This tells Gradle to suppress all warnings during compilation. The reason for this is that the framework currently has many warnings, most of which are related to generics usage — particularly raw type warnings — e.g. using Class instead of Class<?> This is an artifact switching to Java 5 in Spring 3. As with the Javadoc warnings mentioned above, committers are encouraged to fix these warnings whenever possible. Once the bulk of them are eliminated, we can switch to -Xlint: all. In the meantime, it just creates unnecessary noise in the build output.