Maven add a folder or jar file into current classpath

Question

I am using maven-compile plugin to compile classes  Now I would like to add one jar file into the current classpath  That file stays in another location  let s say c  jars abc jar   I prefer to leave this file here   How can I do that   If I use classpath in the argument    lt configuration gt    lt compilerArguments gt     lt classpath gt c  jars abc jar lt  classpath gt    lt  compilerArguments gt   lt  configuration gt    it will not work because it will override the current classpath  that includes all the dependencies   Please help me

User · Answer

From docs and example it is not clear that classpath manipulation is not allowed.

<configuration>
 <compilerArgs>
  <arg>classpath=${basedir}/lib/bad.jar</arg>
 </compilerArgs>
</configuration>

But see Java docs (also https://www.cis.upenn.edu/~bcpierce/courses/629/jdkdocs/tooldocs/solaris/javac.html)

-classpath path Specifies the path javac uses to look up classes needed to run javac or being referenced by other classes you are compiling. Overrides the default or the CLASSPATH environment variable if it is set.

Maybe it is possible to get current classpath and extend it,
see in maven, how output the classpath being used?

    <properties>
      <cpfile>cp.txt</cpfile>
    </properties>

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-dependency-plugin</artifactId>
    <version>2.9</version>
    <executions>
      <execution>
        <id>build-classpath</id>
        <phase>generate-sources</phase>
        <goals>
          <goal>build-classpath</goal>
        </goals>
        <configuration>
          <outputFile>${cpfile}</outputFile>
        </configuration>
      </execution>
    </executions>
  </plugin>

Read file (Read a file into a Maven property)

<plugin>
  <groupId>org.codehaus.gmaven</groupId>
  <artifactId>gmaven-plugin</artifactId>
  <version>1.4</version>
  <executions>
    <execution>
      <phase>generate-resources</phase>
      <goals>
        <goal>execute</goal>
      </goals>
      <configuration>
        <source>
          def file = new File(project.properties.cpfile)
          project.properties.cp = file.getText()
        </source>
      </configuration>
    </execution>
  </executions>
</plugin>

and finally

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.6.1</version>
    <configuration>
      <compilerArgs>
         <arg>classpath=${cp}:${basedir}/lib/bad.jar</arg>
      </compilerArgs>
    </configuration>
   </plugin>

User · Answer

This might have been asked before  See Can I add jars to maven 2 build classpath without installing them   In a nutshell  include your jar as dependency with system scope  This requires specifying the absolute path to the jar    See also http   maven apache org guides introduction introduction-to-dependency-mechanism html

User · Answer

The classpath setting of the compiler plugin are two args  Changed it like this and it worked for me   lt plugin gt   lt groupId gt org apache maven plugins lt  groupId gt   lt artifactId gt maven-compiler-plugin lt  artifactId gt   lt version gt 3 6 1 lt  version gt   lt configuration gt     lt compilerArgs gt        lt arg gt -cp lt  arg gt        lt arg gt   cp    basedir  lib bad jar lt  arg gt     lt  compilerArgs gt   lt  configuration gt       I used the gmavenplus-plugin to read the path and create the property  cp          lt plugin gt       lt  --       Use Groovy to read classpath and store into       file named value of property  lt cpfile gt         In second step use Groovy to read the contents of       the file into a new property named  lt cp gt         In the compiler plugin this is used to create a       valid classpath     -- gt       lt groupId gt org codehaus gmavenplus lt  groupId gt       lt artifactId gt gmavenplus-plugin lt  artifactId gt       lt version gt 1 12 0 lt  version gt       lt dependencies gt         lt dependency gt           lt groupId gt org codehaus groovy lt  groupId gt           lt artifactId gt groovy-all lt  artifactId gt           lt  -- any version of Groovy   gt   1 5 0 should work here -- gt           lt version gt 3 0 6 lt  version gt           lt type gt pom lt  type gt           lt scope gt runtime lt  scope gt         lt  dependency gt       lt  dependencies gt       lt executions gt         lt execution gt           lt id gt read-classpath lt  id gt           lt phase gt validate lt  phase gt           lt goals gt             lt goal gt execute lt  goal gt           lt  goals gt         lt  execution gt        lt  executions gt       lt configuration gt         lt scripts gt           lt script gt  lt   CDATA                  def file   new File project properties cpfile                     create a new property named  cp                    project properties cp   file getText                   println   lt  lt  lt  Retrieving classpath into new property named  lt cp gt   gt  gt  gt                   println  cp       project properties cp                  gt  lt  script gt         lt  scripts gt       lt  configuration gt     lt  plugin gt

[maven-2] Maven: add a folder or jar file into current classpath

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