One important point is that Mission Control is potentially not free to use on production environments. It is free for applications running in DEV &amp; QA and Oracle are not currently enforcing the charges for production applications (as of Nov 2014). However, their executives have made it clear this may change in time.

The JMX Console part of Java Mission Control is just like any other JMX console. I&#39;m of course biased, but in my opinion it&#39;s one of the more feature rich consoles available. The more unique part of JMC is the Java Flight Recorder part. 

JMC is targeting production systems, and is very careful to avoid introducing unnecessary overhead. With the Java Flight Recorder you can do production time profiling and diagnostics with an almost unmeasurable overhead.

What does &quot;Pending Restart&quot; mean? I have stopped and restarted my WebJob numerous times and that doesn&#39;t seem to fix it. Does it mean I have to restart my website? What caused my job to get in this state in the first place? Is there any way I can prevent this from happening in the future?

What Does Azure WebJob &quot;Pending Restart&quot; Mean?

This is what I am doing: [jsfiddle][1] 

The critical section is:

    position: function() {
      var container = $(this.getDOMNode());
      this._menu = $(this.refs.menu.getDOMNode());
      this._menu.appendTo(document.body).
          offset({
              top: container.offset().top + 
                  container.outerHeight(),
              left: container.offset().left
          });
    },
    restore: function() {
      this._menu.appendTo(this.getDOMNode());      
    },
    componentWillUpdate: function() {
      this.restore();
    },
    componentDidUpdate: function() {
      this.position();
    },
    componentDidMount: function() {
      this.position();
    },

This works great right now. I put the content back before the component updates on the assumption that React leaves the DOM alone between updates and won&#39;t miss it. In fact, React seems to be fine with moving content (if I remove `componentWillUpdate` and `componentDidUpdate`, the positioned element still updates!)

My question is how many of the resulting assumptions are safe (i.e., if I assume these things, will my code break in a future version of React?):

 * React does not care if DOM is moved around between updates as long as you put it back in `componentWillUpdate`.
 * React event handlers will still work on elements that have been moved.
 * React will merge any inline styles you ask it with styles already on the element (even if it did not set them.)
 * React will update DOM it has rendered, even if you move that DOM somewhere else in the document!

The last one seems somewhat extreme and magical to me, but has some great implications if it holds.


  [1]: http://jsfiddle.net/iamnoah/pTrrw/

React: How much can I manipulate the DOM React has rendered?

Other than the more &#39;advanced&#39; GUI from Java mission control, how are they different?

At first glance they seem to offer very similar functionality (Interpreting JMX data and Memory/CPU profiling).

However, as they are both shipped with the JDK (I&#39;m using JDK 1.7.0_51 SE) I&#39;m assuming there are significant differences, otherwise they would be combined into a single solution. Especially as this increases the size of the JDK significantly.

Is Java Mission Control ultimately going to replace JVisualVM in the future?

What are the differences between JVisualVM and Java Mission Control?

Other than the more 'advanced' GUI from Java mission control, how are they different?
At first glance they seem to offer very similar functionality (Interpreting JMX data and Memory/CPU profiling).
However, as they are both shipped with the JDK (I'm using JDK 1.7.0_51 SE) I'm assuming there are significant differences, otherwise they would be combined into a single solution. Especially as this increases the size of the JDK significantly.
Is Java Mission Control ultimately going to replace JVisualVM in the future?

**This question is outdated and no longer relevant. I have since moved to Gradle for my project build and can no longer verify that answers do or do not work.**

I&#39;ve run into a few issues with Maven. Let me first describe my project setup:

    Framework
    |  -- Apache Commons Math 3.0
    |  -- Bouncy Castle 1.5
    |  -- etc.. (lots more)
    |________
    |        Client
    |        | -- GUI libraries
    |        | -- etc.
    |
    |________
             Server
             | -- Server Libraries
             | -- etc.


So essentially I have a framework that contains most dependancies and then two projects, &quot;Server&quot; and &quot;Client&quot; that contain their own BUT also the framework as a dependancy (being a module of Framework.). I installed the Framework project into my local repository and both my projects can see the Framework-Native code (aka my own logic). HOWEVER they don&#39;t seem to be able to use any of the dependancies of the Framework Project. When trying to build either of the &quot;child&quot;-projects I get this:

    Invalid POM for de.r2soft.empires.framework:Framework:jar:Alpha-1.2, 
    transitive dependencies (if any) will not be available, 
    enable debug logging for more details 

I&#39;ve tried to find the reason behind this (or better yet a solution) but haven&#39;t found anything that fixed my issues. Hope someone here can help. My maven version seems to be 3.2.1 (that&#39;s what -version tells me anyways)

Here are my framework-pom.xml and the client-pom.xml on pastebin:

Framework: http://pastebin.com/cceZECaT

Client: http://pastebin.com/1Cuxve5F

Help is appreciated.

The POM for &lt;name&gt; is invalid, transitive dependencies (if any) will not be available

I recently moved to Java 8 to, hopefully, deal with local and zoned times more easily.

However, I&#39;m facing an, in my opinion, simple problem when parsing a simple date.

    public static ZonedDateTime convertirAFecha(String fecha) throws Exception {
    	DateTimeFormatter formatter = DateTimeFormatter.ofPattern(
    			ConstantesFechas.FORMATO_DIA).withZone(
    			obtenerZonaHorariaServidor());
    
    	ZonedDateTime resultado = ZonedDateTime.parse(fecha, formatter);
    	return resultado;
    }

In my case:

* fecha is &#39;15/06/2014&#39;
* ConstantesFechas.FORMATO_DIA is &#39;dd/MM/yyyy&#39;
* obtenerZonaHorariaServidor returns ZoneId.systemDefault()

So, this is a simple example. However, the parse throws this exception:

&gt; java.time.format.DateTimeParseException: Text &#39;15/06/2014&#39; could not
&gt; be parsed: Unable to obtain ZonedDateTime from TemporalAccessor:
&gt; {},ISO resolved to 2014-06-15 of type java.time.format.Parsed

Any tips? I&#39;ve been trying different combinations of parsing and using TemporalAccesor, but without any luck so far.

Unable to obtain ZonedDateTime from TemporalAccessor using DateTimeFormatter and ZonedDateTime in Java 8

In Java 8 three memory barrier instructions were added to `Unsafe` class ([source][1]):

    /**
     * Ensures lack of reordering of loads before the fence
     * with loads or stores after the fence.
     */
    void loadFence();

    /**
     * Ensures lack of reordering of stores before the fence
     * with loads or stores after the fence.
     */
    void storeFence();

    /**
     * Ensures lack of reordering of loads or stores before the fence
     * with loads or stores after the fence.
     */
    void fullFence();

If we define memory barrier with the following way (which I consider more or less easy to understand):

&gt; Consider X and Y to be operation types/classes that are subject for reordering,
&gt;
&gt; **`X_YFence()` is a memory barrier instruction that ensures that all operations of type X before the barrier completed before any operation of type Y after the barrier is started.**

We can now &quot;map&quot; barrier names from `Unsafe` to this terminology:

* `loadFence()` becomes `load_loadstoreFence()`;
* `storeFence()` becomes `store_loadStoreFence()`;
* `fullFence()` becomes `loadstore_loadstoreFence()`;

Finally, **my question is** - why don&#39;t we have `load_storeFence()`, `store_loadFence()`, `store_storeFence()` and `load_loadFence()`?

My guess would be - they are not really neccesary, but I do not understand why at the moment. So, I&#39;d like to know reasons for not adding them. Guesses about that are welcome too (hope this doesn&#39;t cause this question to be offtopic as opinion-based, though).

Thanks in advance.

  [1]: http://openjdk.java.net/jeps/171

Java 8 Unsafe: xxxFence() instructions

I&#39;ve got a problem injecting the `Validator` into the spring application bean when attempting to validate a model using JSR-303 (hibernate-validator) 

My main configuration class is:

    @EnableAutoConfiguration
    @EnableWebMvc // &lt;---
    @EnableJpaRepositories(&quot;com.example&quot;)
    @EntityScan(&quot;com.example&quot;)
    public class MainConfiguration {


According to the javadocs:

	/**
	 * Provide a custom {@link Validator} instead of the one created by default.
	 * The default implementation, assuming JSR-303 is on the classpath, is:
	 * {@link org.springframework.validation.beanvalidation.LocalValidatorFactoryBean}.
	 * Leave the return value as {@code null} to keep the default.
	 */
	Validator getValidator();

Hibernate-validator is on the classpath.
I&#39;m trying to inject it into the Repository:


    @Repository
    public class UserRepositoryImpl implements UserRepositoryCustom    {
    
        @Autowired
        private Validator validator;



Exception being thrown:

     No qualifying bean of type [javax.validation.Validator] found for dependency:


**UPDATE:**

The partial work-around for this is to define this in the main configuration class:

      @Bean
        public Validator validator() {
    
            return new org.springframework.validation.beanvalidation.LocalValidatorFactoryBean();
        }

But integration tests (the ones which require `org.springframework.test.context.web.WebAppConfiguration;` annotation and use validation logic) fail.







Spring-Boot How to properly inject javax.validation.Validator

Is there any way to define static final variables (effectively constants) in a Java enum declaration?

What I want is to define in one place the string literal value for the BAR(1...n) values:
    
    @RequiredArgsConstructor
    public enum MyEnum {
        BAR1(BAR_VALUE),
        FOO(&quot;Foo&quot;),
        BAR2(BAR_VALUE),
        ...,
        BARn(BAR_VALUE);

        private static final String BAR_VALUE = &quot;Bar&quot;;

        @Getter
        private final String value;
    }

I got the following error message for the code above: **Cannot reference a field before it is defined**.

How to define static constants in a Java enum?

If I try to profile application, (which is prepared under Eclipse, but running from command line) with the help of VisualVM, I get the following error message

![enter image description here][1]

Simultaneously, the project folder is fouled with newly created class files. Although they are already existing in `target/classes`.

The project structure is Maven&#39;s, i.e. there is a foder `target/classes` in current directory and I us the following command to run the application

    java -Xmx16g -cp target/classes tests.Runner01

How to fix?

**UPDATE** 

The same occurs with conventional java project too.

Below it the picture of populated class files, which located where they should not 

![enter image description here][2]




  [1]: http://i.stack.imgur.com/GPhyQ.png
  [2]: http://i.stack.imgur.com/zuetp.png

Redefinition failed with error 62 while trying to profile an application

Can someone please explain me the difference between `Sleeping`, `Wait`, `Park`, and `Monitor` thread states in VisualVM.

![enter image description here][1]

This is what I have found:

`Running`: thread is still running. &lt;br /&gt;
`Sleeping`: thread is sleeping (method yield() was called on the thread object)&lt;br /&gt;
`Wait`: thread was blocked by a mutex or a barrier, and is waiting for another thread to release the lock&lt;br /&gt;
`Park`: parked threads are suspended until they are given a permit. Unparking a thread is usually done by calling method unpark() on the thread object&lt;br /&gt;
`Monitor`: threads are waiting on a condition to become true to resume execution

What I am unable to understand is the state Park, what actually suspends the thread? How do I detect in the code what has made the thread suspend its execution?

Can someone please guide me in this regard.

Thanks.


  [1]: http://i.stack.imgur.com/4WYvV.png

VisualVM - Thread States

I had to run `jmap` in order to take heap dump of my process. but `jvm` returned:

    Unable to open socket file: target process not responding or HotSpot VM not loaded
    The -F option can be used when the target process is not responding

So I used the `-F`:

    ./jmap -F -dump:format=b,file=heap.bin 10330
    Attaching to process ID 10331, please wait...
    Debugger attached successfully.
    Server compiler detected.
    JVM version is 24.51-b03
    Dumping heap to heap.bin ...

1. Using `-F`  is allright  for taking heap dump?
2. I am waiting 20 minutes and not finished yet. Any ideas why?

Running jmap getting Unable to open socket file

I was benchmarking some code, and I could not get it to run as fast as with [`java.math.BigInteger`][1], even when using the exact same algorithm.
So I copied [`java.math.BigInteger`][1] source into my own package and tried this:

    //import java.math.BigInteger;

    public class MultiplyTest {
    	public static void main(String[] args) {
	    	Random r = new Random(1);
     		long tm = 0, count = 0,result=0;
    		for (int i = 0; i &lt; 400000; i++) {
    			int s1 = 400, s2 = 400;
    			BigInteger a = new BigInteger(s1 * 8, r), b = new BigInteger(s2 * 8, r);
    			long tm1 = System.nanoTime();
    			BigInteger c = a.multiply(b);
    			if (i &gt; 100000) {
    				tm += System.nanoTime() - tm1;
    				count++;
    			}
    			result+=c.bitLength();
    		}
    		System.out.println((tm / count) + &quot;nsec/mul&quot;);
    		System.out.println(result); 
    	}
    }

When I run this (jdk 1.8.0_144-b01 on MacOS) it outputs:

    12089nsec/mul
    2559044166

When I run it with the import line uncommented:

    4098nsec/mul
    2559044166

It&#39;s almost three times as fast when using the JDK version of BigInteger versus my version, even if it&#39;s using the exact same code.

I&#39;ve examined the bytecode with javap, and compared compiler output when running with options:

    -Xbatch -XX:-TieredCompilation -XX:+PrintCompilation -XX:+UnlockDiagnosticVMOptions 
    -XX:+PrintInlining -XX:CICompilerCount=1

and both versions seem to generate the same code.
So is hotspot using some precomputed optimisations that I can&#39;t use in my code? I always understood that they don&#39;t.
What explains this difference?


  [1]: https://docs.oracle.com/javase/7/docs/api/java/math/BigInteger.html

Content Type	Original Author	Original Content on Stackoverflow
Question	GoldenJam	View Question on Stackoverflow
Solution 1 - Java	kittylyst	View Answer on Stackoverflow
Solution 2 - Java	Hirt	View Answer on Stackoverflow

What are the differences between JVisualVM and Java Mission Control?

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

React: How much can I manipulate the DOM React has rendered?

What Does Azure WebJob "Pending Restart" Mean?

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