lt;/artifactId&gt;
            &lt;configuration&gt;
                &lt;source&gt;1.6&lt;/source&gt;
                &lt;target&gt;1.6&lt;/target&gt;
            &lt;/configuration&gt;
        &lt;/plugin&gt;
    &lt;/plugins&gt;

Where else could the settings be mismatched?

&quot;Faceted Project Problem (Java Version Mismatch)&quot; error message

In Java, how can you pass a type as a parameter (or declare as a variable)?  

I don&#39;t want to pass an *instance* of the type but the type itself (eg. int, String, etc).

In C#, I can do this:

    private void foo(Type t)
    {
        if (t == typeof(String)) { ... }
        else if (t == typeof(int)) { ... }
    }
    
    private void bar()
    {
        foo(typeof(String));
    }


Is there a way in Java without passing an *instance* of type t?  
Or do I have to use my own int constants or enum?  
Or is there a better way?

Edit: Here is the requirement for foo:  
Based on type t, it generates a different short, xml string.  
The code in the if/else will be very small (one or two lines) and will use some private class variables.

How to pass a type as a method parameter in Java

How do you clear the string buffer in Java after a loop so the next iteration uses a clear string buffer?

Clearing a string buffer/builder after loop

Is there any out-of-the-box, easy to implement, standard pagination component/tag-lib or code-sample available for pagination in Spring MVC?

How to implement pagination in Spring MVC 3

I&#39;m having a problem trying to run an Android app which, up until adding a second external library to its build path, was working fine. Since having added the scoreninja jar, I now get a **NoClassDefFoundError** when I try to run the app.

Here&#39;s the message:

    02-11 21:45:26.154: ERROR/AndroidRuntime(3654): java.lang.NoClassDefFoundError: com.scoreninja.adapter.ScoreNinjaAdapter

As all of the build scripts are generated by the Android tools (?), I&#39;m not sure what else I can do other than cleaning and rebuilding or restarting eclipse (I have already tried all three). Does anyone know how I can amend this?

NoClassDefFoundError - Eclipse and Android

I&#39;m trying to use Java&#39;s `ThreadPoolExecutor` class to run a large number of heavy weight tasks with a fixed number of threads. Each of the tasks has many places during which it may fail due to exceptions.

I&#39;ve subclassed `ThreadPoolExecutor` and I&#39;ve overridden the `afterExecute` method which is supposed to provide any uncaught exceptions encountered while running a task. However, I can&#39;t seem to make it work.

For example:

    public class ThreadPoolErrors extends ThreadPoolExecutor {
    	public ThreadPoolErrors() {
    		super(	1, // core threads
    				1, // max threads
    				1, // timeout
    				TimeUnit.MINUTES, // timeout units
    				new LinkedBlockingQueue&lt;Runnable&gt;() // work queue
    		);
    	}
    	
    	protected void afterExecute(Runnable r, Throwable t) {
    		super.afterExecute(r, t);
    		if(t != null) {
    			System.out.println(&quot;Got an error: &quot; + t);
    		} else {
    			System.out.println(&quot;Everything&#39;s fine--situation normal!&quot;);
    		}
    	}
    	
    	public static void main( String [] args) {
    		ThreadPoolErrors threadPool = new ThreadPoolErrors();
    		threadPool.submit( 
    				new Runnable() {
    					public void run() {
    						throw new RuntimeException(&quot;Ouch! Got an error.&quot;);
    					}
    				}
    		);
    		threadPool.shutdown();
    	}
    }

The output from this program is &quot;Everything&#39;s fine--situation normal!&quot; even though the only Runnable submitted to the thread pool throws an exception. Any clue to what&#39;s going on here?

Thanks!

Handling exceptions from Java ExecutorService tasks

In MSDN, the description of the Thread.Abort() method says: &quot;Calling this method **usually** terminates the thread.&quot; 

Why not ALWAYS? 

In which cases it doesn&#39;t terminate the thread? 

Are there any other possibility to terminate threads?

C# Thread Termination and Thread.Abort()

I want to run a thread for some fixed amount of time. If it is not completed within that time, I want to either kill it, throw some exception, or handle it in some way. How can it be done?

One way of doing it as I figured out from [this thread](http://groups.google.com.br/group/comp.lang.java.programmer/msg/0fea9dd5f0117a7f)
is to use a TimerTask inside the run() method of the Thread.

Are there any better solutions for this?

&amp;nbsp;  
EDIT: Adding a bounty as I needed a clearer answer. The ExecutorService code given below does not address my problem. Why should I sleep() after executing (some code - I have no handle over this piece of code)? If the code is completed and the sleep() is interrupted, how can that be a timeOut?

The task that needs to be executed is not in my control. It can be any piece of code. The problem is this piece of code might run into an infinite loop. I don&#39;t want that to happen. So, I just want to run that task in a separate thread. The parent thread has to wait till that thread finishes and needs to know the status of the task (i.e whether it timed out or some exception occured or if its a success). If the task goes into an infinite loop, my parent thread keeps on waiting indefinitely, which is not an ideal situation.

How to timeout a thread

Yes, I have read many materials related to operating system. And I am still reading. But it seems all of them are describing the process and thread in a &quot;abstract&quot; way, which makes a lot of high level elabration on their behavior and logic orgnization. **I am wondering what are they *physically*?** In my opinion, they are just some in-memory &quot;data structures&quot; which are maintained and used by the kernel codes to facilitate the execution of program. For example, operating system use *some process data structure (PCB)* to describe the aspects of the process assigned for a certain program, such as its priority, its address space and so on.  Is this all right?

What is process and thread?

I have always read that creating threads is expensive.  
I also know that you cannot rerun a thread.


I see in the doc of `Executors` class:

&gt; Creates a thread pool that creates new threads as needed, but will reuse previously constructed threads when they are available.


Mind the word &#39;reuse&#39;.


How do thread pools &#39;reuse&#39; threads? 

java thread reuse

When using the Spring 3.0 capability to annotate a scheduled task, I would like to set the `fixedDelay` as parameter from my configuration file, instead of hard-wiring it into my task class, like currently...

	@Scheduled(fixedDelay = 5000)
	public void readLog() {
            ...
	}

Unfortunately it seems that with the means of the Spring Expression Language (SpEL) `@Value` returns a String object which in turn is not able to be auto-boxed to a long value as required by the `fixedDelay` parameter.

How to parameterize @Scheduled(fixedDelay) with Spring 3.0 expression language?

Is there some cron like library that would let me schedule some function to be ran at certain time (15:30 for example, not x hours from now etc)? If there isn&#39;t this kind of library how this should be implemented? Should I just set callback to be called every second and check the time and start jobs scheduled for the time or what?

Is there a job scheduler library for node.js?

I&#39;m reading the [Spring 3.0 doc][1]s regarding scheduling. I&#39;m leaning towards Spring&#39;s JobDetailBean for Quartz. However, the **@Scheduled** annotation has captured my eye. It appears this is another way of scheduling task using the Spring Framework. Based on the docs, Spring provides three way of scheduling:

 1. @Scheduled
 2. Via Quartz
 3. Via JDK Timer

I have no interest in the JDK Timer. Why should I choose @Scheduled over Quartz? (When I mention Quartz I mean using Spring&#39;s bean wrapper for Quartz).

Let&#39;s say my use case is complex enough that I will be communicating to a third-party web service to import and export data at specified intervals.

  [1]: http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/scheduling.html

Spring Scheduling: @Scheduled vs Quartz

I use ScheduledExecutorService to execute a method periodically.

p-code:

    ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
    ScheduledFuture&lt;?&gt; handle =
    	    scheduler.scheduleWithFixedDelay(new Runnable() {
    	         public void run() { 
    	             //Do business logic, may Exception occurs
    	         }
    	    }, 1, 10, TimeUnit.SECONDS);


My question:

How to continue the scheduler, if `run()` throws Exception? 
Should I try-catch all Exception in method `run()`? Or any built-in callback method to handle the Exception? Thanks!


ScheduledExecutorService Exception handling

## Situation

I have a Runnable. I have a class that schedules this Runnable for execution using a ScheduledExecutorService with [scheduleWithFixedDelay](http://download.oracle.com/javase/1,5.0/docs/api/java/util/concurrent/ScheduledExecutorService.html#scheduleWithFixedDelay%28java.lang.Runnable,%20long,%20long,%20java.util.concurrent.TimeUnit%29).

## Goal

I want to alter this class to schedule the Runnable for fixed delay execution _either_ indefinitely, _or_ until it has been run a certain number of times, depending on some parameter that is passed in to the constructor.

If possible, I would like to use the same Runnable, as it is conceptually the same thing that should be &quot;run&quot;.

## Possible approaches

### Approach #1

Have two Runnables, one that cancels the schedule after a number of executions (which it keeps a count of) and one that doesn&#39;t:

    public class MyClass{
        private ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();

        public enum Mode{
            INDEFINITE, FIXED_NO_OF_TIMES
        }

        public MyClass(Mode mode){
            if(mode == Mode.INDEFINITE){
                scheduler.scheduleWithFixedDelay(new DoSomethingTask(), 0, 100, TimeUnit.MILLISECONDS);
            }else if(mode == Mode.FIXED_NO_OF_TIMES){
                scheduler.scheduleWithFixedDelay(new DoSomethingNTimesTask(), 0, 100, TimeUnit.MILLISECONDS);
            }
        }
        
        private class DoSomethingTask implements Runnable{
            @Override
            public void run(){
                doSomething();
            }
        }
        
        private class DoSomethingNTimesTask implements Runnable{
            private int count = 0;
    
            @Override
            public void run(){
                doSomething();
                count++;
                if(count &gt; 42){
                    // Cancel the scheduling.
                    // Can you do this inside the run method, presumably using
                    // the Future returned by the schedule method? Is it a good idea?
                }
            }
        }
        
        private void doSomething(){
            // do something
        }
    }

I would rather just have one Runnable for the execution of the doSomething method. Tying the scheduling to the Runnable feels wrong. What do you think about this?

### Approach #2

Have a single Runnable for the execution of the code that we want to run periodically. Have a separate scheduled runnable that checks how many times the first Runnable has run and cancels when it gets to a certain amount. This may not be accurate, as it would be asynchronous. It feels a bit cumbersome. What do you think about this?

### Approach #3

Extend ScheduledExecutorService and add a method &quot;scheduleWithFixedDelayNTimes&quot;. Perhaps such a class already exists? Currently, I&#39;m using `Executors.newSingleThreadScheduledExecutor();` to get my ScheduledExecutorService instance. I would presumably have to implement similar functionality to instantiate the extended ScheduledExecutorService. This could be tricky. What do you think about this?

### No scheduler approach [Edit]

I could not use a scheduler. I could instead have something like:

    for(int i = 0; i &lt; numTimesToRun; i++){
        doSomething();
        Thread.sleep(delay);
    }

And run that in some thread. What do you think of that? You could potentially still use the runnable and call the run method directly.

---

Any suggestions welcome. I&#39;m looking for a debate to find the &quot;best practice&quot; way of achieving my goal.

Content Type	Original Author	Original Content on Stackoverflow
Question	Dave	View Question on Stackoverflow
Solution 1 - Java	BegemoT	View Answer on Stackoverflow
Solution 2 - Java	Dave	View Answer on Stackoverflow
Solution 3 - Java	Vaibhav Kamble	View Answer on Stackoverflow
Solution 4 - Java	questzen	View Answer on Stackoverflow
Solution 5 - Java	Hardcoded	View Answer on Stackoverflow

Java thread affinity

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Solution 3 - Java

Solution 4 - Java

Solution 5 - Java

How to control font sizes in pgf/tikz graphics in latex?

What is the type of string literals in C and C++?

Attributions