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/internal/ui/text/javadoc/JavaDocAutoIndentStrategy.java
if (document.getLineOffset(lineIndex) >= partition.getOffset() + partition.getLength())
				return true;
			String string= document.get(line.getOffset(), line.getLength());				
			if (!string.trim().startsWith("*")) 
				return true;
			
			return false;
			
		} catch (BadLocationException e) {
			return false;
		}			
	}
	/*
	 * @see IAutoIndentStrategy#customizeDocumentCommand
	 */
	public void customizeDocumentCommand(IDocument document, DocumentCommand command) {
		try {
			
			if (command.text != null && command.length == 0) {
				String[] lineDelimiters= document.getLegalLineDelimiters();
				int index= TextUtilities.endsWith(lineDelimiters, command.text);
				if (index > -1) {
					
					if (lineDelimiters[index].equals(command.text))
						
						jdocIndentAfterNewLine(document, command);
					return;
				}
			}