This issue started happening since 1.446+ (meaning, 446, 447, 448). Apparently either jenkins core or some plugin is using slf4j, but neither Jenkins, nor the plugin ships with any slf4 implementations, resulting the in following stack trace on startup...

Failed to instantiate SLF4J LoggerFactory
Reported exception:
java.lang.NoClassDefFoundError: org.slf4j.impl.StaticLoggerBinder
at org.slf4j.LoggerFactory.bind(LoggerFactory.java:121)
at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.javCaused by: java.lang.ClassNotFoundException: org.slf4j.impl.StaticLoggerBinder
at java.lang.ClassNotFoundException.<init>(ClassNotFoundException.java:77)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1524)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1491)
... 22 more

I was able to get Jenkins to start fine by manually downloading the slf4j-simple directly from maven and putting it into WEB-INF/lib... but, without that file, Jenkins is 100% unusable.

http://repo2.maven.org/maven2/org/slf4j/slf4j-simple/1.6.1/slf4j-simple-1.6.1.jar