To determine the class of an object simply call:

    someObject.getClass()

You can abbreviate this to `someObject.class` in most cases. However, if you use this on a `Map` it will try to retrieve the value with key &#39;class&#39;. Because of this, I always use `getClass()` even though it&#39;s a little longer.

If you want to check if an object implements a particular interface or extends a particular class (e.g. Date) use:

    (somObject instanceof Date)

or to check if the class of an object is *exactly* a particular class (not a subclass of it), use:

    (somObject.getClass() == Date)


Simple groovy way to check object type:  

    somObject in Date

Can be applied also to interfaces.

Just to add another option to D&#243;nal&#39;s answer, you can also still use the good old `java.lang.Object.getClass()` method.

You can use the Membership Operator isCase() which is another groovy way:

    assert Date.isCase(new Date())

`somObject instanceof Date`

should be 

`somObject instanceOf Date`




How can I display an infinity symbol (like the one in the picture) using HTML?

&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/c/c8/Infinite.svg/200px-Infinite.svg.png&quot; height=&quot;80&quot; alt=&quot;infinity symbol&quot; /&gt;


Infinity symbol with HTML

I was trying to edit an old commit message as explained [here][1]. 

The thing is that now, when I try to run `rebase -i HEAD~5` it says `interactive rebase already started`.

So then I try: `git rebase --continue` but got this error:

    error: Ref refs/heads/master is at 7c1645b447a8ea86ee143dd08400710c419b945b but expected c7577b53d05c91026b9906b6d29c1cf44117d6ba
    fatal: Cannot lock the ref &#39;refs/heads/master&#39;.

Any ideas?
 


  [1]: http://schacon.github.io/history.html

Change old commit message using `git rebase`

What is the best way to determine the data type in groovy? 

I&#39;d like to format the output differently if it&#39;s a date, etc. 

Groovy / grails how to determine a data type?

<p>What is the best way to determine the data type in groovy?</p>
<p>I'd like to format the output differently if it's a date, etc.</p>


I have a complex Gradle script that wraps up a load of functionality around building and deploying a number of NetBeans projects to a number of environments.

The script works very well, but in essence it is all configured through half a dozen maps holding project and environment information.

I want to abstract the tasks away into another file, so that I can simply define my maps in a simple build file, and import the tasks from the other file. In this way, I can use the same core tasks for a number of projects and configure those projects with a simple set of maps.

Can anyone tell me how I can import one Gradle file into another, in a similar manner to Ant&#39;s &lt;import&gt; task? I&#39;ve trawled Gradle&#39;s docs to no avail so far.

**Additional Info**

After Tom&#39;s response below, I thought I&#39;d try and clarify exactly what I mean.

Basically I have a Gradle script which runs a number of subprojects. However, the subprojects are all NetBeans projects, and come with their own ant build scripts, so I have tasks in Gradle to call each of these.

My problem is that I have some configuration at the top of the file, such as:

```groovy
projects = [
    [name:&quot;MySubproject1&quot;, shortname: &quot;sub1&quot;, env:&quot;mainEnv&quot;, cvs_module=&quot;mod1&quot;],
    [name:&quot;MySubproject2&quot;, shortname: &quot;sub2&quot;, env:&quot;altEnv&quot;, cvs_module=&quot;mod2&quot;]
]
```
    
I then generate tasks such as:

```groovy
projects.each({
    task &quot;checkout_$it.shortname&quot; &lt;&lt; {
         // Code to for example check module out from cvs using config from &#39;it&#39;.
    }
})
```

I have many of these sort of task generation snippets, and all of them are generic - they entirely depend on the config in the projects list.

So what I want is a way to put this in a separate script and import it in the following sort of way:

```groovy
projects = [
    [name:&quot;MySubproject1&quot;, shortname: &quot;sub1&quot;, env:&quot;mainEnv&quot;, cvs_module=&quot;mod1&quot;],
    [name:&quot;MySubproject2&quot;, shortname: &quot;sub2&quot;, env:&quot;altEnv&quot;, cvs_module=&quot;mod2&quot;]
]

import(&quot;tasks.gradle&quot;) // This will import and run the script so that all tasks are generated for the projects given above.
```

So, in this example, tasks.gradle will have all the generic task generation code in, and will get run for the projects defined in the main build.gradle file. In this way, tasks.gradle is a file that can be used by all large projects that consist of a number of sub-projects with NetBeans ant build files.


How can I import one Gradle script into another?

In ruby, there is a indiom to create a array of strings like this:

    names = %w( lucas Fred Mary )

Is there something like that in groovy?

Array of strings in groovy

Is it possible to `break` from a Groovy `.each{Closure}`, or should I be using a classic loop instead?

Can you break from a Groovy &quot;each&quot; closure?

What is the best way to remove null items from a list in Groovy?

ex: `[null, 30, null]`

want to return: `[30]`

Remove null items from a list in Groovy

I am coding this with Groovy 

I am currently trying to convert a string that I have to a date without having to do anything too tedious. 

    String theDate = &quot;28/09/2010 16:02:43&quot;;
    def newdate = new Date().parse(&quot;d/M/yyyy H:m:s&quot;, theDate)


Output: 

    Tue Aug 10 16:02:43 PST 2010


The above code works just fine, however when my string changes to something like:

    String testDate = &quot;Tue Aug 10 16:02:43 PST 2010&quot;
    def newerdate = new Date().parse(&quot;d/M/yyyy H:m:s&quot;, testDate)

It tells me that &quot;there is no such value for Tue&quot;. I tried to throw an &#39;E&#39; in the parse for the date but it said the date was not able to be parsed.

Can someone explain how I should go about parsing the second example?
     

Groovy String to Date

Is it possible to achieve the following code?  I know it doesn&#39;t work, but I&#39;m wondering if there is a workaround?

    Type k = typeof(double);
    List&lt;k&gt; lst = new List&lt;k&gt;();

Creating a Generic&lt;T&gt; type instance with a variable containing the Type

In a non-static method I could use `this.GetType()` and it would return the `Type`. How can I get the same `Type` in a static method? Of course, I can&#39;t just write `typeof(ThisTypeName)` because `ThisTypeName` is known only in runtime. Thanks!

.NET: Determine the type of “this” class in its static method

I have a generic method 

    bool DoesEntityExist&lt;T&gt;(Guid guid, ITransaction transaction) where T : IGloballyIdentifiable;

How do I use the method in the following way:

    Type t = entity.GetType();
    DoesEntityExist&lt;t&gt;(entityGuid, transaction);

I keep receiving the foollowing compile error:
&gt; The type or namespace name &#39;t&#39; could
&gt; not be found (are you missing a using
&gt; directive or an assembly reference?)

    DoesEntityExist&lt;MyType&gt;(entityGuid, transaction);

works perfectly but I do not want to use an if directive to call the method with a separate type name every time.



Generics in C#, using type of a variable as parameter

I have two classes declared as below:

    class User
    {
    public:
      MyMessageBox dataMsgBox;
    };
    
    class MyMessageBox
    {
    public:
      void sendMessage(Message *msg, User *recvr);
      Message receiveMessage();
      vector&lt;Message&gt; *dataMessageList;
    };

When I try to compile it using gcc, it gives the following error:

&gt;MyMessageBox does not name a type

&quot;X does not name a type&quot; error in C++

What is the size of character in C and C++ ? As far as I know the size of char is 1 byte in both C and C++.

**[In C:][1]**

    #include &lt;stdio.h&gt;
    int main()
    {
        printf(&quot;Size of char : %d\n&quot;, sizeof(char));
        return 0;
    }

**[In C++:][2]**

    #include &lt;iostream&gt;
    int main()
    {
        std::cout &lt;&lt; &quot;Size of char : &quot; &lt;&lt; sizeof(char) &lt;&lt; &quot;\n&quot;;
        return 0;
    }

No surprises, both of them gives the output : `Size of char : 1`

Now we know that characters are represented as `&#39;a&#39;`,`&#39;b&#39;`,`&#39;c&#39;`,`&#39;|&#39;`,... So I just modified the above codes to these:

**In C:**

    #include &lt;stdio.h&gt;
    int main()
    {
        char a = &#39;a&#39;;
        printf(&quot;Size of char : %d\n&quot;, sizeof(a));
        printf(&quot;Size of char : %d\n&quot;, sizeof(&#39;a&#39;));
        return 0;
    }

 
**[Output:][3]**

    Size of char : 1
    Size of char : 4

**In C++:**

    #include &lt;iostream&gt;
    int main()
    {
        char a = &#39;a&#39;;
        std::cout &lt;&lt; &quot;Size of char : &quot; &lt;&lt; sizeof(a) &lt;&lt; &quot;\n&quot;;
        std::cout &lt;&lt; &quot;Size of char : &quot; &lt;&lt; sizeof(&#39;a&#39;) &lt;&lt; &quot;\n&quot;;
        return 0;
    }

**[Output:][4]**

    Size of char : 1
    Size of char : 1

**Why the `sizeof(&#39;a&#39;)` returns different values in C and C++?**

  [1]: https://web.archive.org/web/20000000000000/http://www.ideone.com/e3Yo1Kyf
  [2]: https://web.archive.org/web/20000000000000/http://www.ideone.com/uG4Qodfo
  [3]: https://web.archive.org/web/20000000000000/http://www.ideone.com/Y11gm1lw
  [4]: https://web.archive.org/web/20000000000000/http://www.ideone.com/b00pdptc

Content Type	Original Author	Original Content on Stackoverflow
Question	Jack BeNimble	View Question on Stackoverflow
Solution 1 - Groovy	Dónal	View Answer on Stackoverflow
Solution 2 - Groovy	Michal Z m u d a	View Answer on Stackoverflow
Solution 3 - Groovy	Pops	View Answer on Stackoverflow
Solution 4 - Groovy	Ibrahim.H	View Answer on Stackoverflow
Solution 5 - Groovy	Mike N	View Answer on Stackoverflow

Groovy / grails how to determine a data type?

Groovy Problem Overview

Groovy Solutions

Solution 1 - Groovy

Solution 2 - Groovy

Solution 3 - Groovy

Solution 4 - Groovy

Solution 5 - Groovy

Change old commit message using `git rebase`

Infinity symbol with HTML

Attributions