Failed to read file <path>/._<library>.jar - What could be wrong?

[Ingert Doe]

Hi! I want to use the google-api-java-client on the server-side in a
GWT/GAE project but I keep getting strange errors in the console when
I do a test run of my code.

To rule out any other factors, I'v created a new GWT/GAE project (with
the GWT project sample). I added references to the google-api-java-
client (project->properties->java build path-> libraries in eclipse).
I also set the "Source attachment" to the source jars, as mentioned on
the google-api-java-client setup page (http://code.google.com/p/google-
api-java-client/wiki/Setup) and copied the required jars to the war/
lib directory.

I then added the simple youtube example (http://code.google.com/p/
google-api-java-client/wiki/SampleProgram) to my GreetingServiceImpl
method and tweaked it to return the answer of the query to the client.
When I select "Debug as -> Web Application" I get a series of (to me)
strange warnings in the console that I hope someone here can help me
solve.

Notice that all warnings follow a simular pattern:
1) All libraries pertaining to google-api-java-client are affected
(nothing else)
2) The warnings say they can't open ._<library>.jar which is the thing
that confuses me the most, does anyone know what this means?

--- snip ---

[WARN] Failed to read file: /Volumes/PROJECTS/workspace/GApiTest/war/
WEB-INF/lib/._google-api-client-1.4.1-beta.jar
java.util.zip.ZipException: error in opening zip file
at java.util.zip.ZipFile.open(Native Method)
at java.util.zip.ZipFile.<init>(ZipFile.java:127)
at java.util.jar.JarFile.<init>(JarFile.java:135)
at java.util.jar.JarFile.<init>(JarFile.java:99)
at
org.mortbay.jetty.webapp.TagLibConfiguration.configureWebApp(TagLibConfiguration.java:
174)
at
org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:
1247)
at
org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:
517)
at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:
467)
at
org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:
50)
at
org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:
130)
at
org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:
50)
at
org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:
130)
at org.mortbay.jetty.Server.doStart(Server.java:224)
at
org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:
50)
at
com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:
186)
at
com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:
162)
at
com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:
172)
at
com.google.appengine.tools.development.gwt.AppEngineLauncher.start(AppEngineLauncher.java:
119)
at com.google.gwt.dev.DevMode.doStartUpServer(DevMode.java:500)
at com.google.gwt.dev.DevModeBase.startUp(DevModeBase.java:1055)
at com.google.gwt.dev.DevModeBase.run(DevModeBase.java:804)
at com.google.gwt.dev.DevMode.main(DevMode.java:309)

--- snip ---

Warnings continue for all jars in the google-api-java-client package
(including all dependencies)

._google-api-client-extensions-1.4.1-beta.jar
._google-api-client-googleapis-1.4.1-beta.jar
._google-api-client-googleapis-extensions-1.4.1-beta.jar
._commons-codec-1.3.jar
._commons-logging-1.1.1.jar
._gson-1.6.jar
._guava-r09.jar
._httpclient-4.0.3.jar
._httpcore-4.0.1.jar
._jackson-core-asl-1.6.7.jar
._jsr305-1.3.9.jar
._junit-4.8.2.jar
._servlet-api-2.5.jar
._transaction-api-1.1.jar
._xmlParserAPIs-2.6.2.jar
._xpp3-1.1.4c.jar


Note the code actually works fine and I get no errors/warnings in the
console after the app has launched, but these initial warnings confuse
me