Currently /usr/share/java/guava.jar ships with 'uses' directives in its manifest's Export-Package declarations :

com.google.common.net;uses:="com.google.common.base,ja
 vax.annotation,com.google.common.hash,com.google.common.io,com.google
 .common.primitives,com.google.common.collect"
 
Eclipse Mylyn has resolution issues because it started requiring guava which brings in javax.annotation from geronimo-annotation while also requiring org.eclipse.core.runtime, which brings in javax.annotation from org.eclipse.osgi.

Bundle was not resolved because of a uses contraint violation.
  org.osgi.service.resolver.ResolutionException: Uses constraint violation. Unable to resolve resource org.eclipse.mylyn.tasks.core [osgi.identity; osgi.identity="org.eclipse.mylyn.tasks.core"; type="osgi.bundle"; version:Version="3.12.0.201405291626"; singleton:="true"] because it is exposed to package 'javax.annotation' from resources org.eclipse.osgi [osgi.identity; osgi.identity="org.eclipse.osgi"; type="osgi.bundle"; version:Version="3.10.0.v20140603-1713"; singleton:="true"] and org.apache.geronimo.specs.geronimo-annotation_1.1_spec [osgi.identity; singleton="true"; osgi.identity="org.apache.geronimo.specs.geronimo-annotation_1.1_spec"; type="osgi.bundle"; version:Version="1.0.0"; singleton:="true"] via two dependency chains.

Chain 1:
  org.eclipse.mylyn.tasks.core [osgi.identity; osgi.identity="org.eclipse.mylyn.tasks.core"; type="osgi.bundle"; version:Version="3.12.0.201405291626"; singleton:="true"]
    require: (osgi.wiring.bundle=org.eclipse.core.runtime)
     |
    provide: osgi.wiring.bundle: org.eclipse.core.runtime
  org.eclipse.osgi [osgi.identity; osgi.identity="org.eclipse.osgi"; type="osgi.bundle"; version:Version="3.10.0.v20140603-1713"; singleton:="true"]

Chain 2:
  org.eclipse.mylyn.tasks.core [osgi.identity; osgi.identity="org.eclipse.mylyn.tasks.core"; type="osgi.bundle"; version:Version="3.12.0.201405291626"; singleton:="true"]
    require: (&(osgi.wiring.bundle=com.google.guava)(bundle-version>=15.0.0))
     |
    provide: osgi.wiring.bundle; bundle-version:Version="15.0.0"; osgi.wiring.bundle="com.google.guava"
  com.google.guava [osgi.identity; osgi.identity="com.google.guava"; type="osgi.bundle"; version:Version="15.0.0"]
    import: (osgi.wiring.package=javax.annotation)
     |
    export: osgi.wiring.package: javax.annotation
  org.apache.geronimo.specs.geronimo-annotation_1.1_spec [osgi.identity; singleton="true"; osgi.identity="org.apache.geronimo.specs.geronimo-annotation_1.1_spec"; type="osgi.bundle"; version:Version="1.0.0"; singleton:="true"]
  
I'm aware that this package is in the process of being updated from 15 to 17 in rawhide, so I'm fine with waiting until the FTBFS + update are resolved, and fixing this afterwards.