In an application I am developing RESTful API and we want the client to send data as JSON. Part of this application requires the client to upload a file (usually an image) as well as information about the image.

I&#39;m having a hard time tracking down how this happens in a single request.  Is it possible to Base64 the file data into a JSON string?  Am I going to need to perform 2 posts to the server? Should I not be using JSON for this?

As a side note, we&#39;re using Grails on the backend and these services are accessed by native mobile clients (iPhone, Android, etc), if any of that makes a difference.

Posting a File and Associated Data to a RESTful WebService preferably as JSON

I am yet to find a high-level definition of Spring beans that I can understand. I see them referenced often in Grails documentation and books, but I think that understanding what they are would be beneficial. So what are Spring beans? How can they be used? Do they have something to do with Dependency Injection?

What in the world are Spring beans?

I am building a grails-app with IntelliJ 9.0 and I am a huge fan of the CTR+TAB shortcut that switches between active editors.

However, by default, IntelliJ keeps ONLY 10 active editors opened at the same time. It is clearly not enough for me.

Do you know, if possible, how I can configure my IDE to have more active editors opened at the same time ?


How to increase the maximum number of opened editors in IntelliJ?

I need to perform a null or empty check on a collection; I think that `!members?.empty` is incorrect.  Is there a groovier way to write the following?

    if (members &amp;&amp; !members.empty) {
        // Some Work
    }

Checking if a collection is null or empty in Groovy

I get the following error when using a primitive attribute in my grails domain object:

    Null value was assigned to a property of primitive type setter of MyDomain.myAttribute
     org.hibernate.PropertyAccessException: Null value was assigned to a property of primitive type setter of MyDomain.myAttribute
	at grails.orm.HibernateCriteriaBuilder.invokeMethod(HibernateCriteriaBuilder.java:1077)


Why do I get a &quot;Null value was assigned to a property of primitive type setter of&quot; error message when using HibernateCriteriaBuilder in Grails

I&#39;m working on extending the [Grails Clojure plugin][1] in [Grails 2.0.0][2] (and 2.1.0-SNAPSHOT) and I wanted to update it to [Clojure 1.3.0][3] and add [clojure.tools.logging][4]. 

Clojure throws an exception during compilation of a 
*proxy* of a `ByteArrayOutputStream` in `clojure.tools.logging`&#39;s log-stream function: 

`ClassCastException: clojure.asm.Type cannot be cast to clojure.lang.IFn`

( https://gist.github.com/a6ae681c37091a3d2379 )

I went and removed `clojure.tools.logging` and wrote a stripped down *proxy* of `Object`: 


`(proxy [java.lang.Object] [] (toString [] &quot;proxy&#39;s toString&quot;))` 

and it also threw that same `ClassCastException` and message. 

I tried to print a *macroexpand-1* of the *proxy* and got the same thing. 

I reverted to Clojure 1.2.0 and *proxy* worked fine again. 

I tried a number of incarnations of 1.4.0 and they exhibit the same behavior as 1.3.0. 
1.2.1 also throws some sort of exception but I&#39;m trying to hit 1.3.0 so I didn&#39;t spend much time with that.

The stack trace points to the &#39;gen-method function defined in one of the *let* forms of `generate-proxy` in `core_proxy.clj`. 

I added a small smattering of `println`&#39;s around there to see if I could catch what was happening. Maybe this next statement will betray a huge misunderstanding of the reader on my part but simply adding those `println`s changed the compile time behavior in a way I totally didn&#39;t expect. The exception location and exception type completely changed, even though all the Clojure tests in `mvn package` continue to pass.

For instance, just adding a single `println` to gen-method right before it starts generating bytecode caused Clojure to throw 

`ClassCastException: clojure.lang.PersistentArrayMap cannot be cast to java.lang.Class` 

( https://gist.github.com/5a7a40929a6c4a104bd5 )

I&#39;ve seen various other errors depending on where I put the `println`(s) but this is the most prevalent.

Obviously some aspect of Grails and Clojure are not meshing correctly here, but I am not seeing the connection. At first I suspected ASM incompatibility but since Clojure has its own ASM namespace, I can&#39;t see that being the issue. But maybe I&#39;m wrong, I&#39;ve been staring at `clojure.lang.Compiler`, *proxy* and *generate-proxy* for days now trying to get this to work and I&#39;ve pretty much stopped making forward progress because I&#39;ve run out of steam :(

I apologize for the lack of links. You can copy and paste from below:

Grails Clojure - [github.com/grails-plugins/grails-clojure][5]

Clojure Tools Logging - [github.com/clojure/tools.logging/blob/master/src/main/clojure/clojure/tools/logging.clj][6] line 133 is the &#39;proxy 


  [1]: http://grails.org/plugin/clojure
  [2]: http://grails.org/doc/2.0.x/guide/introduction.html
  [3]: http://clojure.org/downloads
  [4]: https://github.com/clojure/tools.logging
  [5]: http://github.com/grails-plugins/grails-clojure
  [6]: http://github.com/clojure/tools.logging/blob/master/src/main/clojure/clojure/tools/logging.clj

Clojure 1.2.1/1.3/1.4 &#39;proxy generated in Grails 2.0.0 runtime fails. 1.2.0 is fine

Nowadays I hear a lot about &quot;Groovy on Grails&quot; and I want to know more about it:

 - What is Groovy?
 - What is Grails?
 - What kind of applications are built using Groovy on Grails?

What are &quot;Groovy&quot; and &quot;Grails&quot;  and what kinds of applications are built using them?

I want to pass the `userName` from a list of `userName`s a logged in user clicks on to twitter bootstrap `modal`.
I am using **grails** with **angularjs**, where data is rendered via **angularjs**.

&lt;h2&gt;Configuration&lt;/h2&gt;
**My grails view page `encouragement.gsp` is** 

    &lt;div ng-controller=&quot;EncouragementController&quot;&gt;
        &lt;g:render template=&quot;encourage/encouragement_modal&quot; /&gt;
        &lt;tr ng-cloak
                      ng-repeat=&quot;user in result.users&quot;&gt;
                       &lt;td&gt;{{user.userName}}&lt;/rd&gt;
                       &lt;td&gt;
                          &lt;a class=&quot;btn btn-primary span11&quot; href=&quot;#encouragementModal&quot; data-toggle=&quot;modal&quot;&gt;
    				            Encourage
    				       &lt;/a&gt;
                      &lt;/td&gt;
                    &lt;/tr&gt;
&lt;/div&gt;
**My `encourage/_encouragement_modal.gsp` is** 

    &lt;div id=&quot;encouragementModal&quot; class=&quot;modal hide fade&quot;&gt;
      &lt;div class=&quot;modal-header&quot;&gt;
        &lt;button type=&quot;button&quot; class=&quot;close&quot; data-dismiss=&quot;modal&quot;
          aria-hidden=&quot;true&quot;&gt;&amp;times;&lt;/button&gt;
        &lt;h3&gt;Confirm encouragement?&lt;/h3&gt;
      &lt;/div&gt;
      &lt;div class=&quot;modal-body&quot;&gt;
          Do you really want to encourage &lt;b&gt;{{aModel.userName}}&lt;/b&gt;?
      &lt;/div&gt;
      &lt;div class=&quot;modal-footer&quot;&gt;
        &lt;button class=&quot;btn btn-info&quot;
          ng-click=&quot;encourage(&#39;${createLink(uri: &#39;/encourage/&#39;)}&#39;,{{aModel.userName}})&quot;&gt;
          Confirm
        &lt;/button&gt;
        &lt;button class=&quot;btn&quot; data-dismiss=&quot;modal&quot; aria-hidden=&quot;true&quot;&gt;Never Mind&lt;/button&gt;
      &lt;/div&gt;
    &lt;/div&gt;

So, how can I pass `userName` to `encouragementModal`?

How to pass parameters to a modal?

I&#39;m using grails 2.0.4. And I want to use port:8090 instead of 8080 for localhost. So need help to change the port to 8090 permanently.

How to change grails localhost port?

In Windows, `JAVA_HOME` must point to the JDK installation folder (so that `JAVA_HOME/bin` contains all executables and `JAVA_HOME/libs` contains all default `jar` libraries).

If I download Sun&#39;s JDK bundle and installs it in Linux, it is the same procedure.

However, I need to use Kubuntu&#39;s default OpenJDK package. The problem is that all executables are placed in `/usr/bin`. But the jars are placed in `/usr/share/java`. Since they are not under the same `JAVA_HOME` folder I&#39;m having trouble with Grails and maybe there will be trouble with other applications that expect the standard Java structure.

1. If I use:

        JAVA_HOME=/usr

 All applications and scripts that want to use any Java executable can use the standard procedure `call $JAVA_HOME/bin/executable`. However, since the jars are in a different place, they are not always found (example: in grails I&#39;m getting `ClassDefNotFound` for `native2ascii`).

2. On the other hand, if I use:

        JAVA_HOME=/usr/share/java

 None of the Java executables (`java`, `javac`, etc.) can be found.

So, what is the correct way of handling the `JAVA_HOME` variable in a Debian-based Linux?

Thanks for your help,
Luis

What is the correct target for the JAVA_HOME environment variable for a Linux OpenJDK Debian-based distribution?

I want to log in the console or in a file, all the queries that Grails does, to check performance.

I had configured [this][1] without success.

Any idea would help.

  [1]: http://www.grails.org/FAQ#Q:%20How%20can%20I%20turn%20on%20logging%20for%20hibernate%20in%20order%20to%20see%20SQL%20statements,%20input%20parameters%20and%20output%20results?



How to log SQL statements in Grails

This is half rant, half question.

Is it worth using Grails? I&#39;m trying to develop a relatively simple database-driven web application. My expertise is in Java, so naturally Grails seemed like a good choice. At first I thought of using Spring, JPA and Hibernate, but I’ve used that previously and have run into all sorts of tedious configuration and coding work. Grails advertises itself as solving this.

My biggest frustration with Grails is all of the little things that don&#39;t work. What I mean is that it doesn&#39;t work as one would intuitively think it should. It&#39;s very rough around the edges. I run into problems constantly. Sometimes it&#39;s my lack of Grails understanding — other times I&#39;ve discovered legitimate Grails bugs.

One major issue is the lack of good Eclipse integration. There is a Groovy and Grails plugin, but it doesn&#39;t do much other than syntax highlighting. Calling Groovy from Java and vice versa is very painful to [configure][1]. Not having good IDE support is a major bummer.

What happens is I sit down trying to develop my web application. At the end of the day I realize that I&#39;ve spent about 85% of the day debugging Grails-related issues. If it isn&#39;t Eclipse problems then it&#39;s [eager loading][2], [fetching in the view][3], [one-to-many relationships][4], [weird empty file bug behavior][5], [a weird property/getter bug][6] — it just goes on and on. This is just a sample of the issues I ran into today. My last sit-down with Grails yielded a whole bunch of different issues.

I sometimes wonder if it&#39;s worth it. I&#39;m curious if others have experienced this. Are there people actually using Grails to productively crank out a web application? Are there other frameworks for rapid web development that I should be considering?


  [1]: http://brainflush.wordpress.com/2008/05/03/grails-and-eclipse-not-so-groovy/
  [2]: https://stackoverflow.com/questions/397145/grails-eager-fetch-doesnt-retrieve-all-data
  [3]: https://stackoverflow.com/questions/396703/how-to-reference-a-grails-domain-class-fields-from-outside-of-the-grails-contro
  [4]: https://stackoverflow.com/questions/396667/in-grails-need-to-define-a-set-for-one-to-many-relationship
  [5]: https://stackoverflow.com/questions/396514/after-grails-clean-i-cant-run-app
  [6]: https://stackoverflow.com/questions/395586/grails-getsomethingint-i-method-doesnt-comiple

Is Grails worth it?

Method to copy entire directory contents to another directory in java or groovy?

Copy entire directory contents to another directory?

My Grails app uses a h2 database in dev mode (the default behaviour for Grails apps). The DB connection settings in `DataSource.groovy` are

    dataSource {
        pooled = true
        jmxExport = true
        driverClassName = &quot;org.h2.Driver&quot;
        username = &quot;sa&quot;
        password = &quot;&quot;
        dbCreate = &quot;create-drop&quot; // one of &#39;create&#39;, &#39;create-drop&#39;, &#39;update&#39;, &#39;validate&#39;, &#39;&#39;
        url = &quot;jdbc:h2:mem:devDb;MVCC=TRUE;LOCK_TIMEOUT=10000;DB_CLOSE_ON_EXIT=FALSE&quot;
    }

I&#39;m trying to setup a connection for this database using IntelliJ IDEA&#39;s database client tools. I start off creating the connection like so

![enter image description here][1]

Then in the following dialog, I enter the JDBC URL

![enter image description here][2]

And choose all available databases on the &quot;Schemas &amp; Tables&quot; tab.

![enter image description here][3]

The &quot;Test Connection&quot; button indicates success, but as you can see from the red circle, no tables are found. It seems like I&#39;ve correctly setup a connection to the h2 server, but not the schema itself.

BTW, I try to setup this connection once the app is running, so I&#39;m sure that the schema/tables do actually exist.

  [1]: http://i.stack.imgur.com/x44oQ.png
  [2]: http://i.stack.imgur.com/wBdGD.png
  [3]: http://i.stack.imgur.com/JP4OS.png

Connect to H2 database using IntelliJ database client

I got this error message:

&gt; error: Found shared references to a collection: Person.relatedPersons

When I tried to execute `addToRelatedPersons(anotherPerson)`:

    person.addToRelatedPersons(anotherPerson);
    anotherPerson.addToRelatedPersons(person);
    
    anotherPerson.save();
    person.save();

My domain:

    Person {
    
     static hasMany = [relatedPersons:Person];
    
    }

any idea why this happens ?



Found shared references to a collection org.hibernate.HibernateException

SpringSource (now VMWare) has two very similar technologies: Grails and Spring Roo. I have been using Grails, but I see that SpringSource is actively working on something that is a competitor for that technology and that makes me worried about the future of Grails.

Does anyone know how these technologies relate, are they going to be merged, or one of them will be abandoned?

Besides, are there any important technical differences betweent Grails and Roo?

Grails vs Roo - why SpringSource is pushing two very similar technologies?

I know this is a [duplicate][1], however, the Grails world has moved on considerably since that question was asked more than a year ago, as has the IDE support in Eclipse, so please don&#39;t just blindly close it.  

I thought the answer was yes and have embarked on a new project with [Grails 1.2.0][2] and have flirted with the Groovy/Grails bits of the [STS Eclipse Integration][3].

I think the question deserves revisiting after a year of Grails evolution, when the answer was definitely mixed.

So, as an experienced Java web developer I have these questions and would appreciate *my assumptions* being challenged:

 - Is Grails now worth it vs. Ruby or roll your own?
 - Has it overcome its buggy start?  
 - Does it really confer rapid development benefits?  *(I admit I am struggling now I am past the extensive baseline configuration to make my bespoke app which is not list and page oriented)*
 - Does it perform for real world production apps?  *(It feels heavy)*
 - Is the Eclipse plug-in better than it was and fit for purpose? *(I think not yet)*

Thanks

**EDIT:**
I am learning as I go and I have a couple of significant gripes to make about living with the framework - rather than framework capabilities themselves.  I am adding these because I think they should be considerations and are based on my experience and opinion, and may help someone who is trying to decide whether to go grails.  I may also be showing my lack of experience with the framework, so none of this is meant as out and out criticisms.  I am an experienced developer and this is what I have found:  

**Debugging is really hard**.  In fact it is almost impossible, especially as a beginner in the framework, which is when you need your trusty debugger friend the most.  I have spent way more time than I ought to tracking down problems of syntactical errors in some part of the code to do with referring to domain fields which cause silent failures somewhere in the stack.

**Logging is frankly awful**.  You have two modes, &quot;nothing useful&quot; and &quot;an inordinate amount of useless stuff&quot;. My debug log was 128Mb after a single page request and contains nothing about my error.  The whole issue of logging needs reconsideration in the framework in my opinion.

**The STS Eclipse IDE is of marginal value**.  Other than syntax hilighting it is not much use.  You can&#39;t debug the code so it is a glorified editor.  The code hints are patchy and there is no GSP support at all as far as I can see.  It also is the slowest Eclipse plug-in I have on my desktop - by about 2 minutes to start up.  It is shockingly slow.  I have reverted to a text editor (which you&#39;ll notice all the online tutorial videos do too) and some custom syntax hilighting.

**I have some serious concerns about performance**.  A bit too early to say, but I am already finding myself tweaking the database because of hibernate.  Perhaps that&#39;s to be expected, but I am really having to keep my domain model simple for the conventions to yield performant queries.

And one last one, the convention that your logical domain model and your physical database model should be identical is not a smart default and unlikely ever to be the case in the real world.  I know you can separate the two, but it creates a degree of complexity which I think could be avoided if the conventions were extended.  There is inadequate documentation about composition and [what you need to do to make it work in practice][4].  


  [1]: https://stackoverflow.com/questions/397228/is-grails-worth-it
  [2]: http://www.grails.org/1.2+Release+Notes
  [3]: http://www.grails.org/STS+Integration
  [4]: https://stackoverflow.com/questions/2123871/how-do-i-save-a-composite-field-value-in-grails-gsp/

Is Grails (now) worth it?

I need to calculate the **time elapsed from one specific date till now** and display it with the same format as StackOverflow questions, i.e.:

    15s ago
    2min ago
    2hours ago
    2days ago
    25th Dec 08

Do you know how to achieve it with the Java **[Joda-Time][1] library**? Is there a helper method out there that already implements it, or should I write the algorithm myself?


  [1]: http://www.joda.org/joda-time/

How to calculate elapsed time from now with Joda-Time?

I have obtained the latest Grails 2.0 milestone, and I am seeing a deprecation warning for the `ConfigurationHolder` class:

    org.codehaus.groovy.grails.commons.ConfigurationHolder

The deprecation message simply says &quot;Use dependency injection instead&quot; which is not very helpful to me. I understand dependency injection, but how can I wire up a bean with the proper Grails configuration so I can access it at runtime?  I need to access the configuration from places other than my Controllers and Tags (such as `BootStrap`).  


How to access Grails configuration in Grails 2.0?

What&#39;s the difference between `build`, `runtime`, and `compile`, in `BuildConfig.groovy` (1.3.7)


    grails.project.dependency.resolution = {
    
        plugins {
            build &quot;acme:acme-cache:latest.integration&quot;
        }
    
        dependencies {
            build &quot;com.foo.bar:foobar:1.0.5&quot;       
            runtime &quot;org.apache.httpcomponents:httpclient:4.0.3&quot;
            compile(&quot;com.thoughtworks.xstream:xstream:1.3.1&quot;)
        }
    }







Grails BuildConfig.groovy, difference between build, compile, and runtime?

I have this VM with tomcat, java, and grails in it. I&#39;ve been getting permgen errors so I looked around and found the solution:

    set JAVA_OPTS=&quot;-Xms256m -Xmx1024m -XX:PermSize=512m -XX:MaxPermSize=512m&quot;

I use SSH to access the vm and type the arguments above. I suppose that would fix the problem. Thing is, I wanted to make sure that I did it correctly. So I searched again on how I could check the current permSize and this is the solution I got:

    jinfo -flag MaxPermSize 6444

6444 is the pid, and as a response, I got this.

    -XX:MaxPermSize=85983232

Question: Is the value of the maxPermSize in bytes? because, if it is, then that would mean that the java_opts command didn&#39;t work. I am expecting to get 512m but 85983232 bytes = 82 mb.. Or am I seeing it wrong..? Can anybody enlighten me on this? D:

How do I properly set the permgen size?

In one of controllers in my Grails application I&#39;m preserving a parameter value in a session variable like this:

    session.myVariable = params.myValue

After that, I can access the saved value from different controllers/GSP-pages as long as I actively use the app. However, if I don&#39;t use my app for a while, even though my browser window is still open, the session variable looses it&#39;s value.

Does this happens because the session expires? I was under impression that a session lives until the browser window is still open, but apparently I was wrong.

What should I do to ensure all session variables I define in my Grails app don&#39;t expire until the browser is closed? Is there any way to set session timeout manually?

Thank you in advance for your answers!


How to configure a session timeout for Grails application?


I am trying to crop/resize user profile image using jquery plugin namely crop.js which sends user image as base64 via ajax to my controller as 

    $.ajax({
             type: &quot;post&quot;,
             dataType: &quot;json&quot;,
             url: &quot;${g.createLink(controller: &#39;personalDetail&#39;, action:&#39;uploadUserImage&#39;)}&quot;,
             data: { avatar: canvas.toDataURL() }

            });

 but I unable to decode this base64
    
    &#39;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAPAAAADwCAYAAAA+VemSAAAgAEl...==&#39; 
string as Image,Can you guys guide me how can I save my base64 string as image on my server?.

Convert base64 string to image

When deploying a large Java webapp (&gt;100 MB .war) I&#39;m currently use the following deployment process:

* The application .war file is expanded locally on the development machine.
* The expanded application is rsync:ed from the development machine to the live environment.
* The app server in the live environment is restarted after the rsync. This step is not strictly needed, but I&#39;ve found that restarting the application server on deployment avoids &quot;java.lang.OutOfMemoryError: PermGen space&quot; due to frequent class loading.

Good things about this approach:

* The rsync minimizes the amount of data sent from the development machine to the live environment. Uploading the entire .war file takes over ten minutes, whereas an rsync takes a couple of seconds.

Bad things about this approach:

* While the rsync is running the application context is restarted since the files are updated. Ideally the restart should happen after the rsync is complete, not when it is still running.
* The app server restart causes roughly two minutes of downtime.

I&#39;d like to find a deployment process with the following properties:

* Minimal downtime during deployment process.
* Minimal time spent uploading the data.
* If the deployment process is app server specific, then the app server must be open-source.

Question:

* &lt;b&gt;Given the stated requirements, what is the optimal deployment process?&lt;/b&gt;


Best practices for deploying Java webapps with minimal downtime?

Grails can be a bit of a bear to debug with its long stack dumps.  Getting to the source of the problem can be tricky.  I&#39;ve gotten burned a few times in the BootStrap.groovy doing &quot;def foo = new Foo(a: a, b: b).save()&quot;, for example.  What are your favorite tricks for debugging Grails apps?

What are your favorite Grails debugging tricks?

I have a controller that needs to return a 404 page and status code on certain conditions. I can&#39;t seem to find out how to do this in Grails. A coworker recommended this method:

    response.sendError(HttpServletResponse.SC_NOT_FOUND)

which works perfectly fine, but it&#39;s not very Grails-like. I know Rails&#39; render method take a status argument, but Grails&#39; render has no such functionality. Is there something I&#39;m missing, what&#39;s the best way to accomplish this?

How can I return a 404/50x status code from a Grails Controller?

I want to parse JSON data which is coming in like:

    {
       &quot;212315952136472&quot;: {
          &quot;id&quot;: &quot;212315952136472&quot;,
          &quot;name&quot;: &quot;Ready&quot;,
          &quot;picture&quot;: &quot;http://profile.ak.fbcdn.net/hprofile-ak-snc4/195762_212315952136472_4343686_s.jpg&quot;,
          &quot;link&quot;: &quot;http://www.hityashit.com/movie/ready&quot;,
          &quot;likes&quot;: 5,
          &quot;category&quot;: &quot;Movie&quot;,
          &quot;description&quot;: &quot;Check out the reviews of Ready on  http://www.hityashit.com/movie/ready&quot;
       }
    }

The code I am using is:

    JSONElement userJson = JSON.parse(jsonResponse)
    userJson.data.each {
        Urls = it.link
    }

But I am not able to get anything assigned to `Urls`. Any suggestions?

how to parse json using groovy

I see { } are used for closures, and then I believe when a $ is put in front of braces, it is simply doing a variable substitution within a string.  I can&#39;t find the documentation on how the $ works in the reference ... hard to search on it unfortunately, and the Groovy String documentation is lacking in introducing this.  Can you please point me to the documentation and/or explain the &quot;$&quot; operator in Groovy -- how all it can be used?   Does Grails extend it at all beyond Groovy?


Using &quot;$&quot; in Groovy

Suppose a simple Grails domain class:

    class Account {
        String countryId;

        String userName;

        String password;

        static constraints = {
            ...???...
        }
    }

It is required that user names are unique for a particular &lt;i&gt;countryId&lt;/i&gt;, thus there must be a &lt;i&gt;unique&lt;/i&gt; contraint on two columns. How to express this in the &lt;i&gt;constraints&lt;/i&gt; definition? 

Grails domain class: unique constraint for multiple columns

I have the HQL where I trying to get artifacts that have no classification (when active is 0)

    artifacts = Artifact.findAll(&quot;FROM Artifact WHERE id NOT IN ( SELECT artifact_id FROM Classification WHERE active = 1) AND document_id = :docid&quot;,[docid:document.id], [max:limit, offset:startIndex]);
    							
Whenever I run I get the error



    java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.IdentNode 
     \-[IDENT] IdentNode: &#39;artifact_id&#39; {originalText=artifact_id}
   
Classificaiton definition:

    class Classification {
    
        public static final String USER_DEFAULT = &quot;USER&quot;
        public static final String USER_SYSTEM = &quot;SYSTEM&quot;
    
        TaxonomyNode node
        String artifactId 
        Boolean active
        String createdBy
        String updatedBy
        Date dateCreated
        Date lastUpdated
       
    
        static constraints = {
            node nullable:false, blank:false
            artifactId nullable:false, blank:false, unique: [&#39;node&#39;]
            active nullable: false, blank: false
            createdBy nullable:false, blank:false
            updatedBy nullable:false, blank:false
        }
    
        static mapping = {
            id generator:&#39;sequence&#39;, params:[sequence:&#39;classification_seq&#39;]
            artifactId index: &#39;classify_by_artifact_node&#39;
            node index: &#39;classify_by_artifact_node&#39;
            active defaultValue: &quot;1&quot;
        }
    }
You can refer to previous problems I faced to understand what exactly I am trying to do [Quest 1][1] and [Quest 2][2]


  [1]: https://stackoverflow.com/questions/26469285/sql-to-hql-query-grails
  [2]: https://stackoverflow.com/questions/26467420/how-to-check-null-or-not-valid-in-hql-query

No data type for node: org.hibernate.hql.internal.ast.tree.IdentNode HQL

With Grails there are several ways to do the same thing.

Finds all of domain class instances:

    Book.findAll()
    Book.getAll()
    Book.list()
    
Retrieves an instance of the domain class for the specified id:

    Book.findById(1)
    Book.get(1)

When do you use each one? Are there significant differences in performance?

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