*Check out their home pages:*

[**SLF4J**][1] - The Simple Logging Facade for Java (SLF4J) serves as a **simple facade or abstraction**&lt;sup&gt;1&lt;/sup&gt; for various logging frameworks (e.g. java.util.logging, logback, log4j) allowing the end user to plug in the desired logging framework at deployment time.

&lt;sup&gt;1) It is not itself a logging library, but a generic interface to one of many logging libraries.&lt;/sup&gt;

[**Log4j 1.2**][2] - Welcome to Apache log4j, a **logging library** for Java.

[**Logback**][3] - Logback is **intended as a successor to the popular log4j** project, picking up where log4j leaves off.

[**Log4j 2**][4] - Apache Log4j 2 is an **upgrade to Log4j** that provides significant improvements over its predecessor, Log4j 1.x, and **provides many of the improvements available in Logback** while fixing some inherent problems in Logback&#39;s architecture.

*At least, that&#39;s what they all say of themselves.*


  [1]: http://www.slf4j.org/
  [2]: http://logging.apache.org/log4j/1.2/
  [3]: http://logback.qos.ch/
  [4]: http://logging.apache.org/log4j/2.x/

This link : https://medium.com/@krishankantsinghal/logback-slf4j-log4j2-understanding-them-and-learn-how-to-use-d33deedd0c46 

Explains the differences in detail.

Quoting from there

**Slf4j**
&gt; So Basically Simple Logging Facade for Java serves as a simple facade or abstraction for various logging frameworks allowing the end user to plug in the desired logging framework at deployment time.

**log4j2**

&gt; Log4j,Logback and java.util.Logger are logging libraries which actually write the logs and have their own pros and cons. As industry standards are Log4j2 and logback

I would recommend going through the blog. It provides all the glory details how both are used with adapter.

I created a dataframe in spark with the following schema:

    root
     |-- user_id: long (nullable = false)
     |-- event_id: long (nullable = false)
     |-- invited: integer (nullable = false)
     |-- day_diff: long (nullable = true)
     |-- interested: integer (nullable = false)
     |-- event_owner: long (nullable = false)
     |-- friend_id: long (nullable = false)

And the data is shown below:

    +----------+----------+-------+--------+----------+-----------+---------+
    |   user_id|  event_id|invited|day_diff|interested|event_owner|friend_id|
    +----------+----------+-------+--------+----------+-----------+---------+
    |   4236494| 110357109|      0|      -1|         0|  937597069|     null|
    |  78065188| 498404626|      0|       0|         0| 2904922087|     null|
    | 282487230|2520855981|      0|      28|         0| 3749735525|     null|
    | 335269852|1641491432|      0|       2|         0| 1490350911|     null|
    | 437050836|1238456614|      0|       2|         0|  991277599|     null|
    | 447244169|2095085551|      0|      -1|         0| 1579858878|     null|
    | 516353916|1076364848|      0|       3|         1| 3597645735|     null|
    | 528218683|1151525474|      0|       1|         0| 3433080956|     null|
    | 531967718|3632072502|      0|       1|         0| 3863085861|     null|
    | 627948360|2823119321|      0|       0|         0| 4092665803|     null|
    | 811791433|3513954032|      0|       2|         0|  415464198|     null|
    | 830686203|  99027353|      0|       0|         0| 3549822604|     null|
    |1008893291|1115453150|      0|       2|         0| 2245155244|     null|
    |1239364869|2824096896|      0|       2|         1| 2579294650|     null|
    |1287950172|1076364848|      0|       0|         0| 3597645735|     null|
    |1345896548|2658555390|      0|       1|         0| 2025118823|     null|
    |1354205322|2564682277|      0|       3|         0| 2563033185|     null|
    |1408344828|1255629030|      0|      -1|         1|  804901063|     null|
    |1452633375|1334001859|      0|       4|         0| 1488588320|     null|
    |1625052108|3297535757|      0|       3|         0| 1972598895|     null|
    +----------+----------+-------+--------+----------+-----------+---------+

I want to filter out the rows have null values in the field of &quot;friend_id&quot;.

    scala&gt; val aaa = test.filter(&quot;friend_id is null&quot;)

    scala&gt; aaa.count
I got :res52: Long = 0 which is obvious not right. What is the right way to get it?

One more question, I want to replace the values in the friend_id field. I want to replace null with 0 and 1 for any other value except null. The code I can figure out is:

    val aaa = train_friend_join.select($&quot;user_id&quot;, $&quot;event_id&quot;, $&quot;invited&quot;, $&quot;day_diff&quot;, $&quot;interested&quot;, $&quot;event_owner&quot;, ($&quot;friend_id&quot; != null)?1:0)

This code also doesn&#39;t work. Can anyone tell me how can I fix it? Thanks


how to filter out a null value from spark dataframe

Need to know what&#39;s the difference between setup.py and setup.cfg. Both are used prominently in openstack projects

What&#39;s the difference between setup.py and setup.cfg in python projects

I am little bit confused by these three logger libraries. It seems like that they can do the similar thing in Java logging...

What is the difference between Log4j, SLF4J and Logback?

<p>I am little bit confused by these three logger libraries. It seems like that they can do the similar thing in Java logging...</p>


Guided by [Serving Web Content with Spring MVC](https://spring.io/guides/gs/serving-web-content/), I&#39;m creating a Spring Boot web application that I can run using both the embedded Tomcat instance as well as on a standalone Tomcat 8 server.

The application works as expected when executed as `java -jar adminpage.war` and I see the expected outcome when I visit `http://localhost:8080/table`. However, when I deploy to a Tomcat 8 server (by dropping `adminpage.war` into the `webapps` directory), I get a 404 error when I visit `https://myserver/adminpage/table`.

The `catelina.log` and `localhost.log` files contain nothing helpful on the Tomcat server.

Can anyone suggest where I&#39;ve made a misconfiguration? I&#39;ve not had the same problems in the past when deploying RESTful services with Spring Boot, but this is my first foray into a web application.

My application files:

`src/main/java/com/.../Application.java`

    @SpringBootApplication
    public class Application {
        public static void main(String[] args) {
            SpringApplication.run(Application.class, args);
        }
    
    }

`src/main/java/com/.../MainController.java`

    @Controller
    public class MainController {
    
        @RequestMapping(&quot;/table&quot;)
        public String greeting(Model model) {
            model.addAttribute(&quot;name&quot;, &quot;Fooballs&quot;);
            return &quot;table&quot;;
        }
    }

`src/main/resources/templates/table.html`

&lt;!-- language: lang-html --&gt;

	&lt;!DOCTYPE HTML&gt;
	&lt;html xmlns:th=&quot;http://www.thymeleaf.org&quot;&gt;
	&lt;head&gt;
	    &lt;meta http-equiv=&quot;Content-Type&quot; content=&quot;text/html; charset=UTF-8&quot; /&gt;
	&lt;/head&gt;
	&lt;body&gt;
	    &lt;p th:text=&quot;&#39;Hello, &#39; + ${name} + &#39;!&#39;&quot; /&gt;
	&lt;/body&gt;
	&lt;/html&gt;

`pom.xml`

&lt;!-- language: lang-xml --&gt;

    &lt;project
      xmlns=&quot;http://maven.apache.org/POM/4.0.0&quot;
      xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot;
      xsi:schemaLocation=&quot;http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd&quot;&gt;
      &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
      &lt;groupId&gt;com.foo&lt;/groupId&gt;
      &lt;artifactId&gt;adminpage&lt;/artifactId&gt;
      &lt;version&gt;1.0-SNAPSHOT&lt;/version&gt;
      &lt;packaging&gt;war&lt;/packaging&gt;
    
      &lt;parent&gt;
        &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
        &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
        &lt;version&gt;1.4.0.RELEASE&lt;/version&gt;
      &lt;/parent&gt;
    
      &lt;dependencies&gt;
        &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-web&lt;/artifactId&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-tomcat&lt;/artifactId&gt;
          &lt;scope&gt;provided&lt;/scope&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-thymeleaf&lt;/artifactId&gt;
        &lt;/dependency&gt;
        &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-devtools&lt;/artifactId&gt;
          &lt;optional&gt;true&lt;/optional&gt;
        &lt;/dependency&gt;
      &lt;/dependencies&gt;
    
      &lt;properties&gt;
        &lt;java.version&gt;1.8&lt;/java.version&gt;
        &lt;project.build.sourceEncoding&gt;UTF-8&lt;/project.build.sourceEncoding&gt;
      &lt;/properties&gt;
    
    
      &lt;build&gt;
        &lt;finalName&gt;adminpage&lt;/finalName&gt;
    
        &lt;plugins&gt;
          &lt;plugin&gt;
            &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
            &lt;artifactId&gt;spring-boot-maven-plugin&lt;/artifactId&gt;
          &lt;/plugin&gt;
        &lt;/plugins&gt;
      &lt;/build&gt;
    
    &lt;/project&gt;

Spring Boot application gives 404 when deployed to Tomcat but works with embedded server

In this code:
    
    if (value &gt;= x &amp;&amp; value &lt;= y) {

when `value &gt;= x` and `value &lt;= y` are as likely true as false with no particular pattern, _would using the `&amp;` operator be faster than using `&amp;&amp;`_?

Specifically, I am thinking about how `&amp;&amp;` lazily evaluates the right-hand-side expression (ie only if the LHS is true), which implies a conditional, whereas in Java `&amp;` in this context guarantees strict evaluation of both (boolean) sub-expressions. The value result is the same either way.

But whilst a `&gt;=` or `&lt;=` operator will use a simple comparison instruction, the `&amp;&amp;` must involve a branch, and _that branch is susceptible to branch prediction failure_ - as per this Very Famous Question: https://stackoverflow.com/questions/11227809/why-is-it-faster-to-process-a-sorted-array-than-an-unsorted-array

So, forcing the expression to have no lazy components will surely be more deterministic and not be vulnerable to prediction failure. Right?

Notes: 

  - obviously the answer to my question would be _No_ if the code looked like this: `if(value &gt;= x &amp;&amp; verySlowFunction())`. I am focusing on &quot;sufficiently simple&quot; RHS expressions.
  - there&#39;s a conditional branch in there anyway (the `if` statement). I can&#39;t quite prove to myself that that is irrelevant, and that alternative formulations might be better examples, like `boolean b = value &gt;= x &amp;&amp; value &lt;= y;`
  - this all falls into the world of horrendous micro-optimizations. Yeah, I know :-) ... interesting though?

**Update**
Just to explain why I&#39;m interested: I&#39;ve been staring at the systems that Martin Thompson has been writing about on his [Mechanical Sympathy blog][1], after he came and [did a talk][2] about Aeron. One of the key messages is that our hardware has all this magical stuff in it, and we software developers tragically fail to take advantage of it. Don&#39;t worry, I&#39;m not about to go s/&amp;&amp;/\&amp;/ on all my code :-) ... but there are a number of questions on this site on improving branch prediction by removing branches, and it occurred to me that the conditional boolean operators are _at the core_ of test conditions. 

Of course, @StephenC makes the fantastic point that bending your code into weird shapes can make it less easy for JITs to spot common optimizations - if not now, then in the future. And that the Very Famous Question mentioned above is special because it pushes the prediction complexity far beyond practical optimization. 

I&#39;m pretty much aware that in most (or _almost all_) situations, `&amp;&amp;` is the clearest, simplest, fastest, best thing to do - although I&#39;m very grateful to the people who have posted answers demonstrating this! I&#39;m really interested to see if there are actually any cases in anyone&#39;s experience where the answer to &quot;Can `&amp;` be faster?&quot; might be _Yes_...

**Update 2**: 
*(Addressing advice that the question is overly broad. I don&#39;t want to make major changes to this question because it might compromise some of the answers below, which are of exceptional quality!)* Perhaps an example in the wild is called for; this is from the [Guava LongMath][3] class (thanks hugely to @maaartinus for finding this):

    public static boolean isPowerOfTwo(long x) {
        return x &gt; 0 &amp; (x &amp; (x - 1)) == 0;
    }

See that first `&amp;`? And if you check the link, the *next* method is called `lessThanBranchFree(...)`, which hints that we are in branch-avoidance territory -  and Guava is really widely used: every cycle saved causes sea-levels to drop visibly.  So let&#39;s put the question this way: *is this use of `&amp;` (where `&amp;&amp;` would be more normal) a real optimization?*

  [1]: http://mechanical-sympathy.blogspot.co.uk/
  [2]: http://docklandsljc.uk/2015/09/aeron-next-generation-high-performance-messaging.html
  [3]: https://github.com/google/guava/blob/master/guava/src/com/google/common/math/LongMath.java#L97

In Java, can &amp; be faster than &amp;&amp;?

I seem to have a problem with performance of &quot;sbt test&quot; (which includes looking up localhost names/IP addresses) after upgrading to macOS Sierra. On a previous version of OS X it took about 40-50 seconds to finish. macOS Sierra times are much higher than that. Last run I did was around 15 minutes. Compile times are about the same as on &#39;El Capitan&#39;.

I&#39;m the only one from my team to try this new macOS so I can&#39;t tell if it&#39;s only happening on my mac or is it a universal issue.

My colleague had a similar issue on Ubuntu and it was related with random number generation slowing down the tests - https://stackoverflow.com/questions/27173833/slow-service-response-times-java-securerandom-dev-random

Unfortunately, that didn&#39;t work for me. Originally I tried that on JDK 8u54 and then tried updating to JDK 8u102 and that didn&#39;t help as well.


P.S. I&#39;m running Macbook Pro Mid-2015 2.8GHz i7, 16GB ram, 1TB SSD.


Jvm takes a long time to resolve ip-address for localhost

I&#39;m trying to write a program that works with Excel docs, but the HSSF format is too small for my requirements. I&#39;m attempting to move to XSSF, but I keep getting errors when trying to use it.

I managed to solve the first two by adding xmlbeans-2.3.0.jar and dom4j-1.6.jar to my program, but now this error is coming up, which doesn&#39;t seem to be resolved by adding the Apache commons jar available on the Apache website.

The error is as follows:

    Exception in thread &quot;main&quot; java.lang.NoClassDefFoundError: org/apache/commons/collections4/ListValuedMap
    	at hot.memes.ExcelCreator.main(ExcelCreator.java:66)
    Caused by: java.lang.ClassNotFoundException: org.apache.commons.collections4.ListValuedMap
    	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    	... 1 more


Apache POI error loading XSSFWorkbook class

To my knowledge, Dagger does generate code, while Guice and Spring rely on runtime processing, thus Dagger works faster, but requires more work on programmer side. Because of performance edge it&#39;s good for mobile (Android) development.

However, when we are left with Guice and Spring, the latter has lots of integrations. What&#39;s the point of developing/using Guice, if we can use Spring Framework (that does basically same thing, but offers ex. easier database access)?

Isn&#39;t Google trying to reinvent wheel by creating their own DI tool, instead of using (and possibly contributing to) Spring Framework?

I am looking for decision tree, that guides through choosing DI tool.

Why use/develop Guice, when You have Spring and Dagger?

I&#39;m trying to do a test run of the `logging` module&#39;s `RotatingFileHandler` as follows:

    import logging
    from logging.handlers import RotatingFileHandler
    
    # logging.basicConfig(filename=&quot;example.log&quot;, level=logging.DEBUG)
    
    logger = logging.getLogger(&#39;my_logger&#39;)
    handler = RotatingFileHandler(&quot;my_log.log&quot;, maxBytes=2000, backupCount=10)
    logger.addHandler(handler)
    
    for _ in range(10000):
        logger.debug(&quot;Hello, world!&quot;)

However, with `logging.basicConfig` line commented out, the resulting `my_log.log` file contains no data:

[![enter image description here][1]][1]

If I comment in the line with `logging.basicConfig(filename=&quot;example.log&quot;, level=logging.DEBUG)`, I get the expected `my_log.log` files with numbered suffixes. However, there is also the `example.log` which is a (relatively) large file:

[![enter image description here][2]][2]

How can I set up the logging so that it only generates the `my_log.log` files, and not the large `example.log` file?


  [1]: https://i.stack.imgur.com/Q3CoP.png
  [2]: https://i.stack.imgur.com/J77C7.png

How to use Python&#39;s RotatingFileHandler

I&#39;m super new to React and I&#39;m trying to get it set up for Meteor and piecing stuff together from other sources too. One of these other sources set up console logging for the app, but I&#39;m going the ES6/JSX way so just using their code wouldn&#39;t work for me (or it doesn&#39;t seem like it does).

Some code I found for logging is

    import Logger from &#39;simple-console-logger&#39;;
    Logger.configure({level: &#39;debug&#39;});

but I&#39;m seeing this error
[![cannot find module &#39;./dumy&#39;][1]][1]

I also tried using `react-logger` and `react-console-logger` to no avail. Here&#39;s my code for the latter, which I believe should work.

    import {Logger, ConsoleLogger} from &#39;react-console-logger&#39;;
    const myLogger = new Logger();
    export default class App extends Component {
        render() {
            myLogger.info(&#39;something witty&#39;);
        }
    }

However, `myLogger.info(&#39;...&#39;)` is making a call to `node_modules/react-console-logger/lib/Logger.js` which has it defined as

[![picture of code since copy-paste doesn&#39;t work][2]][2]

And `this.logger` is undefined, although I see it be defined above?

Does anyone know what I&#39;m doing wrong? It looks to me like the library has it wrong, but maybe it has something to do with me using JSX files instead of js? 


  [1]: https://i.stack.imgur.com/CfRJo.png
  [2]: https://i.stack.imgur.com/6XFZ0.png

Console logging for react?

I&#39;m trying to verify that my source and target paths are properly setup when I execute a deploy command.

See the example below:&lt;br/&gt;
(copied from: http://eppz.eu/blog/unity-android-plugin-tutorial-2/)

```groovy
android.libraryVariants.all { variant -&gt;
	// Task names.
	String variantName = &quot;${variant.name.capitalize()}&quot;; // Like &#39;Debug&#39;
	String deployTaskGroup = &quot;plugin&quot;;
	String deployTaskName = &quot;deploy${variantName}PluginArchive&quot;; // Like &#39;deployDebugPluginArchive&#39;
	String dependencyTaskName = &quot;assemble${variantName}&quot;; // Like &#39;assembleDebug&#39;
	// Source.
	String sourceAARFolder = &quot;${buildDir.getPath()}/outputs/aar/&quot;;
	String sourceAARName = &quot;${project.name}-${variant.name}.aar&quot;;
	// Target.
	String targetAssetFolder = &quot;Assets/Plugins/My Plugin&quot;;
	String targetAARFolder = &quot;${rootDir.getPath()}/../../${targetAssetFolder}&quot;; // Navigate into &#39;Assets&#39;
	String targetAARName = &quot;My Plugin Android.aar&quot;; // The form you ship your plugin

    String targetProjDir = System.env.UNITY_PROJECT; // &lt;-- Need to confirm this line!
    //Log.i(targetProjDir); //??????????? something like this?

	// Create task.
	task(deployTaskName, dependsOn: dependencyTaskName, type: Copy) {
		from(sourceAARFolder)
		into(targetAARFolder)
		include(sourceAARName)
		rename(sourceAARName, targetAARName)
	}.group = deployTaskGroup;
}
```

Is there any way to display the above `targetProjDir` string variable to some sort of console, or the Event Log in Android Studio (assuming that is it&#39;s console&#39;s name)?


In Gradle, how to print out a message in the console / Event Log?

I want to redirect all the logs of my docker container to single log file to analyse them. I tried 

    docker logs container &gt; /tmp/stdout.log 2&gt;/tmp/stderr.log

 but this gives log in two different file. I already tried 

    docker logs container &gt; /tmp/stdout.log

 but it did not work.

How to redirect docker container logs to a single file?

I am not able to decide whether to use slf4j or not with log4j2. Based on online posts, does not look like it will have any performance hit but is it really required. 

Also these points rule in favor of log4j2:

- SLF4J forces your application to log Strings. The Log4j 2 API supports logging any CharSequence if you want to log text, but also supports logging any Object as is.
- The Log4j 2 API offers support for logging Message objects, Java 8 lambda expressions and garbage-free logging (it avoids creating vararg arrays and avoids creating Strings when logging CharSequence objects).

Is it worth to use slf4j with log4j2

With regard to the [Log4j][1] [JNDI][2] remote code execution vulnerability that has been identified [CVE-2021-44228][3]  - (also see references) - I wondered if [Log4j-v1.2][4] is also impacted, but the closest I got from source code review is the [JMS-Appender][5].

The question is, while the posts on the Internet indicate that Log4j 1.2 is also vulnerable, I am not able to find the relevant source code for it.

Am I missing something that others have identified?

Log4j 1.2 appears to have a vulnerability in the [socket-server][6] class, but my understanding is that it needs to be enabled in the first place for it to be applicable and hence is not a passive threat unlike the JNDI-lookup vulnerability which the one identified appears to be.

***Is my understanding - that Log4j v1.2 - is not vulnerable to the jndi-remote-code execution bug correct?***

### References

 * *[Apache Log4j Security Vulnerabilities][7]*

 * *[Zero-day in ubiquitous Log4j tool poses a grave threat to the Internet][8]*

 * *[Worst Apache Log4j RCE Zero day Dropped on Internet][9]*

 * *[‘Log4Shell’ vulnerability poses critical threat to applications using ‘ubiquitous’ Java logging package Apache Log4j][10]*

This [blog post from Cloudflare][11] also indicates the same point as from [AKX][12]....that it was introduced from Log4j 2!

**Update #1** - A fork of the (now-retired) apache-log4j-1.2.x with patch fixes for few vulnerabilities identified in the older library is now available (from the original log4j author). The site is https://reload4j.qos.ch/. As of 21-Jan-2022 version 1.2.18.2 has been released. Vulnerabilities addressed to date include those pertaining to [JMSAppender][13], [SocketServer][14] and [Chainsaw][15] vulnerabilities. Note that I am simply relaying this information. Have not verified the fixes from my end. Please refer the link for additional details.


  [1]: https://en.wikipedia.org/wiki/Log4j
  [2]: https://en.wikipedia.org/wiki/Java_Naming_and_Directory_Interface
  [3]: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44228
  [4]: https://dlcdn.apache.org/logging/log4j/1.2.17/log4j-1.2.17.zip
  [5]: https://github.com/kikonen/log4j-share/blob/master/src/main/java/org/apache/log4j/net/JMSAppender.java
  [6]: https://github.com/kikonen/log4j-share/blob/master/src/main/java/org/apache/log4j/net/SocketServer.java
  [7]: https://logging.apache.org/log4j/2.x/security.html
  [8]: https://arstechnica.com/information-technology/2021/12/minecraft-and-other-apps-face-serious-threat-from-new-code-execution-bug/
  [9]: https://www.cyberkendra.com/2021/12/worst-log4j-rce-zeroday-dropped-on.html
  [10]: https://portswigger.net/daily-swig/log4shell-vulnerability-poses-critical-threat-to-applications-using-ubiquitous-java-logging-package-apache-log4j
  [11]: https://blog.cloudflare.com/inside-the-log4j2-vulnerability-cve-2021-44228/
  [12]: https://stackoverflow.com/users/51685/akx
  [13]: https://cve.report/CVE-2021-4104
  [14]: https://cve.report/CVE-2019-17571
  [15]: https://cve.report/CVE-2022-23307

Content Type	Original Author	Original Content on Stackoverflow
Question	Ev3rlasting	View Question on Stackoverflow
Solution 1 - Java	Andreas	View Answer on Stackoverflow
Solution 2 - Java	Avishek Bhattacharya	View Answer on Stackoverflow

What is the difference between Log4j, SLF4J and Logback?

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

What's the difference between setup.py and setup.cfg in python projects

how to filter out a null value from spark dataframe

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