I have searched enough for the below question but could not find the appropriate answer. I would be glad if you can provide me a link if the question already exists.
I am new to Maven and I have created a Maven based application integrated with Hibernate.
Question:
I have a log4j.properties file in "src/java/resources" I have created a Logger instance in one of my classes and tried to print logs however the logs do not get printed on to the console.
Note: I have given the stdout as logs output location.
src/java/resources/ sounds suspicious. The correct location for classpath resources is src/main/resources/. Put the log4j.properties there.
Additionally, it depends on the version you're using. log4j.properties is no longer supported in newer version. In case you use log4j 2, migrate to log4j2.xml.
Related
I am trying to do a log4j migration for a legacy application. I made the changes to the configuration files and tested it locally with Tomcat, where the logs were displayed correctly. However when I deploy on WAS, the logging stops.
I checked a lot of pages about the necessary dependencies and the possible problems, but now I feel I'm stuck. Here is what I already tried:
Added the log4j jars manually to the lib/ext directory in WAS (together with commons-logging, I read an article where it helped, although all these jar-s were already present in the ear)
Double checked, that the configuration file is on the classpath and that it's syntax is correct
Added logj42-web dependency
Added the necessary filters in web.xml (Spring version is 3.8, so also the config listener with the config name context-param)
Checked classloader in WAS - it's parent first
Am I missing something?
Any ideas are appreciated. Thank you in advance!
WAS includes its own commons-logging API (that does not utilize Log4j), so bringing your own logger requires a bit of extra class-loader-related config. Typically, that would go something like this:
Put your commons-logging and log4j jars, along with your logging properties files, in some directory (not WAS_HOME/lib/ext) readable by the user running the server.
Create a shared library on the server, with that directory as its class path, and select the "use an isolated class loader" option. Associate that shared library with your application or web module.
Ideally, that should be it. Isolated shared libraries search themselves before delegating to the server's loaders, so your application will "see" the commons-logging/log4j classes in the shared library instead of in the server, and likewise, it should pick up the configuration files from that directory instead of the ones found in the server.
You can also accomplish this same basic thing by leaving all the logging stuff in your WAR or EAR and setting its class loader to parent-last (which causes the class loader to search locally before delegating to the server-level loaders), but that is a bit riskier configuration - if your application includes APIs that are also provided by the server, parent-last class loading increases the possibility of ClassCastExceptions or LinkageErrors.
I am using log4j2 in my spring boot application. This works in all respects re: excluding slf4j, including log4j2, etc.
But when the application deploys I need to customize the file for each target host. I have created an ansible role that does this. Ultimately I end up with a log4j2.xml file deployed in another directory e.g. /prod/produsrX/data/log4j2.xml.
I am using the spring-boot-maven-plugin "repackage" goal to generate an executable jar file. It doesn't seem like that should matter but it is a data point in the problem.
This was supposed to be the easiest part of the project. Always before I have just been able to set -Dlog4j.configurationFile - advice which is echoed on about 3,000 web pages and DOES NOT WORK in Spring Boot 2.1.3.
The most useful info I've found is this question. It talks about using -Dlogging.config because logging must be initialized before other properties are read. Unfortunately that didn't help either.
I did find one example that suggested specifying the above directory in a -classpath parameter to java. But that didn't help either.
Does anyone know how to get a spring boot application to read the log4j2.xml file?
The property actually has to be put into the application context (e.g. application.yml). Using a -D property does not work!
logging:
config: /prod/produsrX/data/log4j2.xml #fully qualified name to your log4j.xml
Never worked with log4j before, that's why I may ask some stupid questions.
I got a multi-module Maven Web Application that runs on Glassfish 3.1.
Every module is more or less independent.
Well, I set up the log4j configurations (log4j.properties), put it in the Dist "module" config folder. Also, every pom.xml of every module has a log4j dependency. Added the classpaths. Also, added in the domain.xml the jvm option, referencing the log4j.property:
<jvm-options>-Dlog4j.configuration=file:///${com.sun.aas.instanceRoot}/log4j.properties</jvm-options>
In the Glassfish Admin panel, i added Configuration option referencing to the log4j.properties file (Configuration -> severf-config -> JVM General Settings -> JVM Options).
-Dlog4j.configuration=file:///${com.sun.aas.instanceRoot}/log4j.properties
I found This stuff out reading a lot on the Internet about log4j.
So, now my problem is that when I start the Maven Build, the build executes the Unit Test, and the framework works just fine, ut it doesn't log any activity from the application. What could it be?
Does every module needs its own log4j.property (I guess not, because it's logging already entries from methods called from the unit test from modules that don't have the log4j.propertie).
Is it possible that the log4j has to bi initialized before/during the start of the application?
Again, it logs unit test and maven build, but not during runtime, that's what I don't get. Am I missing something?
The solution was to put the log4j.properties file into the persist Maven module (src/main/resources).
Now, it logs the activities..
I'm working on a project that uses two maven projects (named core and webapp); core is built with JAR packaging and used for two different purposes: as a stand-alone app (essentially an executable JAR), and also embedded into webapp.
For its purpose as a stand-alone app, core needs to have its own logback configuration (a logback.xml file) that needs to be included on the classpath. Normal Maven convention would have me put it in src/main/resources/logback.xml. That works fine, but causes a problem when the core JAR is included in webapp. webapp needs to have its own logback configuration, but the container (tc Server or Jetty) is picking up the one from core.jar first.
I realize that logback can be told about a custom config location via a system property (-D on the command line) but that's not viable in a app container like Tomcat or Jetty.
I've read some other people asking about this situation, but none of the solutions I've seen sits well with me. One solution involved setting up a context listener that runs early in the webapp initialization and explicitly configures logback based on a <context-param>. That's a bit brutish in my opinion, and probably a hard sell to my fellow dev team when log4j "just works" in this situation.
I'm far from a Maven expert, so I'm hoping there is some elegant way to get Maven to help me here. Or perhaps some logback extension or add-on that makes it more web-app friendly. Or even a clever idea that I haven't thought of.
There are a number of possible solutions, but the easiest is to put the file in its own module and mark the dependency as provided. The, conspire to have it on the classpath when running the standalone version of the app.
The solution that we ended up using was to leave only the common "non-app" pieces (code and configuration) in core and then extract the other "app" pieces into a new module (batch-app).
The logging configuration only lives in the 2 app projects (webapp and batch-app) that depend on core. core has a logback-test.xml configuration in it, but that's excluded from the JAR that maven builds (since it's in the src/test/resources folder).
I'm confused as to how the errors are logged without me implicitly catching them and logging out the error. All that I've done is put a log4j.xml file in my project defining appenders and now the logs catch and log everything from the frameworks.
If I say, try to query in Hibernate and the query fails, or I try to open a file that doesn't exist, or I get a null pointer exception, if the log4j.xml file defines a log file, and the error level is set correctly, then the error will be captured there?
How does my spring web app capture errors that I didn't catch and log? Is this a result of apache commons logging?
Or is this some magic that log4j knows how to deal with - catch stream to the console etc?
Any info appreciated.
From spring official documentation:
The nice thing about commons-logging is that you don't need anything else to make your application work. It has a runtime discovery algorithm that looks for other logging frameworks in well known places on the classpath and uses one that it thinks is appropriate (or you can tell it which one if you need to). If nothing else is available you get pretty nice looking logs just from the JDK (java.util.logging or JUL for short). You should find that your Spring application works and logs happily to the console out of the box in most situations, and that's important.
To make Log4j work with the default JCL dependency (commons-logging)
all you need to do is put Log4j on the classpath, and provide it with
a configuration file (log4j.properties or log4j.xml in the root of the
classpath).
Take a look for a complete explanation: http://static.springsource.org/spring/docs/3.0.x/reference/overview.html#d0e743