I am quite confused about maven compiler plugin and what it does. I have a project that has several modules. In my top pom.xml I have a section
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.5.1</version>
<inherited>true</inherited>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
My understanding is this specifies the JDK compiler version used to compile the code, and this section get inherited by all the modules. What I don't get is in my IntelliJ IDEA I can still specify project JDK in the settings and it seems like that setting overrides this. When I run maven install in the IDE I can confirm that it is using javac from JDK 8 to compile. So what does this section do exactly?
You are correct; maven-compiler settings should be inherited by child modules.
I don't know about IntelliJ, but I can tell you that Eclipse picks&chooses whatever it wants from maven config, and for all the rest it uses its own settings.
Therefore, I'd expect IntelliJ may do something similar?
The simplest way to test this is to run a mvn clean install via command line, and see which "wins". If you get artifact compiled with 1.8 then it means you're missing something in Maven config which causes those settings not to propagate to children. If you get artifact compiled with 1.7 then it is IntelliJ who does it and not maven-compiler-plugin.
Related
I'm attempting to upgrade a 15 year old Maven multimodule project to Java 11, and the module system that was introduced in Java 9. Since the project is built using Maven, all dependencies are pretty clear. First I want to do this using the automatic module names, in order not to also introduce upgraded artifacts (if not absolutely required).
Eclipse is pretty helpful in this process, autocompleting the automatic module names in the module-info.java. For example:
requires dom4j;
But if I compile with Maven, I get errors about that it cannot find the modules Eclipse just autocompleted in there.
module-info.java:[29,18] module not found: dom4j
I am using Maven's compiler plugin 3.7.0 (3.8.0 gives a NullPointerException as per https://jira.apache.org/jira/browse/MCOMPILER-355) I suspect Maven is setting the jars up on the classpath instead of on the modulepath, but the compiler's plugin debug output does not log that.
How can I make Maven correctly handle those modules?
I was running into the same issue. Adding
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
</plugin>
</plugins>
</build>
to my pom solved the problem for me...
Maven version 3.9.0 seems to be buggy and will not find the module although the dependency is using an Automatic-Module-Name. Downgrading to version 3.8.1 helps.
I have an interesting problem in a project where all of the technologies mentioned in the title are used. I've been able to track it down up to the diagnosis (the test classpath prepared by Surefire), but I don't understand whether it can be fixed and how. It's not a showstopper, indeed it's a minor issue for me, but I'd like to solve it anyway.
First a rough description.
The problem is related to executing tests in a specific module of the project, and only in a specific way.
Everything works (tests pass) when I run from the master pom level:
cd ${projHome}
mvn install
Everything works (tests pass) when I run:
cd ${projHome}/modules/CoreImplementation/
mvn test
That means that I can build and test with no problems, the same for my Jenkins, and NetBeans can run tests from the IDE when I need them.
But that module fails testing when I run from the master pom level:
cd ${projHome}
mvn test
with this error:
java.lang.NoSuchMethodError: it.tidalwave.northernwind.profiling.RequestProfilerAspect.aspectOf()Lit/tidalwave/northernwind/profiling/RequestProfilerAspect;
at it.tidalwave.northernwind.frontend.ui.spi.DefaultSiteViewController.processRequest(DefaultSiteViewController.java:82) ~[classes/:na]
at it.tidalwave.northernwind.frontend.ui.spi.DefaultSiteViewControllerTest.must_call_some_RequestProcessors_when_one_breaks(DefaultSiteViewControllerTest.java:161) ~[test-classes/:na]
Running mvn test as a second pass (after a mvn install -DskipTests) happens to be the way Drone.io and Travis do their job. While I could change their configuration, I'd like to stay with the standard configuration and fix the problem if possible.
The diagnosis in short and my question.
Now, the question in short (details are further below). I was able to track down the problem to different ways in which Surefire prepares the classpath to execute the tests.
When I run mvn install the classpath is:
${repo}/org/apache/maven/surefire/surefire-booter/2.16/surefire-booter-2.16.jar
${repo}/org/apache/maven/surefire/surefire-api/2.16/surefire-api-2.16.jar
${projHome}/modules/CoreImplementation/target/test-classes
${projHome}/modules/CoreImplementation/target/classes
${projHome}/modules/Core/target/it-tidalwave-northernwind-core-1.1-ALPHA-37-SNAPSHOT.952b0c8bdc77.jar
${repo}/it/tidalwave/thesefoolishthings/it-tidalwave-role/3.0-ALPHA-1/it-tidalwave-role-3.0-ALPHA-1.jar
${projHome}/modules/Profiling/target/it-tidalwave-northernwind-core-profiling-1.1-ALPHA-37-SNAPSHOT.952b0c8bdc77.jar
${repo}/org/apache/commons/commons-math3/3.0/commons-math3-3.0.jar
…
When I run mvn test (from the project home) the classpath is:
${repo}/org/apache/maven/surefire/surefire-booter/2.16/surefire-booter-2.16.jar
${repo}/org/apache/maven/surefire/surefire-api/2.16/surefire-api-2.16.jar
${projHome}/modules/CoreImplementation/target/test-classes
${projHome}/modules/CoreImplementation/target/classes
${projHome}/modules/Core/target/unwoven-classes
${repo}/it/tidalwave/thesefoolishthings/it-tidalwave-role/3.0-ALPHA-1/it-tidalwave-role-3.0-ALPHA-1.jar
${projHome}/modules/Profiling/target/unwoven-classes
${repo}/org/apache/commons/commons-math3/3.0/commons-math3-3.0.jar
…
The different portions are the indented ones. In the former case, SureFire uses the classes directory (forget for a moment that in my case they are named unwoven-classes) only for the module under test, and the installed jar files for every dependency. In the latter case, it seems to be using classes for all dependencies in the reactor.
The reason for which this difference in the classpaths gives me troubles is explained below in the "Gory details" section. In short, that unwoven means that they contain bytecode not augmented by AspectJ, hence the methods that can't be found at runtime.
I'm running with SureFire 2.16, but I've also tried the latest 2.19 with no changes. Being able to force SureFire to always use jar files for dependencies would fix my problems. If you have the answer, you can stop reading my post here.
Gory details (just for curiosity).
The faulty module artifactId is it-tidalwave-northernwind-core-default and it depends on aspects available in it-tidalwave-northernwind-core-profiling - that's where the offending RequestProfilerAspect is. The aspect library dependency is both in the regular dependencies of the faulty module and in the configuration of the aspectj plugin:
<dependency>
<groupId>it.tidalwave.northernwind</groupId>
<artifactId>it-tidalwave-northernwind-core-profiling</artifactId>
</dependency>
...
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>aspectj-maven-plugin</artifactId>
<configuration>
<aspectLibraries combine.children="append">
<dependency>
<groupId>it.tidalwave.northernwind</groupId>
<artifactId>it-tidalwave-northernwind-core-profiling</artifactId>
</dependency>
</aspectLibraries>
</configuration>
</plugin>
</plugins>
</build>
AspectJ integration is by means of the following profile in a Super POM, which is activated in the build, whose relevant part is:
<profile>
<id>it.tidalwave-aspectj-springaop-v1</id>
...
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<executions>
<execution>
<id>default-compile</id>
<phase>compile</phase>
<configuration>
<outputDirectory>target/unwoven-classes</outputDirectory>
</configuration>
</execution>
<execution>
<id>default-testCompile</id>
<phase>test-compile</phase>
<configuration>
<outputDirectory>target/unwoven-test-classes</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
...
The aspectj plugin is configured in the profile to statically weave binaries in the unwoven-test-classes directories. The reason for this approach is that it's the only feasible solution AFAIK to have both Lombok and AspectJ work together.
Now, back to the two classpaths described above: the fact that SureFire is using unwoven-classes means that it's pointing to bytecode that has not been augmented with AspectJ methods, hence the error.
References
The project is a FLOSS one and can be found at
https://bitbucket.org/tidalwave/northernwind-src
or
https://github.com/tidalwave-it/northernwind-src
A changeset where the problem can be reproduced is f98e9a89ac70138c1b6bd0d4570a22d59ed71be6. JDK 1.8.0 is required to build the project (even though it doesn't use Java 8 code yet).
The SuperPOM can be found here:
https://bitbucket.org/tidalwave/thesefoolishthings-superpom-src
When I run "mvn clean tomcat:run" (without specifying any tomcat version) command from command prompt for running my web application, it download tomcat 6.0.29 version dependency as shown below:
org/apache/tomcat/juli/6.0.29/juli-6.0.29.pom
org/apache/tomcat/annotations-api/6.0.29/annotations-api-6.0.29.pom
org/apache/tomcat/catalina-ha/6.0.29/catalina-ha-6.0.29.pom
org/apache/tomcat/coyote/6.0.29/coyote-6.0.29.pom
org/apache/tomcat/tribes/6.0.29/tribes-6.0.29.pom
org/apache/tomcat/jasper-el/6.0.29/jasper-el-6.0.29.pom
org/apache/tomcat/dbcp/6.0.29/dbcp-6.0.29.pom
pom.xml file of the application does not contain any tomcat version it require to run
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.0.2</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
<finalName>esa</finalName>
</build>
So my query is how does it decide to download particular this tomcat version dependency.
Probably the default settings of the tomcat plugin you run.
Try running mvn tomcat:help -Ddetails to see what version of the plugin you use, and how it can be configured.
I think it is an earlier version of the plugin, and you can now use explicit versions, such as
mvn org.apache.tomcat.maven:tomcat6-maven-plugin:2.0:run
mvn org.apache.tomcat.maven:tomcat7-maven-plugin:2.0:run
(or the shorter form)
Seems, you are running the tomcat-maven-plugin from codehaus, whihc has tomcat 6.0.29 built-in. (Seems there was no activity since 2010.)
You should try the tomcat7 plugin from apache.
Regards
Tibor
In command line for maven use --debug option to get explanation of build process. For our case output looks like:
...[DEBUG] Resolving plugin prefix tomcat from [org.apache.maven.plugins, org.codehaus.mojo]
...
[DEBUG] Resolved plugin version for org.codehaus.mojo:tomcat-maven-plugin to 1.1 from repository central (http://repo.maven.apache.org/maven2, releases)...
Actually to explain why we've got tomcat v1.1 without specifying anything about tomcat, remember that maven build process has been customized with build plugins. And each build plugins has own build plugins. So it is enough to examine effective pom file to get clear understanding that almost empty initial pom.xml has quite big effective pom.xml.
To overcome issue just use explicit version of the tomcat plugin.
In project pom.xml is it required to include both maven-release-plugin and maven-compiler-plugin? The reason I want the release plugin is because I want to release the project at the end of a sprint/release. I understand that the compiler plugin will compile the source code, however I am not sure if the release plugin will also compile the source code, apart from updating the pom and checking out/in to scm.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-release-plugin</artifactId>
<version>2.2.2</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
Any help with this is much appreciated.
If unspecified, Maven will know what to do when it needs to compile the code. However, in order to be able to control things like source and target versions, you will need to have a declaration of the maven-compiler-plugin.
It is generally good practice, to explicitly define the plugins you are using, along with their configurations and above all their versions, so that you have a guarantee of what was working.
What the Maven Release Plugin does is described here.
Your question is about the bullet "Run the project tests against the modified POMs to confirm everything is in working order". There is not that much magic here. What happens is that the maven-release-plugin will start a new Maven session. It will execute "mvn verify" in the same folder where you ran "mvn release:prepare".
All the steps done by the maven-release-plugin could also be done by hand, but that's asking for mistakes.
The instructions here seem very clear:
http://maven.apache.org/guides/plugin/guide-java-plugin-development.html
However, the first problem I run into is that the dependencies are wrong. I also needed to reference the maven-plugin-annotations dependency.
Then, when I attempt to run I get the "No plugin descriptor found at META-INF/maven/plugin.xml" error. I haven't figured out what to do about that.
I've found lots of pages referencing the maven-plugin-plugin, but I can't figure out how to add it to the pom so that it actually does anything which allows my own plugin to run.
Is there an updated version of the plugin development instructions which actually mentions the need to use maven-plugin-plugin?
If I can't get this to work I'm just going to go back to using exec-maven-plugin. It's uglier, but at least it works easily.
There are actually several terrific resources from Sonatype for learning how to write plugins:
Maven the Complete Reference: Writing Plugins
Maven Cookbook: Creating an Ant Maven Plugin
Maven Cookbook: Writing Plugins in Groovy
If I recall correctly, you need to configure the maven-plugin-plugin this way to avoid the "No plugin descriptor found..." issue.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-plugin-plugin</artifactId>
<version>3.2</version>
<configuration>
<!-- see http://jira.codehaus.org/browse/MNG-5346 -->
<skipErrorNoDescriptorsFound>true</skipErrorNoDescriptorsFound>
</configuration>
<executions>
<execution>
<id>mojo-descriptor</id>
<goals>
<goal>descriptor</goal>
</goals>
</execution>
</executions>
</plugin>
I forked a simple GitHub project called maven-wrapper (port of the Gradle wrapper) to make it a Maven plugin.
"It should be easy" for you to figure out pieces that you may eventually be missing:
Maven wrapper plugin(Mojo)
Maven Wrapper full POM