GeoServer is a Java-based software server that lets you view and edit geospatial data. GeoServer allows for great flexibility in map creation and data sharing by making use of open standards set forth by the Open Geospatial Consortium (OGC).
Implementing the Web Map Service (WMS) standard, GeoServer is able to create maps in a variety of output formats. A free mapping library, OpenLayers, is integrated into GeoServer, making map generation both quick and easy.
The GeoServer app is built on Geotools, an open source Java GIS toolkit. GeoServer can display data on any of the popular mapping apps such as Google Maps, Google Earth, Yahoo Maps, and Microsoft Virtual Earth. Additionally, GeoServer can connect with traditional GIS architectures such as ESRI ArcGIS.
As GeoServer is written in Java, it allows you to share and edit geospatial data. It has been designed for interoperability and it publishes data from any major spatial data source using open standards: WMS, WFS, WCS, WPS and REST.