The Java Tutorials have been written for JDK 8.Java教程是为JDK 8编写的。Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.本页中描述的示例和实践没有利用后续版本中引入的改进，并且可能使用不再可用的技术。See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.有关Java SE 9及其后续版本中更新的语言特性的摘要，请参阅Java语言更改。
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.有关所有JDK版本的新功能、增强功能以及已删除或不推荐的选项的信息，请参阅JDK发行说明。
Different versions of the LDAP support different types of authentication. The LDAP v2 defines three types of authentication: anonymous, simple (clear-text password), and Kerberos v4.
The LDAP v3 supports anonymous, simple, and SASL authentication. SASL is the Simple Authentication and Security Layer ( RFC 2222). It specifies a challenge-response protocol in which data is exchanged between the client and the server for the purposes of authentication and establishment of a security layer on which to carry out subsequent communication. By using SASL, the LDAP can support any type of authentication agreed upon by the LDAP client and server.
This lesson contains descriptions of how to authenticate by using Anonymous, Simple, and SASL authentication.
The authentication mechanism is specified by using the Context.SECURITY_AUTHENTICATION environment property. The property may have one of the following values.
| Property Name | Property Value |
|---|---|
| sasl_mech | A space-separated list of SASL mechanism names. Use one of the SASL mechanisms listed (such as "CRAM-MD5" means to use the CRAM-MD5 SASL mechanism described in RFC 2195). |
| none | Use no authentication (anonymous) |
| simple | Use weak authentication (clear-text password) |
If the client does not specify any authentication environment properties, then the default authentication mechanism is "none". The client will then be treated as an anonymous client.
If the client specifies authentication information without explicitly specifying the Context.SECURITY_AUTHENTICATION property, then the default authentication mechanism is "simple".