How to Diagnose and Fix Maven Compilation AssertionError Using Debug Logs and the javac Compiler

The article addresses a Maven compilation failure that results in an java.lang.AssertionError during the build process, providing step‑by‑step instructions to locate the root cause.

Key error output:

constituent[25]: file:/Users/cuirenzhi/opt/apache-maven-3.6.3/lib/maven-resolver-connector-basic-1.4.1.jar
... (list of JAR files) ...
---------------------------------------------------
Exception in thread "main" java.lang.AssertionError
    at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:155)
    at jdk.compiler/com.sun.tools.javac.util.Assert.check(Assert.java:46)
    at jdk.compiler/com.sun.tools.javac.comp.Modules.enter(Modules.java:247)
    ... (additional stack trace) ...

Step 1: Enable debug logging to obtain more detailed Maven output:

mvn -X

mvn -e

Step 2: If the cause remains unclear, configure the Maven Compiler Plugin to force the use of the standard javac compiler, which often reveals the underlying issue.

<build>
    <plugins>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <forceJavacCompilerUse>true</forceJavacCompilerUse>
            </configuration>
        </plugin>
    </plugins>
</build>

After applying these steps, re‑run the Maven build; the detailed error messages from javac should help pinpoint the exact source of the AssertionError.

References:

Stack Overflow discussion

Apache Maven Compiler JIRA issue MCOMPILER-346