How does mvn clean install works
mvn install should execute all the phases before install phase, that means it will first run the surefire test and then later update m2 respository with the dependency
Yes, this is how it works.
The phases are executed in order and the installation into the local repository is the last one.
With external dependencies it's simple: before compiling anything Maven downloads them.
With inter-module dependencies it's more complicated. It's important to understand that Maven first runs all phases for the 1st module, then runs all phases for the 2nd module, and so on. So depending on which phase you call there either will be a JAR file or there won't be.
Maven will try to give you as "high-quality" dependency as possible, meaning:
if you run mvn install - this will put 1st module's jar into ~/.m2, then by the time 2nd module starts - it already has a JAR dependency waiting in the local repo.
if you run mvn package the JAR doesn't go to local repo, it stays in target/. Thus this target/xxx.jar will be used as a dependency.
if you run mvn test there won't even be a JAR. There will only be target/classes. So 2nd module's compilation & runtime will have directory with classes & resources in its classpath (no JAR).
PS: this may actually lead to real implications. When you run tests in module2 you may be reading resources of module1 and working with their file paths. And everything will work fine in case of mvn test. But once you start running at least mvn package there won't be files anymore - all resources of module2 will be in JAR and thus can be accessed only with getResourceAsStream().
Related
I have a default maven project:
/src/main/java
/src/test/java (include *Test.java).
When I exeucte "mvn compile", maven also tries to compile the testClasses under /src/test/java. This fails, as of some dependencies such as JUnit are under "test"-scope. Changing the scope of e.g. JUnit to "provided" everything works fine.
How can I avoid maven to compile testClasses when compiling? In my understanding, I expect to maven to compile this files only when executing "testcompile".
I am using maven 2.2.1
I believe it is nothing to do with the scope of JUnit. Normally we set JUnit's scope to test (instead of provided) and everything is just fine.
src/test/java is compiled by Maven Compiler Plugin's testCompile goal. However, you don't need to explicitly run that goal. Please have a look in topics about Maven's Lifecycle. For example, if you run maven install, it is implicitly going through many phases (e.g. compile, compile test, generate resources etc), and many of them is bounded to a default plugin goal.
If you want to avoid test source from building, from Maven Compiler Plugin's usage page, compiler:testCompile will be skipped if you turn off testing by setting maven.test.skip=true
So, if your unit tests are not yet ready, just build with Maven, with -Dmaven.test.skip=true parameter.
Just to add, this is absolutely not a good practice to assume "unit test failing" being normal during development.
Just use the skip parameter for the maven-surefire-plugin which skip tests as well as compiling the test.
The pom.xml had defined "sourceDirectory" incorrectly. Removing it fixed the issue
Instead of command "maven clean compile" , use "mvn -B -Dmaven.test.skip=true clean compile". This parameter skips test.
I have a multi-module maven project (maven 2.2.1).
One of the module is a maven plugin.
This plugin is bound to the compile phase of another module, and added as a direct dependency to trigger correct reactor ordering of module's building.
If I run 'mvn clean install' on the root module, with a fresh local repository, everything goes fine (build, test, install). (I precise that my project's artifacts are not deployed anywhere, only installed locally in my machine's local repo).
BUT if I delete my local repository, and perform 'mvn test', the plugin module is reported as missing ? Whereas, the build order is correct, the plugin module is built succesfully before the module using it ???
Is there any special treatment of maven module with 'maven-plugin' packaging ?
I don't understand why other project inter modules dependencies are resolved correctly and not this specific one !
The problem is that a Maven Plugin must be installed into the local repository first before you can use a plugin as a dependency (or better be part of the life-cycle).
In maven, what does "-e" stands for in the following command.
mvn -e clean install
Moreover, what is the difference between
mvn clean install
and
mvn clean compile
As Satish stated, the "-e" switch will display execution errors in the maven output.
As to the difference in "install" vs "compile", those are different Maven lifecycle stages. See the Introduction to the Build Lifecycle documentation for help with that. The key to remember is that Maven will execute all lifecycle stages up to and including the one you specify, and then stop.
Specifically in your case, "mvn clean compile" will run Maven with two lifecycle targets, the first being "clean", and the second being "compile". The "compile" lifecycle phase will run the build up to and including the compilation of project source code. The "install" lifecycle phase will run all the way through packaging your project into it's container (jar, war, etc) and will install it to your local maven repository, which resides on your local machine. When a project is installed to your local repository, other projects you build on your machine can reference it without having to have any knowledge of where the source code or project build artifacts actually reside.
the e flag (e = errors) prints out more detailed error messages.
mvn clean install, does compilation, linking and installs (copies to app server etc)
for more maven options look at this ref card
http://www.scribd.com/doc/15778516/DZone-Refcard-55-Apache-Maven-2
or maven command list
http://cvs.peopleware.be/training/maven/maven2/mvnCommand.html
mvn clean install - First, cleans already compiled class files (probably in target/ directory). Then, it compiles the classes, generate the jar, and then install the created jar to your local m2 repository (probably located at ~/.m2/repository/).
mvn clean compile - The clean does the same thing as above. And, then, it compiles the java files in the project. And, stops there. It doesn't create the jar nor install anything to the local maven repository.
-e switch will display the stack-traces occur when your build is failed. It's a normal stack-trace that java programs produce when exceptions occur. Do note that Maven itself is a Java program.
I have an artifact abc which has some tests. I have different versions of abc within my repository. I now want to be able to run the latest tests against the 'old build' of the project.
I tried to add the artifact itself to the test dependencies but this (of course) results in a cyclic reference error of the maven reactor when building the tests via:
mvn compiler:testCompile
mvn surefire:test
Is there any smart way to run tests against a previous old build/artifact?
Must i create a new pom.xml in which i define the solo test execution?
Or should i add a postfix to my current artifact when executing the tests? (This would avoid a cyclic reference error)
Separate the tests out into a separate module/project that depends on the classes it tests. Then create separate profiles where you change the dependency to be on older releases.
The problem I foresee with what you're trying to do is that the package phase comes after the test phase of the maven lifecycle. Which to me implies that maven runs unit tests against the compiled classes and not the physical jar file (generated in the package phase). You'll therefore have to replace the contents of the projects /target/classes folder with the classes in the "older" jar.
I've been seeing odd behaviour from my Maven 2.2.1 installation whilst doing war installs.
Occasionally, I will update a class but the updated version is not packaged up in the artifact produced by mvn install.
So far, I have determined that an updated .class file is produced in the target directory, and that the class of the same name in the produced .war is not the same (different date modified, different size)
Running Maven from the command line with the -X flag produced debug output for the class like:
[DEBUG] *
WEB-INF/classes/mypackage/MyClass.class
is up to date.
I think I've also had the same problem before where the file that was cached(?) was an incomplete compile from Eclipse, causing 'Unresolved Compilation Problem' errors from the Maven build, but a working artifact from an Eclipse export.
How does Maven determine whether a
file 'is up to date' during the
install process?
Where are the files Maven is comparing to?
Can I force Maven to build a package from scratch?
Any other ideas would be appreciated!
So far, I have determined that an
updated .class file is produced in the
target directory, and that the class
of the same name in the produced .war
is not the same (different date
modified, different size)
Just to be sure, the classes should be built under target\classes, not target.
Can I force Maven to build a package from scratch?
You can force a full build by running
mvn clean install
This performs a clean (essentially removes the target directory) before running the install phase.
Also - check for copies of your classes outside of the Maven build directory. In this case as it is a webapp, check src/main/webapp/WEB-INF/classes