What is mvn clean install

The only thing I can say for sure from the top of my head is that you can force Maven to always fetch dependencies by using -U :. Git is a version control System and its main purpose is to track the changes you make to files, so you have a record of what has been done. Maven is an automation and management tool. It helps to build Projects, dependency and documentation. It simplifies the build process. The only case when the two workflows would overlap , is when maven is used to makes some changes in your source files like applying formatting , adding LIcenece headers etc.

Thats when you would probably run a mvn clean install before git add , other wise the work flows are independent of each other. After making changes in my code base, when is the mvn clean install effective to a commit? Maven usually is smart enough to deal with whatever is left over in the target directory. One could argue that in the case of java or JVM based projects this would be a tough task anyway.

Think about inner or anonymous classes. What the clean goal is doing is to try to delete every target folder in every module of your project. Only for it to be created again immediately by the next lifecycle phase.

Now the tricky question: if you change something in the core module, will the dependant cli or web modules automatically pick up those changes on the next build? As everything in IT the answer to that question of course is: it depends! The very unintuitive default for maven is to look up dependencies in your local maven repository.

This default also applies to dependencies if they happen to be located in the very same multi module project. Now the quick fix of course is to run install. Keep in mind, that when you execute the clean goal of Maven, the target directory is removed, meaning you lose all compiled classes from previous builds. That means, that Maven will have to build all of your project again from scratch, rather than being able to just compile the classes that were changed since last build.

This slows your build time down. However, sometimes it can be nice to have a clean, fresh build, e. This command consists of the mvn command which executes Maven, and the build life cycle named clean. This maven command executes the clean build life cycle and the install build phase in the default build life cycle. You might wonder how you see the difference between a build life cycle, build phase and build goal.

I will get back to that later. As mentioned in the introduction in the section about Build life cycles, build phases and build goals , Maven contains three major build life cycles:. Inside each build life cycle there are build phases, and inside each build phase there are build goals. You can execute either a build life cycle, build phase or build goal. When executing a build life cycle you execute all build phases and thus build goals inside that build life cycle.

When executing a build phase you execute all build goals within that build phase. Maven also executes all build phases earlier in the build life cycle of the desired build phase. Buid goals are assigned to one or more buid phases.

When the build phases are executed, so are all the goals in that build phase. You can also execute a build goal directly. When you run the mvn command you pass one or more arguments to it. These arguments specify either a build life cycle, build phase or build goal. For instance to execute the clean build life cycle you execute this command:.

The default life cycle is the build life cycle which generates, compiles, packages etc. You cannot execute the default build life cycle directly, as is possible with the clean and site. Instead you have to execute a specific build phase within the default build life cycle.