Skip to main content

Maven Tips... and Tricks

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...


Popular posts from this blog

Always Use StringBuilder while concatenating Strings within loops

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.


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 it takes to be executed:

Now, bellow is the code you should stick with, …

When to use NOSQL - An opinion based post of 2014...

In the last weeks, I've been hearing a lot about Cassandra, and other NoSQL Solutions that were candidates to one of the projects I am working on. Which is currently set to function properly with a RDBMS solution - Oracle 11g.

I decided then to take a deeper look into those kind of solution, NoSQL solutions, and compare them with RDBMS solutions. This article is intended to help you understand NoSQL, and pick the solution that best fits your requirements and scenario. This article does not cover all the features of a Specific NoSQL solution, rather it shows the general scenario.

In order to fully understand NoSQL, let us first see some key concepts of distributed computer systems and storage systems.

What is NoSQL?

A NoSQL or Not Only SQL database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases. Motivations for this approach include simplicity of design, horizontal scaling and finer contro…