You can see your facets via Right click on your project-&gt;properties-&gt;Project Facets,

Here you can see my facets for an example web application:
![here][1]

I think your *Java* facet does not match with the installed one. I&#39;m suspicious that facet is at version 1.5. Please check it. 

  [1]: http://i.stack.imgur.com/eBm7e.png

Add-on:Open the Navigator view, expand the .settings folder, open the file org.eclipse.wst.common.project.facet.core.xml and manually set the Java version to 1.6.

Right click on your project-&gt;properties-&gt;Project Facets,

This will show your current version of java for your project facet.

In my case I had the correct version for my facet but not my compiler,
So had to **right click on project-&gt;properties-&gt;Java Compiler**

Then under Compiler compliance level drop list and change to version of project facet.


its simple.. in Problems infotab, rightclick on error desc and select quickfix... choose facet version upgrade.. 






I got this issue in IBM RAD tool eclipse It got resolved following below.

* Right click on project
* Properties
* Project facets
* Configuration (select Default configuration for WebSphere application server v7.0 )
* Apply

I have a div on the left hand side which includes the business hours and weather. I would like that div to scroll down and up according to how the user scrolls. So it would follow and move up and down with the page. How would I attempt this? This is my website [judystropicalgarden.com][1]


  [1]: http://judystropicalgarden.com

Thanks

How do you make a div follow as you scroll?

What&#39;s the difference between sizeof and alignof?

    #include &lt;iostream&gt;

    #define SIZEOF_ALIGNOF(T) std::cout&lt;&lt; sizeof(T) &lt;&lt; &#39;/&#39; &lt;&lt; alignof(T) &lt;&lt; std::endl
    
    int main(int, char**)
    {
            SIZEOF_ALIGNOF(unsigned char);
            SIZEOF_ALIGNOF(char);
            SIZEOF_ALIGNOF(unsigned short int);
            SIZEOF_ALIGNOF(short int);
            SIZEOF_ALIGNOF(unsigned int);
            SIZEOF_ALIGNOF(int);
            SIZEOF_ALIGNOF(float);
            SIZEOF_ALIGNOF(unsigned long int);
            SIZEOF_ALIGNOF(long int);
            SIZEOF_ALIGNOF(unsigned long long int);
            SIZEOF_ALIGNOF(long long int);
            SIZEOF_ALIGNOF(double);
    }

will output

1/1
1/1
2/2
2/2
4/4
4/4
4/4
4/4
4/4
8/8
8/8
8/8

I think I don&#39;t get what the alignment is...?

What&#39;s the difference between sizeof and alignof?

I made a simple Java Google AppEngine application called Guestbook in Eclipse 3.7 and am trying to run it. However, I am encountering an error that lacks a quick fix:

    Description	Resource	Path	Location	Type
    Java compiler level does not match the version of the installed Java project facet.
    Guestbook		Unknown	Faceted Project Problem (Java Version Mismatch)

I tried navigating to &lt;i&gt;Project | Properties&lt;/i&gt; to change my project facet. However, I could not find a setting that dealt with &quot;facet.&quot;

![enter image description here][1]

What does &quot;installed Java project facet&quot; mean, and how do I fix this?


  [1]: http://i.stack.imgur.com/2N4Mp.png

Why doesn&#39;t my java compiler level match my installed project facet?

I made a simple Java Google AppEngine application called Guestbook in Eclipse 3.7 and am trying to run it. However, I am encountering an error that lacks a quick fix:
<pre><code class="hljs language-sql">Description	Resource	Path	Location	Type
Java compiler level does not match the version of the installed Java project facet.
Guestbook		Unknown	Faceted Project Problem (Java Version Mismatch)
</code></pre>
I tried navigating to Project | Properties to change my project facet. However, I could not find a setting that dealt with "facet."
<img src="http://i.stack.imgur.com/2N4Mp.png" alt="enter image description here">
What does "installed Java project facet" mean, and how do I fix this?

I&#39;ve been using Eclipse as my IDE. I also use it to export my application into a JAR file. When I look at my classes in the JAR file, a few of my classes contain the name of that class, a dollar sign, then a number. For example:
```java
Find$1.class 
Find$2.class
Find$3.class
Find.class
```

I&#39;ve noticed it does this on bigger classes. Is this because the classes get so big, it compiles it into multiple classes? I&#39;ve googled and looked on multiple forums, and search the Java documentation but have not found anything even related to it. Could someone explain?

java compiled classes contain dollar signs

&gt; **Possible Duplicate:**  
&gt; [What does List&amp;lt;?&amp;gt; mean in java generics?](https://stackoverflow.com/questions/1844770/what-does-list-mean-in-java-generics)  
&gt; [What does the question mark in Java generics&amp;#39; type parameter mean?](https://stackoverflow.com/questions/3009745/what-does-the-question-mark-in-java-generics-type-parameter-mean)  

&lt;!-- End of automatically inserted text --&gt;

Apologies but it was difficult trying to search for `&lt;?&gt;`.

What does &lt;?&gt; mean in regards to Java generics? I understand `&lt;A extends B&gt;` and `&lt;A super B&gt;`, but I have never seen this question mark on its own before.

Generics what does &lt;?&gt; actually mean?

I am reviewing the concept of inner classes in java. so far from what I&#39;ve understood and applied java inner classes has a link or access to the methods and fields of its outer/ enclosing class.

My Question: 
&lt;ol&gt;
&lt;li&gt;When should create or define an inner class? &lt;/li&gt;
&lt;li&gt;are inner classes considered to be called as &quot;Helper classes&quot; ?&lt;/li&gt;
&lt;li&gt;What are the indicators for you to make an inner class and what&#39;s their other purpose?&lt;/li&gt;&lt;/ol&gt;

What are the purposes of inner classes

I need to save the phone&#39;s timezone in the format [+/-]hh:mm

I am using TimeZone class to deal with this, but the only format I can get is the following:

    PST -05:00
    GMT +02:00

I would rather not substring the result, is there any key or option flag I can set to only get the value and not the name of that timezone (GMT/CET/PST...)?

Get TimeZone offset value from TimeZone without TimeZone name

Why in Java you&#39;re able to add Strings with the + operator, when String is a class?  In the`String.java` code I did not find any implementation for this operator. Does this concept violate object orientation?

How does the String class override the + operator?

I downloaded the [Eclipse Juno 4.2 classic bundle][1], and saw that `Help &gt; Marketplace...` was not available. AFAIK, this is provided by the [mpc plugin. On their website][2] however, I didn&#39;t see a trace of how to install the mpc client for Juno.

How can I add the Marketplace Client to the classic Juno bundle?


  [1]: http://eclipse.org/downloads/
  [2]: http://eclipse.org/mpc/

Install Marketplace plugin on Eclipse Juno

How can I enable the `assert` keyword in Eclipse?

    public class A
    {
        public static void main(String ... args)
        {
            System.out.println(1);
            assert false;
    	    System.out.println(2);
        }
    }

How to enable the Java keyword assert in Eclipse program-wise?

I started using Eclipse Juno a few days ago after using older versions for years.

There&#39;s one thing that&#39;s really bothering me: What do that percentages next to the methods in the auto-complete box mean?

![Screenshot of Percentages in Autocomplete Box][1]


  [1]: http://i.stack.imgur.com/i7RKi.png

Eclipse Autocomplete (percent sign, in Juno)

I can&#39;t compile/debug our Android app, because the localization files are not perfect yet.

My IDE&#39;s validation tool [Lint][1] create errors saying:

&gt; newCardsOrderVals is not translated in ar, bg, ca, cs

Compiling/installing/running with Ant works fine, but I would like to use my IDE to ease debugging.

Is there a way to turn off this particular check, or ideally make it a warning rather than an error?

I understand that before release we will really need to get localisation files right, but for the time being it is not a priority as the screens themselves are being modified very frequently.


  [1]: http://tools.android.com/tips/lint/

Lint: How to ignore &quot;&lt;key&gt; is not translated in &lt;language&gt;&quot; errors?

I am getting the above error: 

&gt; error opening trace file: No such file or directory (2)

when I run my android application on the emulator.  Can someone tell me what could be the possible reason for this?

I am using android-sdk-20 and below lines are added to AndroidManifest.xml

    &lt;uses-sdk android:minSdkVersion=&quot;14&quot; android:targetSdkVersion=&quot;15&quot; /&gt;

I have also added the line:

    &lt;uses-permission android:name=&quot;android.permission.WRITE_EXTERNAL_STORAGE&quot; /&gt;

since I thought that there may be some issue with writing to the sd card.


error opening trace file: No such file or directory (2)

How do I get nested templates like Jinja has in the python runtime. TBC what I mean is how do I have a bunch of templates inherit from a base templates, just filing in blocks of the base templates, like Jinja/django-templates does. Is it possible using just `html/template` in the standard library.

If that is not a possibility, what are my alternatives. Mustache seems to be an option but would I then be missing out on those nice subtle features of `html/template` like the context sensitive escaping etc.? What other alternatives are ther?

(Environment: Google App Engin, Go runtime v1, Dev - Mac OSx lion)

Thanks for reading.

Is it possible to have nested templates in Go using the standard library?

I have run into an interesting limit with the App Engine datastore.  I am creating a handler to help us analyze some usage data on one of our production servers.  To perform the analysis I need to query and summarize 10,000+ entities pulled from the datastore.  The calculation isn&#39;t hard, it is just a histogram of items that pass a specific filter of the usage samples.  The problem I hit is that I can&#39;t get the data back from the datastore fast enough to do any processing before hitting the query deadline.

I have tried everything I can think of to chunk the query into parallel RPC calls to improve performance, but according to appstats I can&#39;t seem to get the queries to actually execute in parallel. No matter what method I try (see below) it always seems that the RPC&#39;s fall back to a waterfall of sequential next queries.

Note: the query and analysis code does work, it just runs to slowly because I can&#39;t get data quickly enough from the datastore.

Background
==========
I don&#39;t have a live version I can share, but here is the basic model for the part of the system I am talking about:

    class Session(ndb.Model):
       &quot;&quot;&quot; A tracked user session. (customer account (company), version, OS, etc) &quot;&quot;&quot;
       data = ndb.JsonProperty(required = False, indexed = False)
   
    class Sample(ndb.Model):
       name      = ndb.StringProperty  (required = True,  indexed = True)
       session   = ndb.KeyProperty     (required = True,  kind = Session)
       timestamp = ndb.DateTimeProperty(required = True,  indexed = True)
       tags      = ndb.StringProperty  (repeated = True,  indexed = True)

You can think of the samples as times when a user makes use of a capability of a given name.  (ex: &#39;systemA.feature_x&#39;).  The tags are based upon customer details, system information, and the feature.  ex: [&#39;winxp&#39;, &#39;2.5.1&#39;, &#39;systemA&#39;, &#39;feature_x&#39;, &#39;premium_account&#39;]).  So the tags form a denormalized set of tokens that could be used to find samples of interest.

The analysis I am trying to do consists of taking a date range and asking how many times was a feature of set of features (perhaps all features) used per day (or per hour) per customer account (company, not per user).

So the input to the handler be something like:

 * Start Date
 * End Date
 * Tag(s)

Output would be:

    [{
       &#39;company_account&#39;: &lt;string&gt;,
       &#39;counts&#39;: [
          {&#39;timeperiod&#39;: &lt;iso8601 date&gt;, &#39;count&#39;: &lt;int&gt;}, ...
       ]
     }, ...
    ]

Common Code for Queries
=======================
Here is some code in common for all queries.  The general structure of the handler is a simple get handler using webapp2 that sets up the query parameters, runs the query, processes the results, creates data to return.

    # -- Build Query Object --- #
    query_opts = {}
    query_opts[&#39;batch_size&#39;] = 500   # Bring in large groups of entities

    q = Sample.query()
    q = q.order(Sample.timestamp)

    # Tags
    tag_args = [(Sample.tags == t) for t in tags]
    q = q.filter(ndb.query.AND(*tag_args))
    
    def handle_sample(sample):
       session_obj = sample.session.get()    # Usually found in local or memcache thanks to ndb
       count_key   = session_obj.data[&#39;customer&#39;]
       addCountForPeriod(count_key, sample.timestamp)


Methods Tried
=============
I have tried a variety of methods to try to pull data from the datastore as quickly as possible and in parallel.  The methods I have tried so far include:

A. Single Iteration
----------------
This is more of a simple base case to compare against the other methods.  I just build the query and iterate over all the items letting ndb do what it does to pull them one after the other.

    q = q.filter(Sample.timestamp &gt;= start_time)
    q = q.filter(Sample.timestamp &lt;= end_time)
    q_iter = q.iter(**query_opts)

    for sample in q_iter:
       handle_sample(sample)
    
B. Large Fetch
-----------
The idea here was to see if I could do a single very large fetch.

    q = q.filter(Sample.timestamp &gt;= start_time)
    q = q.filter(Sample.timestamp &lt;= end_time)
    samples = q.fetch(20000, **query_opts)

    for sample in samples:
       handle_sample(sample)


C. Async fetches across time range
-------------------------------
The idea here is to recognize that the samples are fairly well spaced across time so I can create a set of independent queries that split the overall time region into chunks and try to run each of these in parallel using async:

    # split up timestamp space into 20 equal parts and async query each of them
    ts_delta       = (end_time - start_time) / 20
    cur_start_time = start_time
    q_futures = []

    for x in range(ts_intervals):
       cur_end_time = (cur_start_time + ts_delta)
       if x == (ts_intervals-1):    # Last one has to cover full range
          cur_end_time = end_time

       f = q.filter(Sample.timestamp &gt;= cur_start_time,
                    Sample.timestamp &lt; cur_end_time).fetch_async(limit=None, **query_opts)
       q_futures.append(f)
       cur_start_time = cur_end_time

    # Now loop through and collect results
    for f in q_futures:
       samples = f.get_result()
       for sample in samples:
          handle_sample(sample)


D. Async mapping
-------------
I tried this method because the documentation made it sound like ndb may exploit some parallelism automatically when using the Query.map_async method.

    q = q.filter(Sample.timestamp &gt;= start_time)
    q = q.filter(Sample.timestamp &lt;= end_time)

    @ndb.tasklet
    def process_sample(sample):
       period_ts   = getPeriodTimestamp(sample.timestamp)
       session_obj = yield sample.session.get_async()    # Lookup the session object from cache
       count_key   = session_obj.data[&#39;customer&#39;]
       addCountForPeriod(count_key, sample.timestamp)
       raise ndb.Return(None)

    q_future = q.map_async(process_sample, **query_opts)
    res = q_future.get_result()
    

Outcome
=======

I tested out one example query to collect overall response time and appstats traces.  The results are:

A. Single Iteration
-------------------
real: 15.645s

This one goes sequentially through fetching batches one after the other and then retrieves every session from memcache.

![Method A appstats][1]

B. Large Fetch
--------------
real: 12.12s

Effectively the same as option A but a bit faster for some reason.

![Method B appstats][2]

C. Async fetches across time range
----------------------------------
real: 15.251s

Appears to provide more parallelism at the start but seems to get slowed down by a sequence of calls to next during iteration of the results.  Also doesn&#39;t seem to be able to overlap the session memcache lookups with the pending queries.

![Method C appstats][3]

D. Async mapping
----------------
real: 13.752s

This one is the hardest for me to understand.  It looks like it has q good deal of overlapping, but everything seems to stretch out in a waterfall instead of in parallel.

![Method D appstats][4]

Recommendations
===============
Based upon all this, what am I missing?  Am I just hitting a limit on App Engine or is there a better way to pull down large number of entities in parallel?  

I am at a loss as to what to try next.  I thought about rewriting the client to make multiple requests to app engine in parallel but this seems pretty brute force.  I would really expect that app engine should be able to handle this use case so I am guessing there is something I am missing.


Update
======
In the end I found that option C was the best for my case. I was able to optimize it to complete in 6.1 seconds.  Still not perfect, but much better.

After getting advice from several people, I found that the following items were key to understand and keep in mind:

  * Multiple queries can run in parallel
  * Only 10 RPC&#39;s can be in flight at once
  * Try to denormalize to the point that there are no secondary queries
  * This type of task is better left to map reduce and task queues, not real-time queries

So what I did to make it faster:

  * I partitioned the query space from the beginning based upon time.  (note: the more equal the partitions are in terms of entities returned, the better)
  * I denormalized the data further to remove the need for the secondary session query
  * I made use of ndb async operations and wait_any() to overlap the queries with the processing

I am still not getting the performance I would expect or like, but it is workable for now.  I just wish their was a better way to pull large numbers of sequential entities into memory quickly in handlers.


  [1]: http://i.stack.imgur.com/CSyR1.png
  [2]: http://i.stack.imgur.com/HsPZR.png
  [3]: http://i.stack.imgur.com/Ty2l4.png
  [4]: http://i.stack.imgur.com/JoNlN.png

Best practice to query large number of ndb entities from datastore

If I set &lt;code&gt;threadsafe: true&lt;/code&gt; in my &lt;code&gt;app.yaml&lt;/code&gt; file, what are the rules that govern when a new instance will be created to serve a request, versus when a new thread will be created on an existing instance?

If I have an app which performs something computationally intensive on each request, does multi-threading buy me anything? In other words, is an instance a multi-core instance or a single core?

Or, are new threads only spun up when existing threads are waiting on IO?


When does the App Engine scheduler use a new thread vs. a new instance?

I&#39;m trying to put breakpoints into the GoogleAppEngine sources (SDK 1.7.0) but IDEA Ultimate (11.0.2) just keeps telling me `Warning: No executable code found at line 482 in class com.google.appengine.api.memcache.AsyncMemcacheServiceImpl`.

I get this error message both when I run the code from unit tests and I start up the development server.

It&#39;s quite annonying. Anyway my sources are in an external (relative to both the IDEA home and the project home) directory, and my jar files are under the Appengine SDK lib dir.

My jar files are added as project library to the module, and my sources are attached to this library. I was playing around with module dependencies as well, but without any luck. Finally I decided to put this library into Compile scope, but that was a bad idea since the SDK provides these jars at runtime, so I decided to fall back to Provided scope.

I also played with the export checkbox on the module dependencies tab, but I think this is irrelevant, according to the [web help][1], export is only important when you have dependent modules and you want to make your library available in these modules as well.

Anyway, this question arised [4 years ago][2] also. So I&#39;m wondering now whether is it really so hard to solve this issue?

I&#39;m very disappointed now. I didn&#39;t have any problems with IDEA so far... I saw that this problem [arised to other people][3] as well, so this is not unique I guess.

Any help is appreciated.


----------
I edited my question due to my `javap` experiments below: It seems that the classes and the sources are **NOT** out of sync. I checked out the 1.7.0 related revision from SVN, and I&#39;m using the 1.7.0 SDK, so these should not be out of sync at all.

  [1]: http://www.jetbrains.com/idea/webhelp/dependencies-tab.html
  [2]: http://devnet.jetbrains.net/thread/276796
  [3]: https://stackoverflow.com/questions/11199282/set-a-breakpoint-inside-a-library-jar-in-intellij

Cannot set Java breakpoint in Intellij IDEA

Google created the V8 JavaScript engine: V8 compiles JavaScript source code directly into machine code when it is first executed.

Node.js is built on V8 - why is Google not offering any Node.js servers like Microsoft Azure?

Google App Engine would be a natural place to put Node.js.

Do you know why Google is not doing just that?

Content Type	Original Author	Original Content on Stackoverflow
Question	dangerChihuahua007	View Question on Stackoverflow
Solution 1 - Java	GokcenG	View Answer on Stackoverflow
Solution 2 - Java	java traniee	View Answer on Stackoverflow
Solution 3 - Java	kumar ravi	View Answer on Stackoverflow
Solution 4 - Java	Arjun Kushwah	View Answer on Stackoverflow

Why doesn't my java compiler level match my installed project facet?

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Solution 3 - Java

Solution 4 - Java

What's the difference between sizeof and alignof?

How do you make a div follow as you scroll?

Attributions