Bug 6672 jar no longer exported after attach source
1206 1. Create a project test. 2. Add a jar (say resources.jar) to the classpath and export the entry 3. Attach source (say resourcessrc.zip) to the jar. Notice, the jar is no longer exported - this information is discarded during the attach source process.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
}
		return null;
	}	
	
		
	private IStatus updatePrefixStatus() {
		StatusInfo status= new StatusInfo();
		
		String prefix= fPrefixField.getText();
		if (prefix.length() == 0) {
			
			return status;
		} else {
			if (!Path.EMPTY.isValidPath(prefix)) {
				status.setError(NewWizardMessages.getString("SourceAttachmentBlock.prefix.error.notvalid")); 
				return status;
			}
			IPath path= new Path(prefix);
			if (fIsVariableEntry) {
				IPath resolvedPath= getResolvedPath(path);
				if (resolvedPath == null) {
					status.setError(NewWizardMessages.getString("SourceAttachmentBlock.prefix.error.varnotexists")); 
					return status;
				}
				if (resolvedPath.getDevice() != null) {
					status.setError(NewWizardMessages.getString("SourceAttachmentBlock.prefix.error.deviceinvar")); 
					return status;
				}
			} else {
				if (path.getDevice() != null) {