Skip to main content

Maven Tips... and Tricks

By
Maven, one of the central actors in the Java World, resposible for managing the building life-cycles of many projects, is full of little features, that sometimes we forget to explore.

Let us go straight away and take a look at some very useful Maven features that will make your builds shine.

From where it stopped


Sometimes it is needed to build a bunch of projects all together, artifact-a, artifact-b and so on. What do we usually do when one of them fail? Build it all again!

But not anymore:


By using this option you can run the build from the project that failed.

Two out of ten

Ok, suppose you have 10 projects, and you only want to build 2 of them, how would you do?

The option -pl will do the job


Multi-threaded Build

If in the machine you run the build you have many Cores, tou can take advantage of them by using the following option(it means 2 Threads per Core):

It is also possible to define 3 Threads per Core(T3C)

Skip your Tests when you want to

With a lot of tests to perform your complete phases might really take too long and sometimes you only want to test a new or small functionality, you might skip the Tests by using the DskipTests


Running Offline

Wanna run your builds without maven connecting to repositories, checking for updates? You asked you got it!

When running with the offline option enabled, Maven will not attempt to connect to a remote repository to retrieve artifacts.
Bonus - Deal with failures

The following options control how Maven reacts to a build failure in the middle of a multi-module project build: 

Only fail the build afterwards; allow all non-impacted builds to continue


Stop at first failure in reactorized builds


NEVER fail the build, regardless of project result

The -fn and -fae options are useful options for multi-module builds that are running within a continuous integration tool like Hudson. The -ff option is very useful for developers running interactive builds who want to have rapid feedback during the development cycle.

That's all for today, hope your builds will never be the same...

Comments

Post a Comment

Popular posts from this blog

Always Use StringBuilder while concatenating Strings within loops

By
A common tendency of Java programmers is to always concatenate Strings using + operator. Which is actually very good, and simplifies the code by improves readability, since we would have to use StringBuilder.append(String), if the single + operator was not allowed. In fact if we look in byte code generate from such concatenation style, we will see a StringBuilder being used to perform the action. Check the JSL:    JLS Now , the point is, although this facility, you should not use the + operator in loop concatenation. Why? A new  StringBuilder  Object will be constructed at every single loop iteration (with initial value of str) and at the end of every iteration there will be concatenation with initial String (actually  StringBuilder  with initial value of  str ). So you need to create StringBuilder by yourself only when you work with String concatenation in loop. Let us procuce the evidence First, run this code, and see how long i...
Post a Comment
Read more

Understanding What Instrumentation is

By
It would be possible to change the Java bytecode of your classes? It would be possible to create new procedures and change the body of his methods, even at runtime? Yes, the answer is yes, this is possible! Thanks to the APIs lowest level or higher level as java.lang.instrumentat and Apache BCEL among others.   For better transparency, you can always automatically generate code and add it to their classes. There are several frameworks. The java developer may be adding a simple enhancer code in their applications, which is relatively easy to do, with little intrusion into your creative process. Byte code enhancement Programs written in Java to compile a form of code called bytecode. The idea is through instrumentation, inject byte code to add services and still maintain transparency. For example, most implementations use an enhancer JDO bytecode. Another excellent example was a project at IBM where test scenarios were created dynamically through bytecode instrumentation. Of...
Post a Comment
Read more