Open Source Network Clients in Java

Pure Java CIFS/SMB client. SMB1/SMB2/SMB3; NTLMSSP, Kerberos; DFS. Actively maintained fork (org.

Pure Java SSH2 implementation. Connect to sshd; port forwarding, X11, SFTP/SCP; password, publickey, keyboard-interactive auth. Used by Ant, Eclipse, NetBeans, Commons VFS.

TCP/UDP client/server library using NIO and Kryo serialization. Object graphs over the wire; RMI; LAN discovery. Desktop and Android; ideal for games.

All-Java web browser and RIA platform. HTML5, JavaScript, CSS3; Cobra rendering engine; browser API and plugins; JavaFX/Swing rendering. MIT for embeddable API.

Smack is a modular Java XMPP client library for instant messaging, presence, and related protocol extensions. It provides APIs for connection management, stanza processing, authentication, and service discovery in XMPP systems. The library supports Java SE and Android deployments for chat and realtime apps.

XNIO is a low-level Java I/O framework that simplifies non-blocking and blocking channel operations for network applications. It abstracts selector management and transport details while exposing APIs for scalable connection handling, callbacks, and protocol-layer integrations such as SSL channels.

Client-side implementations of FTP/FTPS, TFTP, Telnet, NNTP, IMAP/POP3/SMTP, NTP, Whois, Finger, and others. Low-level protocol access; examples included. Actively maintained.

FTP client library for Java. API: put, get, chdir, dir, pwd; active and passive modes; resume; binary/ASCII; directory list parsing. Free (edtFTPj/Free); LGPL; commercial Pro for FTPS/SFTP.

SNMP4J is a Java SNMP stack for building managers and agents with support for SNMPv1, v2c, and v3. It includes secure transports and authentication/privacy protocols for monitoring and device management use cases. The API is designed for integrating SNMP messaging, traps, and command responders into JVM apps.

Java app for real-time network monitoring via SNMP and ICMP. Traffic generation (UDP flood, HTTP load); host discovery with Wireshark/NMap; IPv6 and SNMPv3.

Cross-platform LDAP browser and editor. Search, read, edit; SSL/TLS, SASL; schema support; LDIF import/export. Apache 2-style license; source on SourceForge and GitHub.

SSH-2 protocol library in pure Java. Sessions (remote exec, shell), port forwarding, X11, SCP, SFTP. No JCE dependency; crypto included.

Cross-platform IRC client. Scriptable (Sleep language); console-style with GUI; DCC/CTCP, SSL; 70+ built-in commands.

Graphical Java file transfer client. FTP (own API), SMB, SFTP, NFS, HTTP; recursive up/down, resume, queue; tabbed UI; Web Start. GPL; API dual-licensed.

Java MIB browser: GET/SET for SNMP devices; dynamic MIB loading; tree view. GPL; useful for learning SNMP.

Graphical network monitor: discover devices, draw connections, periodic availability checks. Color-coded status; alert scripts; plugin framework. Java 8+.

GPL WebDAV client with built-in editor and file browser. DAV library usable standalone. HTTP-based collaborative file editing and management.

SSL-Explorer is a Java web-based SSL VPN server that provides remote access to internal applications and network services through a browser interface. It includes policy-driven access control, tunneling features, and a pluggable architecture for integrating authentication and extension modules.

VPPPN is a peer-to-peer VPN implementation in Java and C for creating private overlay networks without routing all traffic through a permanent central gateway. It provides encrypted tunnels and dynamic node connectivity for small distributed environments that need direct secure host-to-host links.

xLightweb is a Java networking library for building HTTP clients and servers with non-blocking I/O primitives. It focuses on high-throughput request handling and provides APIs for protocol handling, connection management, and event-driven network application development on the JVM.

Java network services manager: proxy, TCP (HTTP/HTTPS/FTP), UDP, SOCKS5; connection monitoring; traffic speed limits; site mirroring; antivirus on the fly; modular/XML config.

HTTP client library (end-of-life). Replaced by Apache HttpComponents HttpClient/HttpCore. Legacy docs and downloads still at Jakarta.

Open-source SNMP v1/v2 client and agent in Java. Get/set OID values; SNMP structures as Java objects. From Drexel GICL (site may be offline).

Framework for Java P2P applications. Event model over the network; message-based; define protocol and business logic for rapid P2P development. Hosted on Google Code (archived).

Universal instant messenger: ICQ, MSN, AIM, Yahoo, ComVC in one client. Multiple look-and-feel; fast. Site updated 2012.

Benchmark suite for database engines and ORM. Extensible circuits; framework to add tests and output results as series and graphs. GPL.