...
Weak cryptographic algorithms can be disabled in Java SE 7; see the Java PKI Programmer's Guide, Appendix D: Disabling Cryptographic Algorithms [Oracle 2011a].
Weak cryptographic algorithms may be used in scenarios that specifically call for a breakable cipher. For example, the ROT13 cipher is commonly used on bulletin boards and web sites websites when the purpose of encryption is to protect people from the information rather than protect information from the people.
...