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How to add java library without no repository to pom file?

I'd like to add one project A as my dependency, but unfortunately, there's no repository host this library. I know that I can install it to local repository manually, then refer this in pom file. But I have a travis build job where there's no such artifact, is there any way that I can install this library to local repo automatically ? Thanks

I would recommend to use the clean approach and uploading this library into your own repository. If you don't have one: time to get one running.
If you're really not up to this task the maven install plugin: http://maven.apache.org/plugins/maven-install-plugin/install-file-mojo.html can install a jar in the local repository. This will work both locally and on a CI server.
To upload a jar in a remote repository there is the deploy plugin: http://maven.apache.org/plugins/maven-deploy-plugin/deploy-file-mojo.html
If you bind the execution of this plugin to a very early phase in the maven life-cycle (validate) you might be able to avoid a build step required prior of your own build.

What is the difference between Maven build and Maven build... in Eclipse?

I am new to eclipse and programming , so probably a silly question.
According to me build just makes jar file but maven install deploys it to local repo thats m2 .
Also there are two options for build ->maven build and-> maven build..
Could u explain me the explain mw the difference between two.

maven build... lets you specify goal and various other build parameter (build profile, offline, update snapshot, other build parameter etc..)
maven build is a pre-defined goal that eclipse maven plugin wraps under,
You could see the first couple line of output for both of the case

Build - Maven phase - compile and prepare ready to distribute package - eg. JAR
Build... - opens eclipse wizzard where you can customize the build
Install - Maven phase - do the same as with Build and install to local artifact (product of Build phase) to local or remote repository. This will allow to use that project as dependency in other projects.

Eclipse maven build does not install dependencies

I'm working in eclipse on a java / javascript project, we're using maven to manage our project dependencies, I ran into a issue with maven build (clean install) does not install the dependencies that I specified in the POM.xml file, I tried everything I can find on the internet the whole day today, still no luck, I'll be really appreciate if anyone could kindly take a look at, thank you :)
I got a reuse lib project (lib) and a working project (project), the project should be installing the lib during the maven build, So, here's more detail information on what exactly I did:
I ran maven clean on the lib, then ran maven package, the lib-1.0.0-SNAPSHOT.jar file was generated successfully.
then in the working project POM.xml file, I added the dependency declaration.
I right clicked the working project, maven -> update maven project, where I checked the 'force update of snapshots / releases' checkbox, then -> ok
I right clicked the working project, run as -> maven build (with clean install, and also I checked on the 'Update Snapshots' checkbox) -> apply -> run
In the console, I saw the reuse lib was downloading and then downloaded, but it's never got installed (there should be a line says installing reuse lib...), as the result of it, the reuse lib will not be loaded after I ran my working project, it drives me insane -_-!..

Only your maven projects build output can be installed (in the local repository with mvn install, resp. mvn clean install). During the build it will resolve the dependencies (and the transitive dependencies) to be downloaded and packed to your delivery. Those dependencies of your project will implicitly also be "installed" in your local repository since you will see them in your local repository after the download happened - Maven will however not see that as a install in the meaning of install of the default lifecycle.
To install your "reuse lib"-Maven project you will have to run mvn install or mvn clean install on that project's pom rather than on a project which "just uses it as dependency".

Quickest POM settings to turn an existing Eclipse web project in a Maven-managed project?

I'm converting an existing Eclipse-based web project to a Maven-managed one.
Since the project has lots of dependencies, many of which are custom (they're either internally made or they've been taken from sources that have no public repository), is there some 'magic' Maven POM setting that will let me load every jar from WebContent/WEB-INF/lib and make the project work as before right now, so that I can configure each dependency and do the necessary refactoring to turn it to a proper Maven project with a little more time and care?
I have already seen this question, but the project must continue to compile inside Eclipse, so - or at least I guess - it is not just a matter of using the Maven war plugin

What you want to do is called "installing" your non-mavenized JARs into your maven repository. This can be a local or remote repo that you host.
The command to install to your local repo is something like this: mvn install:install-file -Dfile=My-lib.jar -DgroupId=com.mycompany -DartifactId=My-lib -Dversion=1.2.3 -Dpackaging=jar
You'll want to review the various options for install to suit your project.
Once the non-mavenized dependencies are installed to your repo you can add them to your pom like any other maven dependency. They will be fetched from your local repo.
You will have to set up your own remote repo (like Artifactory) or install each plugin for every developer and CI server in your environment for others on your team to build the project. I strongly reccomend Artifactory, it makes it easy on your and your team to use maven and get dependencies.

Travis CI not using extra Maven repository provided in pom.xml

I have a Java-based GitHub project, fitnessjiffy-spring (I'm currently focused on the "bootstrap" branch). It depends on a library built from another GitHib project, fitnessjiff-etl. I am trying to configure both of these to be built by Travis CI.
Unfortunately, Travis is not as sophisticated as Jenkins or Hudson in dealing with Maven-based Java projects. Jenkins can easily handle dependencies between projects, but the same concept doesn't seem to exist with Travis. If one project depends on another, then that other project must already be built previously... and its artifact uploaded to some Maven repo where the first project can download it later.
My "fitnessjiffy-etl" library is building and deploying just fine. I'm using Bintray for Maven repository hosting, and you can clearly see my artifacts over plain HTTP at:
http://dl.bintray.com/steve-perkins/maven/
In my "fitnessjiffy-spring" project, I am adding this Maven repo location directly in the pom.xml, so that Travis will be able to find that artifact dependency. Here is the state of my POM at the time of this writing. Note the <repositories> element at the bottom of the file.
When I build this project locally, it works just fine. I can see it downloading the Maven artifact from "http://dl.bintray.com/...". However, when I try to build on Travis CI it fails every time. I can see in the console log that Travis is still trying to download the artifact from Maven Central rather than my specified repo.
Does this make sense to anyone else? Why does Maven utilize a custom repository location in a POM file when building locally, but ignores this configuration when running on a Travis CI build?

From digging into this further, I discovered that Travis uses its own proxy for Maven Central, and has configured Maven to force ALL dependency requests through their proxy. In other words, it does not seem possible at this time to use additional Maven repos specified in the POM file of a project built on Travis.
In my case, I ended up refactoring such that project would not need the outside JAR dependency. I also switched to Drone.io, so I could manage my settings on the build server rather than having to carry a YAML file in my repository (which always struck me as a bit daft).
However, even on Drone it's still a major hassle to manage dependencies between multiple projects (extremely common with Java development). For Java, I just don't think there's currently an adequate substitute for Jenkins or Hudson, maybe running on a cheap Digital Ocean droplet or some other VPS provider instance.

In your install phase add a $HOME/.m2/settings.xml define your custom repository.
cache:
directories:
- "$HOME/.m2"
install:
- curl -o $HOME/.m2/settings.xml
https://raw.githubusercontent.com/trajano/trajano/master/src/site/resources/settings.xml
- mvn dependency:go-offline
script:
- mvn clean install site