| Java architecture includes four interrelated technologies, including Java language, Java API, class file and Java virtual machine. Java virtual machine is the core of the java architecture and it makes Java programs transplanted between different computer systems with high portability.In this thesis class loader, execute engine and garbage collection mechanisms are studied. The aspects are as follows. Class loader analysis includes class file format, constant pool resolution, dynamic loading and the model of parents assignment. The traditional method of class name storage includes all class name path, which contains a lot of redundant information. The proposed method improves the table of Utf8_info, puts the fully qualified name of class in Utf8_info table with different nodes. This reduces the space of constant pool, thereby reducing the class file size, especially saves space in limited memory system.Regarding the execute engine, the work area of stack, instruction set, and the functions of the execute technology are discussed. Finally some instructions are designed and implemented according to standard Java virtual machine specification.In storage management, java virtual machine are compared to traditional system. Garbage collection algorithms are introduced and resolution of the failure of the train algorithm are proposed. Finally a scheme of generational collection in KVM is designed, which simply divided the memory heap into young generation and old generation. The experiment result shows a little upgrade of performance compared to the default garbage collection method in KVM. |
