Add Support for Custom Headers in SMTP Appender #3704

[sidhantmourya]

While Following the guide for building the project and submitting a PR i was getting the below error

[INFO] Reactor Summary for Apache Log4j BOM 2.26.0-SNAPSHOT:
[INFO]
[INFO] Apache Log4j BOM ................................... SUCCESS [ 20.192 s]
[INFO] Apache Log4j Parent ................................ SUCCESS [ 1.743 s]
[INFO] Apache Log4j API Java 9 support .................... SUCCESS [ 7.196 s]
[INFO] Apache Log4j API ................................... FAILURE [ 1.100 s]
[INFO] Apache Log4j Implementation Java 9 support ......... SKIPPED
[INFO] Apache Log4j Core .................................. SKIPPED
[INFO] Apache Log4j API Tests ............................. SKIPPED
[INFO] Apache Log4j Core Tests ............................ SKIPPED
[INFO] Apache Log4j 1.x Compatibility API ................. SKIPPED
[INFO] Apache Log4j App Server Support .................... SKIPPED
[INFO] Log4j API to SLF4J Adapter ......................... SKIPPED
[INFO] SLF4J 1 Binding for Log4j API ...................... SKIPPED
[INFO] Apache Log4j Cassandra ............................. SKIPPED
[INFO] Apache Log4j fuzz tests ............................ SKIPPED
[INFO] Apache Log4j Core fuzz tests ....................... SKIPPED
[INFO] Apache Log4j Core Integration Tests ................ SKIPPED
[INFO] Apache Log4j CouchDB ............................... SKIPPED
[INFO] Apache Log4j Docker Library ........................ SKIPPED
[INFO] Apache Log4j Streaming Interface ................... SKIPPED
[INFO] Apache Log4j Jakarta JMS ........................... SKIPPED
[INFO] Apache Log4j Jakarta SMTP .......................... SKIPPED
[INFO] Apache Log4j Jakarta Web ........................... SKIPPED
[INFO] Apache Log4j Commons Logging Bridge ................ SKIPPED
[INFO] Apache Log4j JPA ................................... SKIPPED
[INFO] Apache Log4j JDK Platform Logging Adapter .......... SKIPPED
[INFO] Apache Log4j JDBC DBCP 2 ........................... SKIPPED
[INFO] Apache Log4j JUL Adapter ........................... SKIPPED
[INFO] Apache Log4j JSON Template Layout .................. SKIPPED
[INFO] Apache Log4j JSON Template Layout fuzz tests ....... SKIPPED
[INFO] Apache Log4j JSON Template Layout tests ............ SKIPPED
[INFO] Apache Log4j MongoDB 4 ............................. SKIPPED
[INFO] Apache Log4j MongoDB Appender ...................... SKIPPED
[INFO] Apache Log4j to JUL Bridge ......................... SKIPPED
[INFO] Apache Log4j OSGi tests ............................ SKIPPED
[INFO] Apache Log4J Performance Tests ..................... SKIPPED
[INFO] SLF4J 2 Provider for Log4j API ..................... SKIPPED
[INFO] SLF4J 2 Provider for Log4j API fuzz tests .......... SKIPPED
[INFO] Apache Log4j Spring Boot Support ................... SKIPPED
[INFO] Apache Log4j Spring Cloud Config Client Support .... SKIPPED
[INFO] Apache Log4j Web ................................... SKIPPED
[INFO] Apache Log4j Tag Library ........................... SKIPPED
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 30.828 s
[INFO] Finished at: 2026-02-26T22:15:24+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.14.0:compile (default-compile) on project log4j-api: Fatal error compiling: error: release version 8 not supported -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR] mvn -rf :log4j-api

Before this i was getting a API compatibility error, but for some reason i am not seeing it again.

This is my first PR in general and discussion to open source development. So any help is appreciated.
Issue: #3704

[ppkarwasz]

What version of the JDK you are using? It seems that your compiler does not support --release 8. Can you check:

java --version
javac --version
printenv JAVA_HOME

[sidhantmourya]

I'm using java 17.
I was using java 21 but during compilation i started getting errors related to version and it was recommending to use 17

[ppkarwasz]

Hi @sidhantmourya,

Yes, we currently require JDK 17 for the build to ensure that all the builds are reproducible.

Nevertheless, JDK 17 should not have any problems compiling using --release 8, so I would double-check your setup to see if there isn't something wrong. Can you tell us:

• What OS are you using?
• Did you set JAVA_HOME or are you using the version on the system PATH?
• What exact JDK version are you using?

[sidhantmourya]

OS: windows 10

Java home : Amazon coretto 17

Jdk version 17.0.16.8