Messages and Parts - JavaMail API - page 63

The getContentID() method returns a string that uniquely identifies this part as given
by the part's Content-ID: field. A typical ID might look like < Pine.LNX.
[e-mail] > . It returns null if the part doesn't have a
content ID:
public String getContentID () throws MessagingException
IllegalWriteException , IllegalStateException
The getContentLanguage() method returns the value of the Content-language: header.
This is a comma-separated list of two (or more) letter abbreviations for languages, as
defined by RFC 1766. For example, English is “en” and French is “fr”. It returns null if
the part doesn't have a Content-language: header.
public String [] getContentLanguage () throws MessagingException
There's also a setContentLanguage() method that you might use when sending a mes‐
sage:
public void setContentLanguage ( String [] languages ) throws
MessagingException , IllegalWriteException , IllegalStateException
Finally, the two setText() methods set the content of the part with the MIME type
text/plain . The second setText() method also lets you specify the character set—for
example, us-ascii or ISO 8859-1:
public void setText ( String text ) throws MessagingException
public void setText ( String text , String charset )
throws MessagingException
public void setText ( String text , String charset , String subtype )
throws MessagingException
In practice, a number of mail systems and libraries, especially Japanese ones, do not
correctly implement every detail of the relevant specifications. Consequently the Java‐
Mail API recognizes a number of system properties that control exactly how strictly
various rules are followed. Table 7-1 lists the various system properties that control
MIME parsing. With a couple of exceptions the default values provide standards con‐
formant behavior, and changing these breaks conformance to work better with some
mail agents encountered in the wild.