This can be triggered by incompatibilities between the AWS SDK on the classpath and the version with which Hadoop was compiled.

The AWS SDK JARs change their signature between releases often, so the only way to safely update the AWS SDK version is to recompile Hadoop against the later version.

There is nothing the Hadoop team can do here; if you get this problem, then you are on your own. The Hadoop developer team did look at using reflection to bind to the SDK, but there were too many changes between versions for this to work reliably. All it did was postpone version compatibility problems until the specific codepaths were executed at runtime. This was actually a backward step in terms of fast detection of compatibility problems.