Bug 21183 Class javadoc created during "New Class" operation doesn't fill in variables properly [javadoc] [code manipulation]
If you use the enclosing_type variable in your javadoc comment template, it is not properly filled in when you make a new class (using the New Class dialog). Probably the class should be created, then after creating and saving, javadoc should be added. I suspect the variables don't have valid values yet at the time the javadoc is prepended to the class.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/wizards/NewTypeWizardPage.java
fSuperInterfacesDialogField.setElements(interfacesNames);
		fSuperInterfacesDialogField.setEnabled(canBeModified);
	}
			
	
		
	/**
	 * A hook method that gets called when the package field has changed. The method 
	 * validates the package name and returns the status of the validation. The validation
	 * also updates the package fragment model.
	 * <p>
	 * Subclasses may extend this method to perform their own validation.
	 * </p>
	 * 
	 * @return the status of the validation
	 */
	protected IStatus packageChanged() {
		StatusInfo status= new StatusInfo();
		fPackageDialogField.enableButton(getPackageFragmentRoot() != null);
		
		String packName= getPackageText();
		if (packName.length() > 0) {
			IStatus val= JavaConventions.validatePackageName(packName);
			if (val.getSeverity() == IStatus.ERROR) {
				status.setError(NewWizardMessages.getFormattedString("NewTypeWizardPage.error.InvalidPackageName", val.getMessage())); 
				return status;
			} else if (val.getSeverity() == IStatus.WARNING) {
				status.setWarning(NewWizardMessages.getFormattedString("NewTypeWizardPage.warning.DiscouragedPackageName", val.getMessage())); 
				
			}