STRONG MOBILITY FOR JAVA BASED MOBILE AGENT SYSTEMS

Abstract

Mobile agents are an emerging technology that promises easy design and implementation of distributed systems. With the advent of Java, the mobile agent camp saw a new streak of light as the problem of portability and heterogeneous architectures was solved. Java Security promised running of agents would be safe, as only the JVM would grant resources to the agents. Java provided the abstraction of a virtual machine over varied platforms. But there lie various difficulties in the path of Java based Mobile Agent paradigm. The Java Security, which was one of the attractions, became a tight neck for the mobility of agents. Java does not allow threads to be migrated. By migration we mean the movement of an agent to another location and transparent continuation ahead from the point before the migration occurred. This means, code, data and execution information (basically, the thread) of the agent must be transferred to and restored at the other location. But, the standard Java API does not provide access to the execution state of Java threads; this state remains inaccessible to Java programmers. In order to address the issue of the portability of the migration mechanism on multiple Java environments, a solution has been proposed at the application level, for maximum portability. This approach is based on a pre-processor that is applied to the code of the application prior to execution; this preprocessor transforms the code in order to add statements, which capture and restore the state of the thread. This pre-processor is written in Java language on a Pentium IV processor 1600 MHz and runs on all platforms.