Question: I have a table with few fields out of which 2 are of Varchar and Blob type. When I'm retrieving them using queryForMap, I'm getting a map instance with two keys(name of the column). I'm able to cast varchar to String simply but getting ClassCast Exception doing the same with Object.

```
file = new File(System.currentTimeMillis() + (String) map.get("SAMPLE_DOC_FILE_NAME"));
blob = (Blob) map.get("SAMPLE_DOC");

```

My DAO layer method is:

```
public Map<String, Object> getSampleDoc1(String docName) throws SQLException {

    String query = "select form.sample_doc_file_name as SAMPLE_DOC_FILE_NAME, form.sample_document as SAMPLE_DOC from forms form where form.document_name=?";
    return localJdbcTemplateObject.queryForMap(query, docName);
}

```

Exception - `java.lang.ClassCastException: [B cannot be cast to java.sql.Blob`

What can I do to get back this object as Blob?

Answer: 
A `Blob` is just a wrapper for a (possibly large) `byte[]`. What you're getting back from Spring here is the interesting raw data, the `byte[]` (or `B[` in the exception's notation). So, just use that instead, it'll be much easier to work with:

```
byte[] blob = (byte[]) map.get("SAMPLE_DOC");

```
Please check what class it has as this:

```
System.out.println(map.get("SAMPLE_DOC").getClass().getName());

```

then cast to this type, then you can use the API of this type to do something with it.