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Maven Plugin Guide

Table of Contents

Making open source more inclusive

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1. Introduction

1.1. About the Maven Plugin Guide

This guide is for engineers, consultants, and others who want to use the Migration Toolkit for Runtimes (MTR) to migrate Java applications or other components. It describes how to install and run the Maven plugin, review the generated reports, and take advantage of additional features.

1.2. About the Migration Toolkit for Runtimes

What is the Migration Toolkit for Runtimes?

The Migration Toolkit for Runtimes (MTR) is an extensible and customizable rule-based tool that simplifies the migration and modernization of Java applications.

MTR examines application artifacts, including project source directories and application archives, and then produces an HTML report highlighting areas needing changes. MTR supports many migration paths, including the following examples:

  • Upgrading to the latest release of Red Hat JBoss Enterprise Application Platform

  • Migrating from Oracle WebLogic or IBM WebSphere Application Server to Red Hat JBoss Enterprise Application Platform

  • Containerizing applications and making them cloud-ready

  • Migrating from Java Spring Boot to Quarkus

  • Updating from Oracle JDK to OpenJDK

  • Upgrading from OpenJDK 8 to OpenJDK 11

  • Upgrading from OpenJDK 11 to OpenJDK 17

  • Upgrading from OpenJDK 17 to OpenJDK 21

  • Migrating EAP Java applications to Azure

  • Migrating Spring Boot Java applications to Azure

For more information about use cases and migration paths, see the MTR for developers web page.

How does the Migration Toolkit for Runtimes simplify migration?

The Migration Toolkit for Runtimes looks for common resources and known trouble spots when migrating applications. It provides a high-level view of the technologies used by the application.

MTR generates a detailed report evaluating a migration or modernization path. This report can help you to estimate the effort required for large-scale projects and to reduce the work involved.

How do I learn more?

See the Introduction to the Migration Toolkit for Runtimes to learn more about the features, supported configurations, system requirements, and available tools in the Migration Toolkit for Runtimes.

1.3. About the Maven Plugin

The Maven plugin for the Migration Toolkit for Runtimes integrates into the Maven build process, allowing developers to continuously evaluate migration and modernization efforts with each iteration of source code. It provides numerous reports that highlight the analysis results, and is designed for developers who want updates with each build.

2. Getting started

2.1. Running the Maven Plugin

The Maven plugin is run by including a reference to the plugin inside your application’s pom.xml file. When the application is built, the Maven plugin is run and generates the reports for analysis.

Prerequisites

  • Java Development Kit (JDK) installed.

    MTR supports the following JDKs:

    • OpenJDK 11

    • Oracle JDK 11

  • 8 GB RAM

  • macOS installation: the value of maxproc must be 2048 or greater.

  • The Maven settings.xml file configured to direct Maven to use the JBoss EAP Maven repository.

  • To run the Maven plugin on OpenJDK 17 or Oracle JDK17, you first need to set MAVEN_OPTS on the command line by running the following command:

    export MAVEN_OPTS="--add-modules=java.se --add-opens java.base/java.lang=ALL-UNNAMED --add-opens java.base/java.util=ALL-UNNAMED --add-opens java.base/java.util.stream=ALL-UNNAMED"
Procedure

  1. Add the following <plugin> to your application’s pom.xml file:

    [...]
<plugin>
    <groupId>org.jboss.windup.plugin</groupId>
    <artifactId>mtr-maven-plugin</artifactId>
    <version>1.2.6.GA-redhat-00001</version>
    <executions>
        <execution>
            <id>run-windup</id>
            <phase>package</phase>
            <goals>
                <goal>windup</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <target>eap:7</target> (1)
    </configuration>
</plugin>
[...]

    1. Specify a migration target. At least one migration target must be supplied within the configuration.

  2. Add --add-modules=java.se to the MAVEN_OPTS environment variable.

    export MAVEN_OPTS=--add-modules=java.se

  3. Build the project:

    $ mvn clean install

    You can access the generated reports.

2.2. Running the Maven Plugin with multiple modules

To use the Maven plugin in a project with multiple modules, place the configuration inside the parent’s pom.xml. The Maven plugin will generate a single report that contains the analysis for the parent and any child modules.

Note
 It is strongly recommended to set inherited to false in multi-module projects; otherwise, the Maven plugin will run when each child is compiled, resulting in multiple executions of the Maven plugin against the child modules. Setting inherited to false results in each project being analyzed a single time and drastically decreased run times.

To run the Maven plugin in a project with multiple modules, perform the following steps.

  1. Include the following plugin inside the parent project’s pom.xml. The following is a sample pom.xml for a parent module.

    <plugin>
    <groupId>org.jboss.windup.plugin</groupId>
    <artifactId>mtr-maven-plugin</artifactId>
    <version>1.2.6.GA-redhat-00001</version>
    <inherited>false</inherited>
    <executions>
        <execution>
            <id>run-windup</id>
            <phase>package</phase>
            <goals>
                <goal>windup</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <input>${project.basedir}</input>
        <target>eap:7</target> (1)
        <windupHome>>/PATH/TO/CLI/<</windupHome>
    </configuration>
</plugin>

    1. Specify a migration target. At least one migration target must be supplied within the configuration.

      This pom.xml file differs from the default in the following attributes:

      • inherited: Defined at the plugin level, this attribute indicates whether or not this configuration should be used in child modules. Set to false for performance improvements.

      • input: Specifies the path to the directory containing the projects to be analyzed. This attribute defaults to {project.basedir}/src/main, and should be defined if the parent project does not have source code to analyze.

      • windupHome: A path to an extracted copy of the MTR CLI. This attribute is optional, but is recommended as a performance improvement.

        The above example demonstrates a set of recommended arguments.

  2. Build the parent project. During the build process, the Maven plugin runs against all children in the project without further configuration.

    $ mvn clean install

  3. Once completed, you can access the generated reports. This report contains the analysis for the parent and all children.

2.3. Accessing the report

When you run Migration Toolkit for Runtimes, the report is generated in the OUTPUT_REPORT_DIRECTORY that you specify using the outputDirectory argument in the pom.xml. Upon completion of the build, you will see the following message in the build log.

Windup report created: <OUTPUT_REPORT_DIRECTORY>/index.html

The output directory contains the following files and subdirectories:

<OUTPUT_REPORT_DIRECTORY>/
├── index.html          // Landing page for the report
├── <EXPORT_FILE>.csv     // Optional export of data in CSV format
├── graph/              // Generated graphs used for indexing
├── reports/            // Generated HTML reports
├── stats/              // Performance statistics

See the Reviewing the reports section of the MTR CLI Guide for information on the MTR reports and how to use them to assess your migration or modernization effort.

3. Exporting the report in CSV format

Migration Toolkit for Runtimes (MTR) provides the ability to export the report data, including the classifications and hints, to a flat file on your local file system. The export function currently supports the CSV file format, which presents the report data as fields separated by commas (,).

The CSV file can be imported and manipulated by spreadsheet software such as Microsoft Excel, OpenOffice Calc, or LibreOffice Calc. Spreadsheet software provides the ability to sort, analyze, evaluate, and manage the result data from an MTR report.

3.1. Exporting the report

To export the report as a CSV file, run MTR with the exportCSV argument set to true.

A CSV file is created in the directory specified by the --output argument for each application analyzed. All discovered issues, spanning all the analyzed applications, are included in AllIssues.csv file.

The CSV files are exported to the directory specified by the outputDirectory argument.

3.2. Importing the CSV file into a spreadsheet program

  1. Launch the spreadsheet software, for example, Microsoft Excel.

  2. Choose File → Open.

  3. Browse to the CSV exported file and select it.

  4. The data is now ready to analyze in the spreadsheet software.

3.3. About the CSV data structure

The CSV formatted output file contains the following data fields:

Rule Id

The ID of the rule that generated the given item.

Problem type

hint or classification

Title

The title of the classification or hint. This field summarizes the issue for the given item.

Description

The detailed description of the issue for the given item.

Links

URLs that provide additional information about the issue. A link consists of two attributes: the link and a description of the link.

Application

The name of the application for which this item was generated.

File Name

The name of the file for the given item.

File Path

The file path for the given item.

Line

The line number of the file for the given item.

Story points

The number of story points, which represent the level of effort, assigned to the given item.

Appendix A: Reference material

A.1. About Maven Plugin arguments

The following is a detailed description of the available MTR Maven plugin arguments.

Table 1. MTR Maven plugin arguments
Argument Description

analyzeKnownLibraries

Flag to analyze known software artifacts embedded within your application. By default, MTR only analyzes application code.

Note

This option may result in a longer execution time and a large number of migration issues being reported.

customLoggingPropertiesFile

An absolute path to a logging.properties file that contains a java.util.logging.LogManager logging configuration. If the specified path is invalid, or the option is not specified, then the logging reverts to using the logging.properties file included with the Maven plugin.

disableTattletale

Flag to disable generation of the Tattletale report. If both enableTattletale and disableTattletale are set to true, then disableTattletale will be ignored, and the Tattletale report will still be generated.

enableCompatibleFilesReport

Flag to enable generation of the Compatible Files report. Due to processing all files without found issues, this report may take a long time for large applications.

enableTattletale

Flag to enable generation of a Tattletale report for each application. This option is enabled by default when eap is in the included target. If both enableTattletale and disableTattletale are set to true, then disableTattletale will be ignored, and the Tattletale report will still be generated.

enableTransactionAnalysis

[Technology Preview] Flag to enable generation of a Transactions report that displays the call stack, which executes operations on relational database tables. The Enable Transaction Analysis feature supports Spring Data JPA and the traditional preparedStatement() method for SQL statement execution. It does not support ORM frameworks such as Hibernate.

Note

enableTransactionAnalysis is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

excludePackages

A list of packages to exclude from evaluation. For example, entering "com.mycompany.commonutilities" would exclude all classes whose package name begins with "com.mycompany.commonutilities".

excludeTags

A list of tags to exclude. When specified, rules with these tags will not be processed.

explodedApps

Flag to indicate that the provided input directory contains source files for a single application.

exportCSV

Flag to export the report data to a CSV file on your local file system. MTR creates the file in the directory specified by the outputDirectory argument. The CSV file can be imported into a spreadsheet program for data manipulation and analysis.

includeTags

A list of tags to use. When specified, only rules with these tags will be processed.

inputDirectory

Specify the path to the directory containing the applications to be analyzed. This argument defaults to {project.basedir}/src/main/.

keepWorkDirs

Flag to instruct MTR to not delete temporary working files, such as the graph database and unzipped archives. This is useful for debugging purposes.

legacyReports

Flag to instruct MTR to generate the old format reports instead of the new format reports.

packages

A list of the packages to be evaluated by MTR. This argument is required.

offlineMode

Flag to operate in offline mode, disabling network access features, such as scheme validation. Used to improve performance.

outputDirectory

Specify the path to the directory to output the report information generated by MTR. This argument defaults to {project.build.directory}/windup-report.

overwrite

Flag to force delete the existing output directory specified by outputDirectory. Defaults to true.

Warning

Be careful not to specify a report output directory that contains important information!

sourceTechnologies

A list of one or more source technologies, servers, platforms, or frameworks to migrate from. This argument, in conjunction with the targetTechnologies argument, helps to determine which rulesets are used.

sourceMode

Flag to indicate that the application to be evaluated contains source files rather than compiled binaries. Defaults to true.

targetTechnologies

A list of one or more target technologies, servers, platforms, or frameworks to migrate to. This argument, in conjunction with the sourceTechnologies argument, helps to determine which rulesets are used.

userIgnorePath

Specify a location for MTR to identify files that should be ignored.

userRulesDirectory

Specify a location for MTR to look for custom MTR rules. The value can be a directory containing ruleset files or a single ruleset file. The ruleset files must use the .windup.xml suffix.

windupHome

An optional argument that points to the root of an extracted MTR CLI. By referencing a local installation of the CLI, the Maven plugin has direct access to all of the indexes, resulting in a performance increase.

windupVersion

Specify the version of MTR to run. By default, this is the Maven plugin’s build version.

A.1.1. Specifying the input directory

A path to the file or directory containing one or more applications to be analyzed. This defaults to {project.basedir}/src/main/.

Usage
<inputDirectory>
    <INPUT_ARCHIVE_OR_DIRECTORY>
</inputDirectory>

A.1.2. Evaluating an input file

Depending on whether the input file type provided to the inputDirectory argument is a file or directory, it will be evaluated as follows depending on the additional arguments provided.

Directory
--explodedApp --sourceMode Neither Argument

The directory is evaluated as a single application.

The directory is evaluated as a single application.

Each subdirectory is evaluated as an application.
File
--explodedApp --sourceMode Neither Argument

Argument is ignored; the file is evaluated as a single application.

The file is evaluated as a compressed project.

The file is evaluated as a single application.

A.1.3. Specifying the output directory

Specify the path to the directory to output the report information generated by MTR.

Usage
<outputDirectory>
    <OUTPUT_REPORT_DIRECTORY>
</outputDirectory>

  • If omitted, the report will be generated in the {project.build.directory}/windup-report directory.

  • If the output directory exists, it will be overwritten based on the value of the overwrite argument. This argument defaults to true, and causes MTR to delete and recreate the directory.

A.1.4. Setting the source technology

A list of one or more source technologies, servers, platforms, or frameworks to migrate from. This argument, in conjunction with the targetTechnologies argument, helps to determine which rulesets are used.

Usage
<sourceTechnologies>
    <source>eap:6</source>
</sourceTechnologies>

The sourceTechnologies argument now provides version support, which follows the Maven version range syntax. This instructs MTR to only run the rulesets matching the specified versions. For example, <source>eap:5</source>.

A.1.5. Setting the target argument

A list of one or more target technologies, servers, platforms, or frameworks to migrate to. This argument, in conjunction with the sourceTechnologies argument, helps to determine which rulesets are used. This argument is required

Usage
<targetTechnologies>
  <target>eap:7</target>
</targetTechnologies>

The targetTechnologies argument now provides version support, which follows the Maven Version Range Specification. This instructs MTR to only run the rulesets matching the specified versions. For example, <target>eap:7</target>.

Warning

When migrating to JBoss EAP, be sure to specify the version in the target, for example, eap:6. Specifying only eap will run rulesets for all versions of JBoss EAP, including those not relevant to your migration path.

See Supported migration paths in Introduction to the Migration Toolkit for Applications for the appropriate JBoss EAP version.

A.1.6. Selecting packages

A list of the packages to be evaluated by MTR. It is highly recommended to use this argument.

Usage
<packages>
  <package>
    <PACKAGE_1>
  </package>
  <package>
    <PACKAGE_2>
  </package>
</packages>

  • In most cases, you are interested only in evaluating custom application class packages and not standard Java EE or third party packages. The <PACKAGE_N> argument is a package prefix; all subpackages will be scanned. For example, to scan the packages com.mycustomapp and com.myotherapp, use the following snippet in your pom.xml.

    <packages>
  <package>com.mycustomapp</package>
  <package>com.myotherapp</package>
</packages>

  • While you can provide package names for standard Java EE third party software like org.apache, it is usually best not to include them as they should not impact the migration effort.

A.2. Default logging properties

The default logging.properties file included with the Maven plugin is provided below. This configuration omits many extraneous messages while allowing you to view the progress of the Maven plugin.

Default logging.properties file
# Licensed under the Eclipse Public License version 1.0, available at
# http://www.eclipse.org/legal/epl-v10.html
#

# Additional loggers to configure (the root logger is always configured)
#loggers=
handlers=java.util.logging.ConsoleHandler
.level=INFO
#java.util.logging.ConsoleHandler.level=INFO

#loggers=org.jboss.forge,org.jboss.weld,org.xnio,org.jboss.forge,org.ocpsoft.rewrite,org.jboss.windup.graph.GraphModelScanner,org.jboss.windup.reporting.xml.ClassificationHandler,org.jboss.windup.graph.GraphTyp$
org.jboss.forge.level=SEVERE
org.janusgraph.level=SEVERE
org.janusgraph.diskstorage.berkeleyje.BerkeleyJEKeyValueStore.level=SEVERE
org.janusgraph.diskstorage.berkeleyje.level=SEVERE
org.jboss.weld.level=SEVERE
org.xnio.level=SEVERE
org.jboss.forge.level=SEVERE
org.ocpsoft.rewrite.level=SEVERE
org.jboss.windup.graph.GraphModelScanner.level=SEVERE
org.jboss.windup.reporting.xml.ClassificationHandler.level=SEVERE
org.jboss.windup.graph.GraphTypeManager.level=SEVERE
org.jboss.windup.graph.GraphContextImpl.level=SEVERE
org.jboss.windup.rules.files.FileMapping.level=SEVERE
org.jboss.windup.exec.level=SEVERE
org.jboss.windup.config.level=SEVERE
com.thinkaurelius.level=SEVERE
org.jboss.windup=INFO

A.3. About rule story points

A.3.1. What are story points?

Story points are an abstract metric commonly used in Agile software development to estimate the level of effort needed to implement a feature or change.

The Migration Toolkit for Runtimes uses story points to express the level of effort needed to migrate particular application constructs, and the application as a whole. It does not necessarily translate to man-hours, but the value should be consistent across tasks.

A.3.2. How story points are estimated in rules

Estimating the level of effort for the story points for a rule can be tricky. The following are the general guidelines MTR uses when estimating the level of effort required for a rule.

Level of Effort Story Points Description

Information

0

An informational warning with very low or no priority for migration.

Trivial

1

The migration is a trivial change or a simple library swap with no or minimal API changes.

Complex

3

The changes required for the migration task are complex, but have a documented solution.

Redesign

5

The migration task requires a redesign or a complete library change, with significant API changes.

Rearchitecture

7

The migration requires a complete rearchitecture of the component or subsystem.

Unknown

13

The migration solution is not known and may need a complete rewrite.

A.3.3. Task category

In addition to the level of effort, you can categorize migration tasks to indicate the severity of the task. The following categories are used to group issues to help prioritize the migration effort.

Mandatory

The task must be completed for a successful migration. If the changes are not made, the resulting application will not build or run successfully. Examples include replacement of proprietary APIs that are not supported in the target platform.

Optional

If the migration task is not completed, the application should work, but the results may not be optimal. If the change is not made at the time of migration, it is recommended to put it on the schedule soon after your migration is completed.

Potential

The task should be examined during the migration process, but there is not enough detailed information to determine if the task is mandatory for the migration to succeed. An example of this would be migrating a third-party proprietary type where there is no directly compatible type.

Information

The task is included to inform you of the existence of certain files. These may need to be examined or modified as part of the modernization effort, but changes are typically not required.

For more information on categorizing tasks, see Using custom rule categories.

A.4. Additional resources

A.4.1. Contributing to the project

To help the Migration Toolkit for Runtimes cover most application constructs and server configurations, including yours, you can help with any of the following items:

  • Send an email to jboss-migration-feedback@redhat.com and let us know what MTR migration rules must cover.

  • Provide example applications to test migration rules.

  • Identify application components and problem areas that might be difficult to migrate:

    • Write a short description of the problem migration areas.

    • Write a brief overview describing how to solve the problem in migration areas.

  • Try Migration Toolkit for Runtimes on your application. Make sure to report any issues you meet.

  • Contribute to the Migration Toolkit for Runtimes rules repository:

    • Write a Migration Toolkit for Runtimes rule to identify or automate a migration process.

    • Create a test for the new rule.

    For more information, see Rules Development Guide.

  • Contribute to the project source code:

    • Create a core rule.

    • Improve MTR performance or efficiency.

Any level of involvement is greatly appreciated!

Use the following resources to learn and contribute to the Migration Toolkit for Runtimes development:

A.4.3. Reporting issues

MTR uses Jira as its issue tracking system. If you encounter an issue executing MTR, submit a Jira issue.


Revised on 2024-11-23 19:18:46 CST