The electronic lexical databases WordNets, have become essential for many computer applications, especially in linguistic research. Free French WordNet is an XML lexical database for French language based on Princeton WordNet for the English language and other multilingual resources. So far, research on Free French WordNet has focused on the construction and relevance of lexico-semantic information. However, no effort is made to facilitate the exploitation of this database under the Java language. In this context, this paper proposes our approach for the development of a new Java API based on Java Architecture for XML Binding. This Java API will make it easier for developers to exploit and use Free French WordNet to create applications for natural language processing. In order to assess the usefulness of our API, The API performance has been evaluated in the context of a Browser that we developed to extract semantic and lexical relations connecting synsets contained in this database, such as: the tree of hypernymy, the tree of hyponymy, synonyms, etc. The results showed that our API perfectly meets the needs of programmatically exploitation, exploration and consultation of this database in a Java application.