Chapter 1 focuses on Multi threading in Java. Application¿s efficiency can be increased drastically by carefully following the multi threading application design guidelines. In order to cater the needs in this direction our first chapter focuses on all ins and outs of multi threading concepts supported by relevant examples in each case. Chapter 2 covers FAQs on ¿Networking in Javä which focuses primarily on two architectures, connection-oriented and connection-less. The highlights of the chapter including blending multi threading concepts with networking concepts for creating multi threaded servers, multi functional servers, proxy servers and loading balancing servers. Chapter 3 focuses on introduction to Java Applets which are usually used to add small, interactive components or enhancements to a webpage. The salient features of the chapter are passing parameters to the applet, applet restrictions and applet security. Chapter 4 is completely devoted to Java collection Framework, which play a key role in developing applications incorporating business components in middle tier of N-Tier scalable applications in Java.