Though Guava can provide an easier API to do some common operations, there can be dependency convergence problems when different versions of Guava are used between different dependencies.
Guava also has the tendency to deprecate APIs between versions.
Primarily to avoid situations like this http://stackoverflow.com/questions/28368289/use-multiple-guava-versions-in-same-maven-project
Though Guava can provide an easier API to do some common operations, there can be dependency convergence problems when different versions of Guava are used between different dependencies.
Guava also has the tendency to deprecate APIs between versions.
Primarily to avoid situations like this http://stackoverflow.com/questions/28368289/use-multiple-guava-versions-in-same-maven-project