Running the spring-boot-gradle-plugin tests in Eclipse fails on 3.x due to a class cast exception. The cause is that Gradle's internal implementation is being ignored due to it being for SLF4J 1.7.
The following fixes the problem, but I'm not sure if it's the best way to do it.
configurations {
documentation
"testCompileClasspath" {
resolutionStrategy.force("org.slf4j:slf4j-api:1.7.36")
}
}