    log4j-over-slf4j

Use this if your code or some libraries you are using uses Log4j directly, but you want to use a **different SLF4J binding than Log4j**. It will route the Log4j API calls to SLF4J to the binding you choose. You need to remove the Log4j library from your classpath and replace it with this dependency.

    slf4j-log4j12

Use this if you **want to use the Log4j 1.2 binding for SLF4J**.

You shouldn&#39;t use both of these libraries [at the same time][2].

Please note also that [Log4j 2 has been released][1].


  [1]: http://logging.apache.org/log4j/2.x/log4j-slf4j-impl/index.html
  [2]: http://www.slf4j.org/legacy.html#log4j-over-slf4j

I have a structure as follows:

    struct app_data
    {
        int port;
        int ib_port;
        unsigned size;
        int tx_depth;
        int sockfd;
        char *servername;
        struct ib_connection local_connection;
        struct ib_connection *remote_connection;
        struct ibv_device *ib_dev;
    
    };

When I try to initialize it thus:

    struct app_data data =
    {
        .port = 18515,
        .ib_port = 1,
        .size = 65536,
        .tx_depth = 100,
        .sockfd = -1,
        .servername = NULL,
        .remote_connection = NULL,
        .ib_dev = NULL
    };

I get this error:

    sorry, unimplemented: non-trivial designated initializers not supported

I think it wants the order of initialization exactly as it is declared, and `local_connection` is missing. I don&#39;t need to initialize it though, and setting it to NULL doesn&#39;t work.

If I change it to this for g++, still get the same error:

    struct app_data data =
    {
        port : 18515,
        ib_port : 1,
        size : 65536,
        tx_depth : 100,
        sockfd : -1,
        servername : NULL,
        remote_connection : NULL,
        ib_dev : NULL
    };


non-trivial designated initializers not supported

What is the difference between these 2 settings?

    set clipboard=unnamed
    set clipboard=unnamedplus

Which one should I use in order to have multi-platform .vimrc?

What is difference between Vim&#39;s clipboard &quot;unnamed&quot; and &quot;unnamedplus&quot; settings?

What&#39;s the difference between slf4j-log4j12 and [log4j-over-slf4j][1] and when should each be used?

&lt;!-- language: lang-xml --&gt;

    &lt;dependency&gt;
    	&lt;groupId&gt;org.slf4j&lt;/groupId&gt;
    	&lt;artifactId&gt;slf4j-log4j12&lt;/artifactId&gt;
    	&lt;version&gt;1.7.12&lt;/version&gt;
    &lt;/dependency&gt;
    &lt;dependency&gt;
    	&lt;groupId&gt;org.slf4j&lt;/groupId&gt;
    	&lt;artifactId&gt;log4j-over-slf4j&lt;/artifactId&gt;
    	&lt;version&gt;1.7.12&lt;/version&gt;
    &lt;/dependency&gt;


  [1]: https://www.slf4j.org/legacy.html#log4j-over-slf4j

Difference between slf4j-log4j12 and log4j-over-slf4j

What's the difference between slf4j-log4j12 and <a href="https://www.slf4j.org/legacy.html#log4j-over-slf4j" target="_blank" rel="noopener noreferrer">log4j-over-slf4j</a> and when should each be used?

<pre><code class="hljs language-php-template">&#x3C;dependency>
	&#x3C;groupId>org.slf4j&#x3C;/groupId>
	&#x3C;artifactId>slf4j-log4j12&#x3C;/artifactId>
	&#x3C;version>1.7.12&#x3C;/version>
&#x3C;/dependency>
&#x3C;dependency>
	&#x3C;groupId>org.slf4j&#x3C;/groupId>
	&#x3C;artifactId>log4j-over-slf4j&#x3C;/artifactId>
	&#x3C;version>1.7.12&#x3C;/version>
&#x3C;/dependency>
</code></pre>

I&#39;m wondering, if there is a generic way to fill a map with properties you just know the prefix.

Assuming there are a bunch of properties like

    namespace.prop1=value1
    namespace.prop2=value2
    namespace.iDontKnowThisNameAtCompileTime=anothervalue

I&#39;d like to have a generic way to fill this property inside a map, something like

    @Component
    @ConfigurationProperties(&quot;namespace&quot;)
    public class MyGenericProps {
        private Map&lt;String, String&gt; propmap = new HashMap&lt;String, String&gt;();
        
        // setter and getter for propmap omitted

        public Set&lt;String&gt; returnAllKeys() {
            return propmap.keySet();
        }
    }

Or is there another convenient way to collect all properties with a certain prefix, instead of iterating over all PropertySources in the environment?

Thanks
Hansjoerg

Using ConfigurationProperties to fill Map in generic way

**Question 1:**

Why does the following code compile without having a return statement?
		
	public int a() {
		while(true);
	}

Notice: If I add return after the while then I get an `Unreachable Code Error`.

**Question 2:** 

On the other hand, why does the following code compile,

	public int a() {
		while(0 == 0);
	}

even though the following does not.

	public int a(int b) {
		while(b == b);
	}

Java method with return type compiles without return statement

I have the following descriptions for some Maven entries in Project Structure:

![enter image description here][1]

Javadoc file is really absent in filesystem. Simultaneously, it is present in central repository. Why it was not downloaded and how to download it by force?

**UPDATE**

These options are ON already:

![enter image description here][2]

Have tried to recompile, close/open etc after setting them...


  [1]: http://i.stack.imgur.com/0U10y.png
  [2]: http://i.stack.imgur.com/WblxR.png

How to force IntelliJ to download javadocs with Maven?

What is the right way to add HttpRequest interceptors in spring boot application? What I want to do is log requests and responses for every http request.

Spring boot documentation does not cover this topic at all. (http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/)

I found some web samples on how to do the same with older versions of spring, but those work with applicationcontext.xml. Please help.

Spring Boot Adding Http Request Interceptors

Please read the question carefully before marking this as duplicate. 

Below is the snippet of the pseudo code. 
My question is- Does the below code not defeat the very notion of parallel asynchronous processing? 

The reason I ask this is because in the below code the main thread would submit a task to be executed in a different thread. After submitting the task in the queue, it blocks on Future.get() method for the task to return the value. I would rather have the task executed in the main thread rather than submitting to a different thread and waiting for the results. What is that I gained by executing the task in a new thread? 

I am aware that you could wait for a limited time etc, but then what if I really care about the result? The problem gets worse if there are multiple tasks to be executed. It seems to me that we are just doing the work synchronously. I am aware of the Guava library which provides a non blocking listener interface. But I am interested to know if my understanding is correct for the Future.get() API. If it is correct, why is the Future.get() designed to block thereby defeating the whole process of parallel processing?

Note - For the record, I use JAVA 6


    public static void main(String[] args){
    
    private ExectorService executorService = ...
    
    Future future = executorService.submit(new Callable(){
        public Object call() throws Exception {
            System.out.println(&quot;Asynchronous Callable&quot;);
            return &quot;Callable Result&quot;;
        }
    });
    
    System.out.println(&quot;future.get() = &quot; + future.get());
    }

Method call to Future.get() blocks. Is that really desirable?

As we all know, at least four or five Log4j JAR files end up being in the classpath. How can I tell which version I am using?





How can I find out what version of Log4J I am using?

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?

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

Log4j vulnerability - Is Log4j 1.2.17 vulnerable (was unable to find any JNDI code in source)?

I use Spring Boot and want it to write log output to a file.

According to the docs, this is simply done by setting

    logging.file=filename.log

While the console output works fine, `filename.log` is not created. Also, if I create the file manually, nothing is written to it. What do I miss?

Content Type	Original Author	Original Content on Stackoverflow
Question	Kumar Sambhav	View Question on Stackoverflow
Solution 1 - Java	Puce	View Answer on Stackoverflow

Difference between slf4j-log4j12 and log4j-over-slf4j

Java Problem Overview

Java Solutions

Solution 1 - Java

What is difference between Vim's clipboard "unnamed" and "unnamedplus" settings?

non-trivial designated initializers not supported

Attributions