In this paper, the security of Electronic Commerce and the security methods are introduced firstly. Then, the history of Java Security Architecture and its design principles are described. After that, partial implementation of Elliptic Curve Cryptosystem developed with Java is discussed. In the end, the advantages of Electronic Commerce Systems developed with Java language and Java Security Architecture are displayed. Then, the history of Java Security Architecture and its design principles are described. After that, partial implementation of Elliptic Curve Cryptosystem developed with Java is discussed. In the end , the advantages of Electronic Commerce Systems developed with Java language and Java Security Architecture are displayed.