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
/**
	 * Returns the text of the enclosing type input field.
	 * 
	 * @return the text of the enclosing type input field
	 */	
	public String getEnclosingTypeText() {
		return fEnclosingTypeDialogField.getText();
	}	
	
	
	/**
	 * Returns the package fragment corresponding to the current input.
	 * 
	 * @return a package fragement or <code>null</code> if the input 
	 * could not be resolved.
	 */
	public IPackageFragment getPackageFragment() {
		if (!isEnclosingTypeSelected()) {
			return fCurrPackage;
		} else {
			if (fCurrEnclosingType != null) {
				return fCurrEnclosingType.getPackageFragment();
			}
		}
		return null;
	}
	
	/**
	 * Sets the package fragment to the given value. The method updates the model 
	 * and the text of the control.