<body> <h1>Overview</h1> <p>Smack is a library for client-to-server XMPP connections to perform real-time communications and data exchange. This includes, but is not limited to, instant messaging and group chat. More generically speaking, it allows you to easily exchange data in various ways: For example fire-and-forget, publish-subscribe, between human and non-human endpoints. The use cases include M2M, IoT, and many more.</p> <p>Smack is a pure Java library, open-source and highly modular. It runs on Android and Java SE. The API strives to be easy to use but yet powerful.</p> <h2>Key Advantages</h2> Smack is extremely simple to use, yet provides a powerful API. Sending a text message to a user can be accomplished in only a few lines of code. <pre>{@code AbstractXMPPConnection connection = new XMPPTCPConnection("mtucker", "password", "jabber.org"); connection.connect().login(); Message message = connection.getStanzaFactory() .buildMessageStanza() .to("jsmith@igniterealtime.org") .setBody("Howdy! How are you?") .build(); connection.sendStanza(message); connection.disconnect(); }</pre> <p>Smack doesn't force you to code at the protcol level of XMPP. The library provides intelligent higher level constructs, often called {@link org.jivesoftware.smack.Manager}, which let you program more efficiently. Other examples of those constructs are the Chat and Roster classes.</p> <p>Smack comes with APIs for easy machine-to-machine communication. You can set any number of properties on each message, including properties that are Java objects.</p> <h2>License</h2> <p>Smack is open-source and most parts are under the Apache License 2.0, which means you can incorporate Smack into your commercial or non-commercial applications. Some parts of Smack may be under a different open-source license. Please refer to the individual subprojects for their license statement.</p> <p>Note that the Apache License 2.0 requires that the contents of a NOICE text file are shown "…within a display generated by the Derivative Works, if and wherever such third-party notices normally appear.". Smack comes with such a NOTICE file. The content of Smack's NOTICE file can conveniently be retrieved using {@link org.jivesoftware.smack.Smack#getNoticeStream}.</p> <h2>About XMPP</h2> <p>XMPP (eXtensible Messaging and Presence Protocol) is an open protocol standardized by the <a href="https://ietf.org/">Internet Engineering Task Force (IETF)</a> and supported and extended by the <a href="https://www.xmpp.org/">XMPP Standards Foundation (XSF)</a>.</p> <h2>Smack Modules</h2> <p>Smack is meant to be easily embedded into any existing Java application. The library ships as several modules to provide more flexibility over which features applications require.</p> <ul> <li>smack-core -- provides core XMPP functionality. All XMPP features that are part of the XMPP RFCs are included.</li> <li>smack-im -- provides functionality defined in RFC 6121 (XMPP-IM), like the Roster.</li> <li>{@link org.jivesoftware.smack.tcp smack-tcp} -- support for XMPP over TCP. Includes XMPPTCPConnection class, which you usually want to use</li> <li>smack-extensions -- support for many of the extensions (XEPs) defined by the XMPP Standards Foundation, including multi-user chat, file transfer, user search, etc. The extensions are documented in the [extensions manual](extensions/index.md).</li> <li>smack-experimental -- support for experimental extensions (XEPs) defined by the XMPP Standards Foundation. The API and functionality of those extensions should be considered as unstable.</li> <li>smack-legacy -- support for legacy extensions (XEPs) defined by the XMPP Standards Foundation. <li>smack-bosh -- support for BOSH (XEP-0124). This code should be considered as beta.</li> <li>smack-resolver-minidns -- support for resolving DNS SRV records with the help of <a href="https://minidns.org">MiniDNS</a>. Ideal for platforms that do not support the javax.naming API. Also supports [DNSSEC](dnssec.md) TODO: Fix link.</li> <li>smack-resolver-dnsjava -- support for resolving DNS SRV records with the help of dnsjava.</li> <li>smack-resolver-javax -- support for resolving DNS SRV records with the javax namespace API.</li> <li>smack-debug -- an enhanced GUI debugger for protocol traffic. It will automatically be used when found in the classpath and when [debugging](debugging.md) is enabled.</li> </ul> <h2>Main API Entry Points</h2> <ul> <li>{@link org.jivesoftware.smack.XMPPConnection}</li> <li>{@link org.jivesoftware.smack.tcp.XMPPTCPConnection}</li> <li>{@link org.jivesoftware.smack.roster.Roster}</li> <!-- <li>{@link org.jivesoftware.smack.chat2.Chat}</li> --> <!-- More form index.md --> </ul> <h2>Smack Extensions</h2> <p> Since the X in XMPP stands for eXstensible, Smack comes with many built-in extensions for XMPP. Click </p> <blockquote><b>{@link org.jivesoftware.smackx}</b></blockquote> <p> for an overview of all supporteted XMPP extensions of Smack. </p> Some selected extensions are <ul> <li>{@link org.jivesoftware.smackx.muc.MultiUserChat Multi-User Chat (XEP-0045)}</li> <li>{@link org.jivesoftware.smackx.carbons.CarbonManager Message Carbons (XEP-0289)}</li> <li>{@link org.jivesoftware.smackx.omemo OMEMO (XEP-0384)}</li> <!-- <li>{@link org.jivesoftware.smack.chat2.Chat}</li> --> <!-- More form index.md --> </ul> <h2>Configuration</h2> <p>Smack has an initialization process that involves 2 phases.</p> <ul> <li>Initializing system properties - Initializing all the system properties accessible through the class **SmackConfiguration**. These properties are retrieved by the _getXXX_ methods on that class.</li> <li>Initializing startup classes - Initializing any classes meant to be active at startup by instantiating the class, and then calling the _initialize_ method on that class if it extends **SmackInitializer**. If it does not extend this interface, then initialization will have to take place in a static block of code which is automatically executed when the class is loaded.</li> </ul> <p> Initialization is accomplished via a configuration file. By default, Smack will load the one embedded in the Smack jar at _org.jivesoftware.smack/smack- config.xml_. This particular configuration contains a list of initializer classes to load. All manager type classes that need to be initialized are contained in this list of initializers. </p> </body>