id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
1390	NullPointerException in HibernateDocumentDAO.findTags() when firstLetter is null	Blucecio		"A NullPointerException was detected in the application log while processing requests to the `TagsData` servlet.

The exception occurs in `HibernateDocumentDAO.findTags()` at line 672, where `String.toLowerCase()` is invoked on a null `firstLetter` parameter.

**Error details:**
```text
java.lang.NullPointerException:
Cannot invoke ""String.toLowerCase()""
because ""firstLetter"" is null

at com.logicaldoc.core.document.HibernateDocumentDAO.findTags(HibernateDocumentDAO.java:672)
at com.logicaldoc.web.data.TagsDataServlet.buildTagsMap(TagsDataServlet.java:130)
at com.logicaldoc.web.data.TagsDataServlet.service(TagsDataServlet.java:51)
```

The exception was logged twice within approximately one second.

**Observed behavior:**

No visible malfunction was noticed while using LogicalDOC. The application appears to operate normally, and the issue was discovered only by inspecting the server logs.

**Expected behavior:**

The tag retrieval process should handle a null `firstLetter` parameter gracefully, without throwing an exception.

**Suggested investigation:**

Verify whether `HibernateDocumentDAO.findTags()` properly handles null values for the `firstLetter` parameter and whether `TagsDataServlet` can invoke this method without providing a valid value.

The complete stack trace is attached."	bug	new	minor	9.3.2	User Interface	9.3.1