Null Pointer Exception when using Generate deploy/rmic in WSAD

Exception::

at java.lang.NullPointerException.(NullPointerException.java)
at com.ibm.etools.java.plugin.ProjectUtilities.collectClasspathURLs(ProjectUtilities.java)
at com.ibm.etools.ejbdeploy.plugin.EJBDeployOperation.run(EJBDeployOperation.java:1255)
at com.ibm.etools.ejbdeploy.ui.plugin.DeployRMICBeansOperation.
generateDeployCode(DeployRMICBeansOperation.java:304)

Cause::
This problem occurs when we build/generate/deploy rmic code for
EJB projects without building the projects that need to be pre-built.

Solution::
Build projects based on their dependence hierarchy we wont get this error.