Bug 53201 NPE when re-running newly generated javadoc.xml
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javadocexport/JavadocWriter.java
if (str.length() > 0) 
			xmlJavadocDesc.setAttribute(store.EXTRAOPTIONS, str);
	}
	private String toSeparatedList(List packages) {
		StringBuffer buf= new StringBuffer();
		Iterator iter= packages.iterator();
		int nAdded= 0;
		while (iter.hasNext()) {
			if (nAdded > 0) {
				buf.append(',');
			}
			nAdded++;
			String curr= (String) iter.next();
			buf.append(curr);
		}
		return buf.toString();
	}
	private String booleanToString(boolean bool) {
		if (bool)
			return "true"; 
		else
			return "false"; 
	}
	public void close() throws IOException {
		if (fOutputStream != null) {
			fOutputStream.close();
		}
	}
}