Focused crawls are collections of frequently-updated webcrawl data from narrow (as opposed to broad or wide) web crawls, often focused on a single domain or subdomain.
Apache Log4j 2 is an upgrade to Log4j that provides significant improvements over its predecessor, Log4j 1.x, and provides many of the improvements available in Logback while fixing some inherent problems in Logback's architecture.
Because first JDK 1.8 release was published 5.5 years ago and now I don't know any libraries, which work incorrect with JDK 1.8, maybe you can migrate your adapter to JDK 1.8?
If you do this, you could use Java 8 features, like java.time and could migrate to Spring Boot 2.2.0
Graylog Extended Log Format (GELF) implementation in Java for all major logging frameworks: log4j, log4j2, java.util.logging, logback, JBossAS7 and WildFly 8-12
Because first JDK 1.8 release was published 5.5 years ago and now I don't know any libraries, which work incorrect with JDK 1.8, maybe you can migrate your adapter to JDK 1.8?
If you do this, you could use Java 8 features, like java.time and could migrate to Spring Boot 2.2.0