What do we meant by "Unresolved requirement: Import-Package: com.google.common.collect_ [Sanitized]" in liferay 7.2 - maven

Question

I am creating a hook in liferay 7.2 but unfortunately when I deploy it.I come across this error. I had tried increasing version of "com.google.collections" dependency and also tried adding guauva
a dependency but nothing seems to resolve this error.
My dependencies in Pom.xml is as such:
<dependencies>
<dependency>
<groupId>com.liferay.portal</groupId>
<artifactId>com.liferay.portal.kernel</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.osgi</groupId>
<artifactId>org.osgi.service.component.annotations</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.google.collections</groupId>
<artifactId>google-collections</artifactId>
<version>1.0-rc2</version>
</dependency>
<dependency>
<groupId>org.osgi</groupId>
<artifactId>osgi.cmpn</artifactId>
<version>6.0.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.1.2</version>
<configuration>
<archive>
<manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>biz.aQute.bnd</groupId>
<artifactId>bnd-maven-plugin</artifactId>
<version>4.3.0</version>
<executions>
<execution>
<goals>
<goal>bnd-process</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>biz.aQute.bnd</groupId>
<artifactId>biz.aQute.bndlib</artifactId>
<version>4.3.0</version>
</dependency>
<dependency>
<groupId>com.liferay</groupId>
<artifactId>com.liferay.ant.bnd</artifactId>
<version>3.2.6</version>
</dependency>
</dependencies>
Error :
org.osgi.framework.BundleException: Could not resolve module: com.allen.portal.hook [1272]_ Unresolved requirement: Import-Package: com.google.common.collect_ [Sanitized]
at org.eclipse.osgi.container.Module.start(Module.java:444)
at org.eclipse.osgi.internal.framework.EquinoxBundle.start(EquinoxBundle.java:428)
at com.liferay.portal.file.install.internal.DirectoryWatcher._startBundle(DirectoryWatcher.java:1106)
at com.liferay.portal.file.install.internal.DirectoryWatcher._startBundles(DirectoryWatcher.java:1139)
at com.liferay.portal.file.install.internal.DirectoryWatcher._process(DirectoryWatcher.java:1001)
at com.liferay.portal.file.install.internal.DirectoryWatcher.run(DirectoryWatcher.java:313)
If you have any ways to resolve this error, please help me out

Answer 1

Unrelated: You're using an rc2 version released in October 2009, when a release was made in December 2009? Seriously?
It looks like you're building an OSGi module, which compiles fine (because you provide the dependency). However, that does not mean that the google collections code ends up in your jar as well. The runtime expects to find it though - and as Google collections is not an OSGi bundle itself, you'll have several choices:
repackage it as OSGi bundle (and deploy it to the runtime) (or find someone who did it already)
repackage it within your own bundle
use a different implementation. Chances are that collections utility code from 2009 has found its way into more current implementations and is no longer necessary.
In short: In one way or another, you'll need to make your dependencies available at runtime. Either by fattening your own bundle (but be careful: You can't pass those collections around to other bundles if they bring their own implementation) or by relying on the implementation being available to the runtime.
The third alternative is to switch to an implementation where it's easier to make it available at runtime, preferably as OSGi bundle.