Hello and welcome to the forums.
A Java package is a mechanism for organizing Java classes into namespaces similar to the modules of Modula. Java packages can be stored in compressed files called JAR files, allowing classes to download faster as a group rather than one at a time. Programmers also typically use packages to organize classes belonging to the same category or providing similar functionality.
Eclipse gives you the option to name the package whatever you like. When you create a package, your bin and src folders for that project will be in there. If you do not set a package, it defaults to the default package.