无论我的代码是java，都只为Maven设置JAVA_HOME

Question

I am running different java projects. Understanding that changing java_home system environment each time I switch between them is a bad idea, I'm starting to set JAVA_HOME specifically for each one of them independently . When I set JAVA_HOME for maven (version 2) runtime (the java maven uses to run, being a java application)? To my understanding, JAVA_HOME for maven should not affect how my code is compiled and run (which are supposed to be configured using maven-compiler-plugin source and target). Right?

When I set JAVA_HOME in mvn.bat :

@REM Maven2 Start Up Batch script
set JAVA_HOME=C:\dev\tools\jdk-1.6

And my maven-compiler-plugin is configured this way:

<plugin>
  <artifactId>maven-compiler-plugin</artifactId>
  <configuration>
    <source>1.7</source>
    <target>1.7</target>
  </configuration>
</plugin>

I receive this error:

[ERROR] BUILD ERROR
[INFO] --------------------------------------
[INFO] Fatal error compiling
Embedded error: invalid target release: 1.7

Why does JAVA_HOME specified for maven runtime affect my code compilation? How to separate between the two?

Answer 1

Maven will use the JRE specified in JAVA_HOME By default it will use the JDK from the same folder for compiling .java files

However you can change it in maven-compile-plugin configuration

<project>
  [...]
  <build>
    [...]
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.5.1</version>
        <configuration>
          <verbose>true</verbose>
          <fork>true</fork>
          <executable><!-- path-to-javac --></executable>
          <compilerVersion>1.3</compilerVersion>
        </configuration>
      </plugin>
    </plugins>
    [...]
  </build>
  [...]
</project>