Java 2 Micro Edition (J2ME) is a runtime environment for resource-constrained environments. There are already millions of J2ME enabled mobile devices that support the first version of the Mobile Information Device Profile (MIDP) in J2ME. Many security threats exist in MIDP 1.0 environment since the specification addresses only a limited number of security issues. It is supposed that the next version of the MIDP will have more secure environment for mobile business and personal applications and solve the important security problems in MIDP 1.0.

In this paper, we give short introduction to the J2ME and MIDP environment. Based on existing literature, we explain the threats and security needs in mobile environment for MIDP 1.0 applications. We cover the new security mechanisms and features in MIDP 2.0 and analyze against presented threats, how these address the existing security problems in MIDP 1.0.

In this paper we conclude that MIDP 2.0 improves several different issues in MIDP security. Especially the secure network protocols and signed applications are major improvements. We also conclude that there still exist problems in MIDP 2.0 security, mainly related to the PKI that is part of trusted applications and new secure protocols.