There is a mistake in the requirement above. Correcting the input structure and output structure
Input structure
<MAT>
<doc type>pdf</doc type
<subnumber>1234</subnumber>
<id>45ABC<id>
<matno>ABCD</matno>
<file> 0..unbounded
<file_name>file1.pdf<file_name> ----->name of the first file
<file_id>2y7hsjsj</file_id> -------------->unique id of the first file
<file_type>pdf</file_type> --------------->type of the file
</file>
<file>
<file_name>file2.xml<file_name> ------------->name of the second file
<file_id>8mnk9<file_id> -----------------unique id of the second file
<file_type>xml<file_type> ------------------>type of the file
</file>
<file>
<file_name>file3.xml> ----------------->name of the third file
<file_id>e783kj3k3</file_id ---------------->unique id of the third file
<file_type>xml</file_type> -------------->type of the file
</file>
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</MAT>
Output structure
<MAT>
<doc type>pdf</doc type
<subnumber>1234</subnumber>
<id>45ABC<id>
<matno>ABCD</matno>
<file> 0..unbounded
<file_content>file1.pdf<file_name> ----->byte array content of the first file
<file_id>2y7hsjsj</file_id> -------------->unique id of the first file
<file_type>pdf</file_type> --------------->type of the file
</file>
<file>
<file_content>file2.xml<file_name> ------------->byte array content of the second file
<file_id>8mnk9<file_id> -----------------unique id of the second file
<file_type>xml</file_type> ---------------------->type of the file
</file>
<file>
<file_content>file3.xml> ----------------->byte array content of the third file
<file_id>e783kj3k3</file_id ---------------->unique id of the third file
<file_type>xml<file_type> --------------->type of the file
</file>
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------------------------
---------------------
</MAT>
thx
mike