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Unable to compile simple Java 10 / Java 11 project with Maven

由 会有一股神秘感。 提交于 2019-11-25 21:39:06
ZhekaKozlov

UPDATE

The answer is now obsolete. See this answer.

maven-compiler-plugin depends on the old version of ASM which does not support Java 10 (and Java 11) yet. However, it is possible to explicitly specify the right version of ASM:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.7.0</version>
    <configuration>
        <release>10</release>
    </configuration>
    <dependencies>
        <dependency>
            <groupId>org.ow2.asm</groupId>
            <artifactId>asm</artifactId>
            <version>6.2</version> <!-- Use newer version of ASM -->
        </dependency>
    </dependencies>
</plugin>

You can find the latest at https://search.maven.org/search?q=g:org.ow2.asm%20AND%20a:asm&core=gav

Alternatively, as of 30Jul, 2018 to fix the above issue, one can configure the java version used within maven to any up to JDK/11 and make use of the maven-compiler-plugin:3.8.0 to specify a release of either 9,10,11 without any explicit dependencies.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.8.0</version>
    <configuration>
        <release>11</release>  <!--or <release>10</release>-->
    </configuration>
</plugin>

Note:- The default value for source/target has been lifted from 1.5 to 1.6 with this version. -- release notes.

Edit [30.12.2018]

In fact, you can make use of the same version of maven-compiler-plugin while compiling the code against JDK/12 as well.

More details and a sample configuration in how to Compile a JDK12 preview feature with Maven.

Boosting your maven-compiler-plugin to 3.8.0 seems to be necessary but not sufficient. If you're still having problems, you should also make sure your JAVA_HOME environment variable is set to Java 10 (or 11) if you're running from the command line. (The error message you get won't tell you this.) Or if you're running from an IDE, you need to make sure it is set to run maven with your current JDK.

It might not exactly be the same error, but I had a similar one.

Check Maven Java Version

Since Maven is also runnig with Java, check first with which version your Maven is running on:

mvn --version | grep Java

It returns:

Java version 1.8.0_151, vendor: Oracle Corporation, runtime: C:\tools\jdk\openjdk1.8

Incompatible version

Here above my maven is running with Java Version 1.8.0_151. So even if I specify maven to compile with Java 11:

<properties>
    <java.version>11</java.version>
    <maven.compiler.source>${java.version}</maven.compiler.source>
    <maven.compiler.target>${java.version}</maven.compiler.target>
</properties>

It will logically print out this error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project efa-example-commons-task: Fatal error compiling: invalid target release: 11 -> [Help 1]

How to set specific java version to Maven

The logical thing to do is to set a higher Java Version to Maven (e.g. Java version 11 instead 1.8).

Maven make use of the environment variable JAVA_HOME to find the Java Version to run. So change this variable to the JDK you want to compile against (e.g. OpenJDK 11).

Sanity check

Then run again mvn --version to make sure the configuration has been taken care of:

λ mvn --version | grep Java Java version: 11.0.2, vendor: Oracle Corporation, runtime: C:\tools\jdk\openjdk11

Which is much better and correct to compile code written with the Java 11 specifications.

Specify maven.compiler.source and target versions.

1) Maven version which supports jdk you use. In my case JDK 11 and maven 3.6.0.

2) pom.xml

<properties>
    <maven.compiler.source>11</maven.compiler.source>
    <maven.compiler.target>11</maven.compiler.target>
</properties>

As an alternative, you can fully specify maven compiler plugin. See previous answers. It is shorter in my example :)

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.0</version>
            <configuration>
                <release>11</release>
            </configuration>
        </plugin>
    </plugins>
</build>

3) rebuild the project to avoid compile errors in your IDE.

4) If it still does not work. In Intellij Idea I prefer using terminal instead of using terminal from OS. Then in Idea go to file -> settings -> build tools -> maven. I work with maven I downloaded from apache (by default Idea uses bundled maven). Restart Idea then and run mvn clean install again. Also make sure you have correct Path, MAVEN_HOME, JAVA_HOME environment variables.

I also saw this one-liner, but it does not work.

<maven.compiler.release>11</maven.compiler.release>
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