Java SE provides support for a variety of security features and mechanisms, including:
Java Authentication and Authorization Service (JAAS): JAAS is a set of APIs that enable services to authenticate and enforce access controls upon users. JAAS provides a pluggable and extensible framework for programmatic user authentication and authorization. JAAS is a core Java SE API and is an underlying technology for Java EE security mechanisms.
Java Generic Security Services (Java GSS-API): Java GSS-API is a token-based API used to securely exchange messages between communicating applications. The GSS-API offers application programmers uniform access to security services atop a variety of underlying security mechanisms, including Kerberos.
Java Cryptography Extension (JCE): JCE provides a framework and implementations for encryption, key generation and key agreement, and Message Authentication Code (MAC) algorithms. Support for encryption includes symmetric, asymmetric, block, and stream ciphers. Block ciphers operate on groups of bytes while stream ciphers operate on one byte at a time. The software also supports secure streams and sealed objects.
Java Secure Sockets Extension (JSSE): JSSE provides a framework and an implementation for a Java version of the SSL and TLS protocols and includes functionality for data encryption, server authentication, message integrity, and optional client authentication to enable secure Internet communications.
Simple Authentication and Security Layer (SASL): SASL is an Internet standard (RFC 2222) that specifies a protocol for authentication and optional establishment of a security layer between client and server applications. SASL defines how authentication data is to be exchanged but does not itself specify the contents of that data. It is a framework into which specific authentication mechanisms that specify the contents and semantics of the authentication data can fit.
For more information on Java SE security, visit its web page at http://java.sun.com/javase/6/docs/technotes/guides/security/.