Of course you can.

1. install [File Watchers plugin](http://plugins.jetbrains.com/plugin/7177)
2. open &quot;Preferences-&gt;Tools-&gt;File Watchers&quot; &amp; Add a new watcher
3. set `File Type`: `Go`, `Program`: the abosolute path of `gofmt`, `Arguments`: `-w $FilePath$`
4. click `OK`

[![enter image description here][1]][1]


  [1]: http://i.stack.imgur.com/dDSyh.png

[Gogland EAP 16](https://blog.jetbrains.com/go/2017/10/18/gogland-eap-16-file-watcher-tons-of-new-inspections-smarter-navigate-to-test-and-more/) deprecated the On Save actions and replaced them with the [File Watchers plugin](https://plugins.jetbrains.com/plugin/7177-file-watchers).

If you have previously configured On Save actions, the IDE will prompt you to install the plugin and configure everything automatically. If you want to set it up from scratch yourself, check if you have File Watchers plugin and if not install it.

**Enable gofmt:**

1. Go to `Settings | Tools | File Watchers`.
2. Click the `+` button and select `go fmt`.
3. The default values are good. 
4. In Advance Options select:
  - Auto-save edited files to trigger the watcher
  - Trigger the watcher on external changes
5. Click ok!

[![Config][1]][1]

You can do the same for `goimports` and `gometalinter`.

  [1]: https://i.stack.imgur.com/vMXjQ.png

If you are using Gogland, you have an option On Save under Preferences

[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/3bDGd.png

**September 2021 Update.**

If you are using GoLand with the 2021.2 version and higher (July 2021), there are a few options to enable gofmt on save besides File Watchers.

- Enable _Run gofmt on code reformat_ under _Preferences/Settings | Editor | Code Style | Go | Other_.[![Run gofmt on code reformat option location][1]][1]
- Enable _Reformat code_ under _Preferences/Settings | Tools | Actions on Save_.[![enter image description here][2]][2]
- Press &lt;kbd&gt;Command&lt;/kbd&gt; + &lt;kbd&gt;S&lt;/kbd&gt; on macOS or &lt;kbd&gt;Ctrl&lt;/kbd&gt; + &lt;kbd&gt;S&lt;/kbd&gt; on Windows/Linux to save your changes.


  [1]: https://i.stack.imgur.com/cxZUH.png
  [2]: https://i.stack.imgur.com/vNG5L.png

Updated:

For new versions of the Goland:

1. open `File-&gt;Settings-&gt;Tools-&gt;File Watchers`
2. click on `+` button and choose `go fmt`
3. press `Ok`

Done :) 

Find the object matching with a Property value from a Collection using Java 8 Stream. 

    List&lt;Person&gt; objects = new ArrayList&lt;&gt;();

Person attributes -&gt; Name, Phone, Email. 

Iterate through list of Persons and find object matching email. 
Saw that this can be done through Java 8 stream easily. But that will still return a collection?

Ex: 

    List&lt;Person&gt; matchingObjects = objects.stream.
        filter(p -&gt; p.email().equals(&quot;testemail&quot;)).
        collect(Collectors.toList());

But I know that it will always have one unique object. Can we do something instead of &lt;code&gt;Collectors.toList&lt;/code&gt; so that i got the actual object directly.Instead of getting the list of objects. 
	
	

Java 8 Stream API to find Unique Object matching a property value

How does toggle a class in vue.js?

I have the following:

    &lt;th class=&quot;initial &quot; v-on=&quot;click: myFilter&quot;&gt;
    	&lt;span class=&quot;wkday&quot;&gt;M&lt;/span&gt;
    &lt;/th&gt;
    
    new Vue({
      el: &#39;#my-container&#39;,
      data: {},
      methods: {
    	myFilter: function(){
    	  // some code to filter users
    	}
      }
    });

When I click `&lt;th&gt;` tag I want to apply `active` as a class as follows:

    &lt;th class=&quot;initial active&quot; v-on=&quot;click: myFilter&quot;&gt;
    	&lt;span class=&quot;wkday&quot;&gt;M&lt;/span&gt;
    &lt;/th&gt;      

This needs to toggle i.e. each time its clicked it needs to add/remove the class.


Vue.js toggle class on click

I use IntelliJ with the Golang plugin.  Is it possible to configure the IDE to execute gofmt on file save?

Execute gofmt on file save in IntelliJ

<p>I use IntelliJ with the Golang plugin.  Is it possible to configure the IDE to execute gofmt on file save?</p>


I have so far avoided use of `log.Fatal`, but I recently co-incidentally discovered these questions; [code-coverage][1] and [tests-using-log-fatal][2].  

One of the comments from the 100 code coverage questions says: 

&gt; ... In the vast majority of cases `log.Fatal` should be only be used in main, or init functions (or possibly some things meant to be called only directly from them)&quot;

It go me thinking, so I began to look at the standard library code provided with Go.  There are lots of examples where the **test** code in the library makes use of `log.Fatal` which seems fine.  There are a few examples outside of the test code, such as in [`net/http`][3], shown below:

    // net/http/transport.go 
    func (t *Transport) putIdleConn(pconn *persistConn) bool {
        ...
    	for _, exist := range t.idleConn[key] {
    		if exist == pconn {
    			log.Fatalf(&quot;dup idle pconn %p in freelist&quot;, pconn)
    		}
        }
        ...
    }


If its is best practice to avoid use of `log.Fatal`, why is it used at all in the standard libraries, I would have expected just return an error.  It seems unfair to the user of the library to cause `os.Exit` to be called and not providing any chance for the application to clean-up.

I may be naive, so hence my question as a better practice would seem to be to call `log.Panic` which can be recovered and my theoretical long running stable application might have a chance of rising from the ashes.

So what would best-practise say for Go about when should log.Fatal should be used?


  [1]: https://stackoverflow.com/questions/33873305/how-to-get-100-code-coverage-in-golang
  [2]: https://stackoverflow.com/questions/30688554/how-to-test-go-function-containing-log-fatal
  [3]: https://golang.org/src/net/http/transport.go?h=log.Fatal#L408

Should a Go package ever use log.Fatal and when?

From the [docs](https://golang.org/pkg/encoding/json/#Marshal):

&gt; JSON cannot represent cyclic data structures and Marshal does not handle them. Passing cyclic structures to Marshal will result in an infinite recursion.

I&#39;ve experienced this situation, which results in a runtime panic.

What I&#39;m wondering is if anyone can provide a working program that demonstrates a non-panic situation where json.Marshal returns a non-nil error. The best answers would **clearly include the inputs used**.

What input will cause golang&#39;s json.Marshal to return an error?

I have this example code

	package main

	import (
		&quot;fmt&quot;
	)

	type IFace interface {
		SetSomeField(newValue string)
		GetSomeField() string
	}

	type Implementation struct {
		someField string
	}

	func (i Implementation) GetSomeField() string {
		return i.someField
	}

	func (i Implementation) SetSomeField(newValue string) {
		i.someField = newValue
	}

	func Create() IFace {
		obj := Implementation{someField: &quot;Hello&quot;}
		return obj // &lt;= Offending line
	}

	func main() {
		a := Create()
		a.SetSomeField(&quot;World&quot;)
		fmt.Println(a.GetSomeField())
	}

`SetSomeField` does not work as expected because its receiver is not of pointer type.

If I change the method to a pointer receiver, what I would expect to work, it looks like this:

	func (i *Implementation) SetSomeField(newValue string) { ...

Compiling this leads to the following error:

	prog.go:26: cannot use obj (type Implementation) as type IFace in return argument:
	Implementation does not implement IFace (GetSomeField method has pointer receiver)

How can I have the `struct` implement the interface **and** the method `SetSomeField` change the value of the actual instance without creating a copy?

Here&#39;s a hackable snippet:
https://play.golang.org/p/ghW0mk0IuU

I&#39;ve already seen this question https://stackoverflow.com/questions/29221854/in-go-golang-how-can-you-cast-an-interface-pointer-into-a-struct-pointer, but I cannot see how it is related to this example.

Golang method with pointer receiver

**Situation:**

I&#39;ve a slice of values and need to pick up a randomly chosen value from it. Then I want to concatenate it with a fixed string. This is my code so far:

    func main() {
	//create the reasons slice and append reasons to it
	reasons := make([]string, 0)
	reasons = append(reasons,
		&quot;Locked out&quot;,
		&quot;Pipes broke&quot;,
		&quot;Food poisoning&quot;,
		&quot;Not feeling well&quot;)

	message := fmt.Sprint(&quot;Gonna work from home...&quot;, pick a random reason )
    }

**Question:**

Is there a built-in function, which can help me by doing the &quot;*pick a random reason*&quot; part?

Pick a random value from a Go Slice

I&#39;m trying to solve &quot;The go programming lanaguage&quot; exercise #1.4 which requires me to have a set. I can create a set type but why doesn&#39;t the language come with one ? go, having come from google, where guava also originated, why didn&#39;t the language designers opt for adding support for fundamental data structures ? why force your users to create their own implementations for something so basic as a set ?

golang why don&#39;t we have a set datastructure

I am new to Intellij IDEA and Navigation Back(&lt;kbd&gt;Ctrl&lt;/kbd&gt;+&lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;Left&lt;/kbd&gt;) and&lt;br&gt; Forward(&lt;kbd&gt;Ctrl&lt;/kbd&gt;+&lt;kbd&gt;Alt&lt;/kbd&gt;+&lt;kbd&gt;Right&lt;/kbd&gt;) not working (tried in version 14 &amp; 15), &lt;br&gt;
but settings seems to be okey. How to make it work?

[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/bmiog.jpg

Navigation Back and Forward not working at Intellij IDEA

Having issues with the new LiveReload feature with Spring Boot devtools 1.3.  It doesn&#39;t reload on class changes.  I&#39;ve seen it demo&#39;d with IntelliJ @ Devoxx 2015. Is there some IDE setting I need to have enabled?  I&#39;m running via the IDE and not through Gradle.  I tried enabling &quot;Make project automatically&quot; which doesn&#39;t seem to help.

It seems to load correctly and is looking in the correct path

    2015-11-23 05:55:30.592 DEBUG 4700 --- [  restartedMain] o.s.boot.devtools.restart.Restarter      : Starting application com.myapp.Application with URLs [file:/E:/Projects/myapp/build/classes/main/, file:/E:/Projects/myapp/build/resources/main/]

My files

build.gradle

    buildscript {
        ext {
            springBootVersion = &#39;1.3.0.RELEASE&#39;
        }
        repositories {
            mavenCentral()
        }
        dependencies {
            classpath(&quot;org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}&quot;) 
        }
    }
    
    apply plugin: &#39;java&#39;
    apply plugin: &#39;eclipse-wtp&#39;
    apply plugin: &#39;idea&#39;
    apply plugin: &#39;spring-boot&#39; 
    apply plugin: &#39;war&#39;
    
    
    war {
        baseName = &#39;myapp&#39;
        version = &#39;0.0.1-SNAPSHOT&#39;
    }
    sourceCompatibility = 1.8
    targetCompatibility = 1.8
    
    repositories {
        mavenCentral()
        maven { url &quot;https://repo.spring.io/snapshot&quot; }
        maven { url &quot;https://repo.spring.io/milestone&quot; }
    }
    
    configurations {
        providedRuntime
    }
    
    dependencies {
        compile(&#39;org.springframework.boot:spring-boot-starter-actuator&#39;)
        compile(&#39;org.springframework.boot:spring-boot-devtools&#39;)
        compile(&#39;org.springframework.boot:spring-boot-starter-jdbc&#39;)
        compile(&#39;org.projectlombok:lombok&#39;)
        compile(&#39;org.springframework.boot:spring-boot-starter-web&#39;)
        compile(&#39;net.sourceforge.jtds:jtds:1.3.1&#39;);
        testCompile(&#39;org.springframework.boot:spring-boot-starter-test&#39;) 
    }
    
    dependencyManagement {
    	imports { 
    		mavenBom &quot;org.springframework.cloud:spring-cloud-starter-parent:Brixton.M3&quot; 
    	}
    }
    
    
    eclipse {
        classpath {
             containers.remove(&#39;org.eclipse.jdt.launching.JRE_CONTAINER&#39;)
             containers &#39;org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8&#39;
        }
    }
    
    task wrapper(type: Wrapper) {
        gradleVersion = &#39;2.7&#39;
    }
    


HelloWorldController

    @Controller
    public class HelloWorldController {

        @RequestMapping(&quot;/&quot;)
        @ResponseBody
        String home(){

            return &quot;Hello World test&quot;;
        }
    }

IntelliJ 15, SpringBoot devtools livereload not working

I have the following anonymous `Runnable` implementation.

    Runnable cronTask = new Runnable() {
           @Override
           public void run() {
              // do something
           }
    };

IntelliJ suggests that I replace it with a lambda expression. eg: 

    Runnable cronTask = () -&gt; {
         // multiple &quot;do something&quot; statements
    };

When using a single statement the syntax is:

    Runnable cronTask = () -&gt; doSomething();

What shortcut can I use to convert it?


How to change Runnable to lambda expression in Java with IntelliJ shortcut

**What is the equivalent of &lt;kbd&gt;CTRL&lt;/kbd&gt; + &lt;kbd&gt;SLASH&lt;/kbd&gt; on german keyboards?** 

I know that US-Layouts got that &lt;kbd&gt;/&lt;/kbd&gt; where the german &lt;kbd&gt; _ &lt;/kbd&gt; is, since I used an US-Layout for some time. But &lt;kbd&gt;CTRL&lt;/kbd&gt; + &lt;kbd&gt; _ &lt;/kbd&gt; just collapses a method.

Line-Comment shortcut on german keyboards

How does the `org.jetbrains.annotations.Contract` annotation work?
How does IntelliJ IDEA support it?

JetBrains&#39; @Contract annotation

I started learning golang and installed [GoLand from JetBrains][1]. I am reading the book _The Go Programming Language_, and in the first chapter author strongly recommends using the `gofmt` tool before each save. How I can follow this recommendation in GoLand?


  [1]: https://www.jetbrains.com/go/

goland how to use gofmt?

I am writing a project using the Go language with GoLand IDE by Jetbrains.

While writing the code, GoLand shows me an error message such as `&quot;unresolved reference&quot;` when the reference do exist and that the program compiles and runs correctly. 


Here is a similar (but simpler) example of some code that I have found here on stackoverflow (https://stackoverflow.com/questions/18042439/go-append-to-slice-in-struct) to reproduce this issue. 

The same error message appears even though I have implemented the methods just a few lines above. 

```
package main

import (
	&quot;fmt&quot;
)

type MyBoxItem struct {
	Name string
}

type MyBox struct {
	Items []MyBoxItem
}

func (box *MyBox) AddItem(item MyBoxItem) {
	box.Items = append(box.Items, item)
}

func main() {

	item1 := MyBoxItem{Name: &quot;Test Item 1&quot;}
	item2 := MyBoxItem{Name: &quot;Test Item 2&quot;}

	box := MyBox{}

	box.AddItem(item1)
	box.AddItem(item2)

	// checking the output
	fmt.Println(len(box.Items))
	fmt.Println(box.Items)
}
```

`box.AddItem(item1)` and `box.AddItem(item2)` are marked red as an error. If I move my cursor above it, it says `unresolved reference &quot;AddItem&quot;`. Yet the code compiles and runs. And as this was the solution to an other stackoverflow question, I do not think that the code is wrong. Furthermore I cannot find any mistakes in it.

[![enter image description here][1]][1]

[EDIT: I load the code from a remote server and edit it locally on my private pc. After finishing my changes, I upload it to the remote server (using GoLands tools like &quot;Browse remote host&quot;) and build and compile it there. After trying it out locally with the very same code, the error message sometimes is there and sometimes not. I am totally confused]


  [1]: https://i.stack.imgur.com/ibqt0.png

GoLand (JetBrains) shows error message &quot;Unresolved Reference&quot;. But Code compiles and runs

I have a weird issue that arose when I took a break from this project. Upon starting up Goland, I&#39;m riddled with errors when trying to run my project. 

The specific error, when building one of my packages, is: 
`start.go: package project/game is not in GOROOT (C:\Go\src\project\game)`

I have a folder structure as such under `C:\Users\username`
```
go
|-src
   |-project
        |-game
            |-entity
                 |-whatever.go
            |-game_stuff.go
        |-server
```
and my env vars are as such:
```
GOROOT=C:\Go 
GOPATH=C:\Users\ketchup\go 
```

for each of the modules (project/game/entity, project/game, project/server), I did a `git mod init`. 

When building, Goland will try to run this:
```
C:\Go\bin\go.exe build -o C:\Users\ketchup\AppData\Local\Temp\___go_build_project_server.exe project/server
```

and return the error.

Can anyone help me with this issue? Kind of lost since Goland was working fine the last time I opened it. Also not even sure what direction to look at - I&#39;m pretty new to Go and I&#39;m not really sure what documentation to look at :\  Thank you everyone! 

Content Type	Original Author	Original Content on Stackoverflow
Question	Myles McDonnell	View Question on Stackoverflow
Solution 1 - Go	yee	View Answer on Stackoverflow
Solution 2 - Go	David Miguel	View Answer on Stackoverflow
Solution 3 - Go	Arun Gopalpuri	View Answer on Stackoverflow
Solution 4 - Go	s0xzwasd	View Answer on Stackoverflow
Solution 5 - Go	Amin Shojaei	View Answer on Stackoverflow

Execute gofmt on file save in IntelliJ

Go Problem Overview

Go Solutions

Solution 1 - Go

Solution 2 - Go

Solution 3 - Go

Solution 4 - Go

Solution 5 - Go

Vue.js toggle class on click

Java 8 Stream API to find Unique Object matching a property value

Attributions