Upgrading RS Gateway Extensions

In most extensions, code changes are needed because of API changes in the new versions of Spring Boot. Refer to the following additional third-party documentation for more information:

• The discussion about preparing for 6.0 in the Spring Security documentation. Specifically refer to the servlet migration topics.
• The Spring Boot 3.0 Migration Guide in GitHub.
• The discussion about Spring Boot logging in the Spring Boot documentation.

In some extensions, you might have to identify incompatible packages that were brought in because of third-party dependencies. For example, you might see a log4j error on start-up:

// error
Exception in thread "main" java.lang.NoSuchMethodError: org.apache.logging.slf4j.Log4jLoggerFactory: method 'void <init>()' not found

In this situation, update the pom.xml file to exclude the dependency like this:

// pom.xml
  <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-log4j2</artifactId>
     <exclusions>
       <exclusion>
         <groupId>org.apache.logging.log4j</groupId>
         <artifactId>log4j-slf4j2-impl</artifactId>
       </exclusion>
     </exclusions>
  </dependency>

Non-Spring versions that were specified in your pom.xml file could bring in older and non-compatible versions of other dependencies. In this case, use the following Maven command to generate a dependency tree to determine how a dependency was brought in:

mvn -DoutputFile=tree.txt dependency:tree

You might have errors such as the following:

log4j:WARN No appenders could be found for logger (org.apache.htrace.core.Tracer).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info. 

If the transitive dependencies are not logged, you can try to fix the issue temporarily by specifying the compatible versions of the logging dependencies in your pom.xml file. For example:

<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.23.1</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.23.1</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j-impl</artifactId>
    <version>2.23.1</version>
</dependency>