apache-mime4j: UnstructuredField cannot be cast to ContentTypeField

Question

I have the below groovy code which checks the mime type of a byte [], below apache references are part of apache-mime4j-0.6.jar

import org.apache.james.mime4j.message.Message
import org.apache.james.mime4j.message.Multipart
import org.apache.james.mime4j.message.BodyPart

def processFiledata(filedata){
    Message file = new Message(new ByteArrayInputStream(fileData));
    for (BodyPart part : ((Multipart) file.getBody()).getBodyParts()) {
        if (part.getMimeType().equalsIgnoreCase("text/plain")) { //exception is thrown from this line
            //some logic
        }
}

This code used to work and am not really sure why its throwing below exception now

    java.lang.ClassCastException: org.apache.james.mime4j.field.UnstructuredField cannot be cast to org.apache.james.mime4j.field.ContentTypeField
    at org.apache.james.mime4j.message.Entity.getMimeType(Entity.java:289)

Below is my sample mime message which am reading as ByteArrayInputStream and trying to parse its mime type

MIME-Version: 1.0
Date: Tue, 28 Feb 2017 21:54:17 +1
Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg="SHA256"; boundary="b2971ac914bc41038c7e8412fee3c44c"


--b2971ac914bc41038c7e8412fee3c44c
Content-Type: text/plain; charset=us-ascii

LEDES98BI V2[]
INVOICE_DATE|INVOICE_NUMBER|CLIENT_ID|LAW_FIRM_MATTER_ID|INVOICE_TOTAL|BILLING_START_DATE|BILLING_END_DATE|INVOICE_DESCRIPTION|LINE_ITEM_NUMBER|EXP/FEE/INV_ADJ_TYPE|LINE_ITEM_NUMBER_OF_UNITS|LINE_ITEM_ADJUSTMENT_AMOUNT|LINE_ITEM_TOTAL|LINE_ITEM_DATE|LINE_ITEM_TASK_CODE|LINE_ITEM_EXPENSE_CODE|LINE_ITEM_ACTIVITY_CODE|TIMEKEEPER_ID|LINE_ITEM_DESCRIPTION|LAW_FIRM_ID|LINE_ITEM_UNIT_COST|TIMEKEEPER_NAME|TIMEKEEPER_CLASSIFICATION|CLIENT_MATTER_ID|PO_NUMBER|CLIENT_TAX_ID|MATTER_NAME|INVOICE_TAX_TOTAL|INVOICE_NET_TOTAL|INVOICE_CURRENCY|TIMEKEEPER_LAST_NAME|TIMEKEEPER_FIRST_NAME|ACCOUNT_TYPE|LAW_FIRM_NAME|LAW_FIRM_ADDRESS_1|LAW_FIRM_ADDRESS_2|LAW_FIRM_CITY|LAW_FIRM_STATEorREGION|LAW_FIRM_POSTCODE|LAW_FIRM_COUNTRY|CLIENT_NAME|CLIENT_ADDRESS_1|CLIENT_ADDRESS_2|CLIENT_CITY|CLIENT_STATEorREGION|CLIENT_POSTCODE|CLIENT_COUNTRY|LINE_ITEM_TAX_RATE|LINE_ITEM_TAX_TOTAL|LINE_ITEM_TAX_TYPE|INVOICE_REPORTED_TAX_TOTAL|INVOICE_TAX_CURRENCY[]
19990225|96542|00711|0528|1684.45|19990101|19990131|For services rendered|1|F|2.00|-70|630|19990115|L510||A102|22547|Research Attorney's fees, Set off claim|24-6437381|350|Arnsley, Robert|PARTNR|423-987|77654|76-1235|Merten Merger|694.20|22240.25|GBP|Arnsley|Robert|O|||||||||||||||.16|100.80|VAT|100.80|[]
--b2971ac914bc41038c7e8412fee3c44c
Content-Transfer-Encoding: base64
Content-Type: application/pkcs7-signature; name="smime.p7s"
Content-Disposition: attachment; filename="smime.p7s"

Can someone please help me to fix it?

I see you are using mime4j, and judging by the class name it's the "old" 0.6: see [link to line where the bad class cast occurs](https://github.com/apache/james-mime4j/blob/apache-mime4j-0.6.1/src/main/java/org/apache/james/mime4j/message/Entity.java#L289). You might want to try with 0.7, although there's major API change, it might be less buggy (your issue looks like a mime4j bug to me). You might also want to add a `mime4j` tag to your post, and remove the `apache` one (which is about the irrelevant Apache HTTP server). — Hugues M., May 15 '17 at 16:51
@HuguesMoreau Thanks for the reply, I've updated the library to `0.7.2` and the `Message` class from `0.6` version is converted to an Interface in `0.7.2` and I couldn't find much documentation to create `Message` from byte array, could you please provide and example to create `Message` from `byte array` — OTUser, May 16 '17 at 04:32
So, hummm, that's a no on the example below that shows how to parse a mime-encoded `byte[]` with 0.7.2? I'm afraid the issue you have or had with 0.6 is/was specific to your content. — Hugues M., May 22 '17 at 19:24
@HuguesMoreau Sorry, I've been travelling and havent gotten chance to reply, so your solution isn't working for my data am still getting `UnstructuredField cannot be cast to ContentTypeField `, I've updated the answer with my mime message. can you please check your solution with the given mime message — OTUser, May 22 '17 at 19:43
Well it does work for me, the exact snippet in my answer with the exact snippet of your input, using 0.7.2. Weird. — Hugues M., May 22 '17 at 19:50
OK, so that's probably not an issue with mime4j after all. Maybe check what `fileData` actually contains (make sure you read the right file, with the right encoding, etc). Good luck :) — Hugues M., May 22 '17 at 20:41

Hugues M. · Answer 1 · 2017-05-22T19:51:15.603

That looks like a mime4j bug to me, so as requested in comments where I suggested to upgrade to the very different "new" version 0.7.2 (there is also an upcoming 0.8 in the works), here is an example.

You no longer build a Message object, there are 2 different styles as explained in usage page, I picked the second one because it was clearer to me how to get the mime type of a body part:

def fileInputStream = new FileInputStream("/path/to/message.msg");
def parser = new MimeStreamParser();
parser.setContentHandler(new AbstractContentHandler() {
    void body(BodyDescriptor bd, InputStream is) {
        if ("text/plain".equals(bd.getMimeType())) {
            println("Body: " + is.text);
        }
    }
})
parser.parse(fileInputStream);

If I run that on the following sample message file (courtesy of MSDN):

From: John Doe <example@example.com>
MIME-Version: 1.0
Content-Type: multipart/mixed;
        boundary="XXXXboundary text"

This is a multipart message in MIME format.

--XXXXboundary text 
Content-Type: text/plain

this is the body text

--XXXXboundary text 
Content-Type: text/plain;
Content-Disposition: attachment;
        filename="test.txt"

this is the attachment text

--XXXXboundary text--

I get:

Body: this is the body text

Body: this is the attachment text

Hopefully the bug (if there is one) is fixed in that version. If you still get an issue, we will need to get more information on the structural content of your file.

Edit: with the input you provided, the above works, and gives this:

Body: LEDES98BI V2[]
INVOICE_DATE|INVOICE_NUMBER|CLIENT_ID|LAW_FIRM_MATTER_ID|INVOICE_TOTAL|BILLING_START_DATE|BILLING_END_DATE|INVOICE_DESCRIPTION|LINE_ITEM_NUMBER|EXP/FEE/INV_ADJ_TYPE|LINE_ITEM_NUMBER_OF_UNITS|LINE_ITEM_ADJUSTMENT_AMOUNT|LINE_ITEM_TOTAL|LINE_ITEM_DATE|LINE_ITEM_TASK_CODE|LINE_ITEM_EXPENSE_CODE|LINE_ITEM_ACTIVITY_CODE|TIMEKEEPER_ID|LINE_ITEM_DESCRIPTION|LAW_FIRM_ID|LINE_ITEM_UNIT_COST|TIMEKEEPER_NAME|TIMEKEEPER_CLASSIFICATION|CLIENT_MATTER_ID|PO_NUMBER|CLIENT_TAX_ID|MATTER_NAME|INVOICE_TAX_TOTAL|INVOICE_NET_TOTAL|INVOICE_CURRENCY|TIMEKEEPER_LAST_NAME|TIMEKEEPER_FIRST_NAME|ACCOUNT_TYPE|LAW_FIRM_NAME|LAW_FIRM_ADDRESS_1|LAW_FIRM_ADDRESS_2|LAW_FIRM_CITY|LAW_FIRM_STATEorREGION|LAW_FIRM_POSTCODE|LAW_FIRM_COUNTRY|CLIENT_NAME|CLIENT_ADDRESS_1|CLIENT_ADDRESS_2|CLIENT_CITY|CLIENT_STATEorREGION|CLIENT_POSTCODE|CLIENT_COUNTRY|LINE_ITEM_TAX_RATE|LINE_ITEM_TAX_TOTAL|LINE_ITEM_TAX_TYPE|INVOICE_REPORTED_TAX_TOTAL|INVOICE_TAX_CURRENCY[]
19990225|96542|00711|0528|1684.45|19990101|19990131|For services rendered|1|F|2.00|-70|630|19990115|L510||A102|22547|Research Attorney's fees, Set off claim|24-6437381|350|Arnsley, Robert|PARTNR|423-987|77654|76-1235|Merten Merger|694.20|22240.25|GBP|Arnsley|Robert|O|||||||||||||||.16|100.80|VAT|100.80|[]

apache-mime4j: UnstructuredField cannot be cast to ContentTypeField

1 Answers1