Why cannot overwrite a KeyEntry with a TrustCertEntry?

[Weijun Wang]

Hi All

The KeyStore::setCertificateEntry has

* @exception KeyStoreException if the keystore has not been initialized,
* or the given alias already exists and does not identify an
* entry containing a trusted certificate,
* or this operation fails for some other reason.

which means you cannot overwrite a KeyEntry with a TrustCertEntry. While 
setKeyEntry allows a TrustCertEntry been overwritten by a KeyEntry.

This has been true from the beginning, but why?

On the other hand, setEntry mentions no restriction, although the 
current implementations (jks, pkcs12) fail when overwriting a KeyEntry 
with a TrustCertEntry.

Thanks
Max