This project contains a simple example that demonstrates a bug while encoding an ASN.1 sequence message that contains
an ENUMERATED field.
The message format is the following
David DEFINITIONS ::= BEGIN
MyMessage ::= [APPLICATION 10] IMPLICIT SEQUENCE {
value ENUMERATED { invalid-parameters (0), internal-error (1) },
message PrintableString
}
ENDOnce passed through the jasn1-compiler, it generates
MyMessage.java.
If one tries to do an encode-decode cycle on such a message, an IOException is raised claiming Tag does not match the mandatory sequence element tag.
A closer look reveals that the tag of the embedded ENUMERATED value filed is encoded with number 2
and not 10, as suggested by ASN.1. Consequently,
when trying to decode such a message, an error is thrown.
If we manually change the tag number to 10, the decoding finishes without errors.
Tu run the App.java, issue mvn clean compile exec:java and the output is the following
...
Encoded SEQUENCE{value: 0, message: a} as [106, 6, 2, 1, 0, 19, 1, 97]
Could not decode [106, 6, 2, 1, 0, 19, 1, 97]: Tag does not match the mandatory sequence element tag.
Decoded [106, 6, 10, 1, 0, 19, 1, 97] as SEQUENCE{value: 0, message: a}
....