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Ant is simply a toolbox whereas Maven is about the application of patterns in ORDER to achieve an infrastructure which displays the characteristics of visibility, reusability, maintainability, and comprehensibility. It is wrong to CONSIDER Maven as a build tool and just a REPLACEMENT for Ant.

Ant is simply a toolbox whereas Maven is about the application of patterns in order to achieve an infrastructure which displays the characteristics of visibility, reusability, maintainability, and comprehensibility. It is wrong to consider Maven as a build tool and just a replacement for Ant.

A mojo is a Maven plain Old Java Object. Each mojo is an executable GOAL in Maven, and a PLUGIN is a DISTRIBUTION of one or more RELATED mojos.

A mojo is a Maven plain Old Java Object. Each mojo is an executable goal in Maven, and a plugin is a distribution of one or more related mojos.

It MEANS that you have executed a PLUGIN multiple times with the same &LT;id>. Provide each <EXECUTION> with a unique <id> then it WOULD be ok.

It means that you have executed a plugin multiple times with the same <id>. Provide each <execution> with a unique <id> then it would be ok.

SET &LT;INHERITED&GT; to FALSE.

set <inherited> to false.

You can put the CLEAN plugin INSIDE the EXECUTION TAG in pom.xml FILE

You can put the clean plugin inside the execution tag in pom.xml file

Any TRANSITIVE DEPENDENCY can be exclude using "exclusion" element. As example, A depends UPON B and B depends upon C then A can MARK C as excluded.

Any transitive dependency can be exclude using "exclusion" element. As example, A depends upon B and B depends upon C then A can mark C as excluded.

Any transitive dependency can be marked as optional using "optional" element. As EXAMPLE, A DEPENDS UPON B and B depends upon C. Now B marked C as optional. Then A will not use C.

Any transitive dependency can be marked as optional using "optional" element. As example, A depends upon B and B depends upon C. Now B marked C as optional. Then A will not use C.

Dependency with scope system are always available and are not looked up in repository, they are usually used to TELL MAVEN about DEPENDENCIES which are provided by the JDK or the VM. Thus, system dependencies are especially useful for RESOLVING dependencies on artifacts which are now provided by the JDK.

Dependency with scope system are always available and are not looked up in repository, they are usually used to tell Maven about dependencies which are provided by the JDK or the VM. Thus, system dependencies are especially useful for resolving dependencies on artifacts which are now provided by the JDK.

USING the EXCLUSION ELEMENT.

Using the exclusion element.

USE the COMMAND: MVN o PACKAGE.

Use the command: mvn o package.

It uses less storage, it MAKES checking out project QUICKER, non NEED for versioning JAR FILES.

It uses less storage, it makes checking out project quicker, non need for versioning JAR files.

To GIVE PORTABILITY to projects ( e.g. WINDOWS, LINUX etc).

To give portability to projects ( e.g. windows, linux etc).

&LT;repositories&GT;, <pluginRepositories>,<DEPENDENCIES>, <plugins> ,<PROPERTIES>, <modules><REPORTING>,<dependencyManagement>,<distributionManagement>

<repositories>, <pluginRepositories>,<dependencies>, <plugins> ,<properties>, <modules><reporting>,<dependencyManagement>,<distributionManagement>

PROFILES are SPECIFIED using a SUBSET of the elements available in the POM itself.

Profiles are specified using a subset of the elements available in the POM itself.

All POMS inherit from a parent (despite explicitly defined or not). This base POM is known as the SUPER POM, and CONTAINS VALUES INHERITED by default.

All POMs inherit from a parent (despite explicitly defined or not). This base POM is known as the Super POM, and contains values inherited by default.

&LT;groupId&GT;:<artifactId>:<VERSION>

<groupId>:<artifactId>:<version>

The <EXECUTION&GT; element CONTAINS information's required for the execution of a PLUGIN.

The <execution> element contains information's required for the execution of a plugin.

pom.

pom.

Some of the VALID PACKAGING VALUES are JAR, war, ear and pom. If no packaging value has been specified, it will default to jar.

Some of the valid packaging values are jar, war, ear and pom. If no packaging value has been specified, it will default to jar.

To reference a property DEFINED in your pom.xml, the property name uses the names of the XML elements that DEFINE the VALUE, with "pom" being allowed as an alias for the PROJECT (root) element.

So ${pom.name} refers to the name of the project, ${pom.version} refers to the version of the project, ${pom.build.finalName} refers to the final name of the file CREATED when the built project is packaged, etc.

To reference a property defined in your pom.xml, the property name uses the names of the XML elements that define the value, with "pom" being allowed as an alias for the project (root) element.

So ${pom.name} refers to the name of the project, ${pom.version} refers to the version of the project, ${pom.build.finalName} refers to the final name of the file created when the built project is packaged, etc.

{groupId,artifactId,TYPE,CLASSIFIER}.

{groupId,artifactId,type,classifier}.

Dependency SCOPE includes dependencies as per the current stage of the build. Various Dependency Scopes are −

• compile − This scope indicates that dependency is available in classpath of project. It is DEFAULT scope.
• provided − This scope indicates that dependency is to be provided by JDK or web-Server/Container at runtime.
• runtime − This scope indicates that dependency is not REQUIRED for compilation, but is required during execution.
• test − This scope indicates that the dependency is only available for the test compilation and execution phases.
• system − This scope indicates that you have to PROVIDE the system path.
• import − This scope is only used when dependency is of type pom. This scope indicates that the specified POM should be replaced with the dependencies in that POM's section.

Dependency scope includes dependencies as per the current stage of the build. Various Dependency Scopes are −

Maven DETERMINES what version of a dependency is to be USED when multiple versions of an ARTIFACT are encountered. If TWO dependency versions are at the same DEPTH in the dependency tree, the first declared dependency will be used. This is called dependency mediation.

Maven determines what version of a dependency is to be used when multiple versions of an artifact are encountered. If two dependency versions are at the same depth in the dependency tree, the first declared dependency will be used. This is called dependency mediation.

It means to directly SPECIFY the versions of artifacts to be used when they are encountered in transitive DEPENDENCIES. For an example project C can include B as a dependency in its dependencyManagement section and directly control which version of B is to be used when it is EVER REFERENCED.

It means to directly specify the versions of artifacts to be used when they are encountered in transitive dependencies. For an example project C can include B as a dependency in its dependencyManagement section and directly control which version of B is to be used when it is ever referenced.

Transitive dependency means to AVOID needing to DISCOVER and specify the LIBRARIES that your own DEPENDENCIES require, and including them automatically.

Transitive dependency means to avoid needing to discover and specify the libraries that your own dependencies require, and including them automatically.

In CASE of Version, if Maven once DOWNLOADED the mentioned version say data-service:1.0, it will never try to download a newer 1.0 AVAILABLE in repository. To download the updated code, data-service version is be UPGRADED to 1.1.
In case of SNAPSHOT, Maven will automatically fetch the latest SNAPSHOT (data-service:1.0-SNAPSHOT) everytime app-ui team BUILD their project.

In case of Version, if Maven once downloaded the mentioned version say data-service:1.0, it will never try to download a newer 1.0 available in repository. To download the updated code, data-service version is be upgraded to 1.1.
In case of SNAPSHOT, Maven will automatically fetch the latest SNAPSHOT (data-service:1.0-SNAPSHOT) everytime app-ui team build their project.

SNAPSHOT is a special version that indicates a current development COPY. Unlike regular versions, Maven checks for a new SNAPSHOT version in a REMOTE repository for every BUILD.

SNAPSHOT is a special version that indicates a current development copy. Unlike regular versions, Maven checks for a new SNAPSHOT version in a remote repository for every build.

TYPE the following command: mvn ARCHETYPE:GENERATE

Type the following command: mvn archetype:generate

Archetype is a Maven plugin whose task is to CREATE a PROJECT structure as PER its template.

Archetype is a Maven plugin whose task is to create a project structure as per its template.

External dependencies (LIBRARY JAR location) can be configured in pom.xml in same way as other dependencies.

• Specify groupId same as name of the library.
• Specify artifactId same as name of the library.
• Specify SCOPE as system.
• Specify system path RELATIVE to PROJECT location.

External dependencies (library jar location) can be configured in pom.xml in same way as other dependencies.

MAVEN dependency MANAGEMENT using concept of Maven REPOSITORIES (Local, Central, REMOTE). Suppose dependency is not available in any of remote repositories and central repository; in such scenarios Maven uses concept of External Dependency.

Maven dependency management using concept of Maven Repositories (Local, Central, Remote). Suppose dependency is not available in any of remote repositories and central repository; in such scenarios Maven uses concept of External Dependency.

Maven provides following TWO TYPES of Plugins:

1. Build plugins:They execute during the build and should be CONFIGURED in the element of pom.xml
2. REPORTING plugins:They execute during the SITE generation and they should be configured in the element of the pom.xml

Maven provides following two types of Plugins:

MAVEN PLUGINS are USED to:

• CREATE jar file.
• create war file.
• compile code files.
• unit testing of code
• create project documentation.
• create project REPORTS.

Maven Plugins are used to:

Following is the search pattern:

Step 1 − Search dependency in local repository, if not found, move to step 2 else if found then do the further processing.

Step 2 − Search dependency in CENTRAL repository, if not found and remote repository/repositories is/are mentioned then move to step 4 else if found, then it is downloaded to local repository for future reference.

Step 3 − If a remote repository has not been mentioned, MAVEN simply stops the processing and throws error (Unable to find dependency).

Step 4 − Search dependency in remote repository or repositories, if found then it is downloaded to local repository for future reference otherwise Maven as EXPECTED stop processing and throws error (Unable to find dependency).

Following is the search pattern:

Step 1 − Search dependency in local repository, if not found, move to step 2 else if found then do the further processing.

Step 2 − Search dependency in central repository, if not found and remote repository/repositories is/are mentioned then move to step 4 else if found, then it is downloaded to local repository for future reference.

Step 3 − If a remote repository has not been mentioned, Maven simply stops the processing and throws error (Unable to find dependency).

Step 4 − Search dependency in remote repository or repositories, if found then it is downloaded to local repository for future reference otherwise Maven as expected stop processing and throws error (Unable to find dependency).

Sometimes, Maven does not find a mentioned dependency in central repository as well then it stops the build process and output error MESSAGE to CONSOLE. To prevent such situation, Maven PROVIDES concept of Remote Repository which is DEVELOPER's own custom repository containing REQUIRED libraries or other project jars.

Sometimes, Maven does not find a mentioned dependency in central repository as well then it stops the build process and output error message to console. To prevent such situation, Maven provides concept of Remote Repository which is developer's own custom repository containing required libraries or other project jars.

It is repository provided by Maven COMMUNITY. It contains a large number of commonly used libraries. When Maven does not FIND any dependency in LOCAL repository, it starts searching in central repository using following URL: http://repo1.maven.org/maven2/.

It is repository provided by Maven community. It contains a large number of commonly used libraries. When Maven does not find any dependency in local repository, it starts searching in central repository using following URL: http://repo1.maven.org/maven2/.

MVN INSTALL.

mvn install.

~/m2./repository.

~/m2./repository.

MAVEN local repository is a FOLDER location on your machine. It gets CREATED when you run any maven command for the first time. Maven local repository keeps your project's all DEPENDENCIES (LIBRARY jars, plugin jars etc).

Maven local repository is a folder location on your machine. It gets created when you run any maven command for the first time. Maven local repository keeps your project's all dependencies (library jars, plugin jars etc).

MAVEN REPOSITORY are of three TYPES:

1. LOCAL
2. central
3. remote

Maven repository are of three types:

A repository is a place i.e. directory where all the project jars, LIBRARY JAR, plugins or any other project specific artifacts are stored and can be used by Maven EASILY.

A repository is a place i.e. directory where all the project jars, library jar, plugins or any other project specific artifacts are stored and can be used by Maven easily.

A Maven Build PROFILE can be activated in various ways −

• EXPLICITLY using COMMAND console input.
• Through maven settings.
• BASED on environment VARIABLES (User/System variables).
• OS Settings (for example, Windows family).
• Present/missing files.

A Maven Build Profile can be activated in various ways −

BUILD profiles are of three TYPES :

• PER Project − DEFINED in the project POM file, pom.xml.
• Per User − Defined in MAVEN settings xml file (%USER_HOME%/.m2/settings.xml).
• Global − Defined in Maven global settings xml file (%M2_HOME%/conf/settings.xml)

Build profiles are of three types :

A Build PROFILE is a set of configuration values which can be USED to set or OVERRIDE default values of Maven build. USING a build profile, you can customize build for different ENVIRONMENTS such as Production v/s Development environments.

A Build profile is a set of configuration values which can be used to set or override default values of Maven build. Using a build profile, you can customize build for different environments such as Production v/s Development environments.

The PHASES in SITE LIFECYCLE are:−

• pre-site
• site
• post-site
• site-deploy

The phases in Site Lifecycle are:−

The CLEAN LIFECYCLE CONSISTS of the FOLLOWING PHASES:

• pre-clean.
• clean.
• post-clean.

The clean lifecycle consists of the following phases:

This COMMAND will clean the project, copy the DEPENDENCIES and PACKAGE the project (executing all PHASES up to package).

This command will clean the project, copy the dependencies and package the project (executing all phases up to package).

A goal represents a specific task which contributes to the BUILDING and managing of a project. It may be bound to ZERO or more build PHASES. A goal not bound to any build phase could be executed OUTSIDE of the build lifecycle by DIRECT invocation.

A goal represents a specific task which contributes to the building and managing of a project. It may be bound to zero or more build phases. A goal not bound to any build phase could be executed outside of the build lifecycle by direct invocation.

Following are the phases:−

• validate − validate the project is CORRECT and all necessary information is available.
• compile − compile the source code of the project.
• test − test the compiled source code using a suitable unit testing framework. These tests should not require the code be packaged or deployed
• package − TAKE the compiled code and package it in its distributable format, such as a JAR.
• integration-test − process and deploy the package if necessary into an environment where integration tests can be RUN.
• verify − run any checks to verify the package is VALID and meets quality criteria.
• install − install the package into the local repository, for use as a dependency in other projects locally.
• deploy − done in an integration or release environment, copies the FINAL package to the remote repository for sharing with other developers and projects.

Following are the phases:−

This COMMAND removes the TARGET DIRECTORY with all the build data before STARTING the build process.

This command removes the target directory with all the build data before starting the build process.