读书笔记-Java体系结构

 

Figure 1-1. The Java programming environment.

Figure 1-2. Java programs run on top of the Java Platform.

Figure 1-3. A basic block diagram of the Java virtual machine.

Figure 1-4. A Java virtual machine implemented in software on top of a host operating system.

 

 

Figure 1-5. Java's class loader architecture.

Because of user-defined class loaders, you don't have to know at compile-time all the classes that may ultimately take part in a running Java application. User-defined class loaders enable you to dynamically extend a Java application at run-time. As it runs, your application can determine what extra classes it needs and load them through one or more user-defined class loaders. Because you write the class loader in Java, you can load classes in any manner expressible in Java code. You can download them across a network, get them out of some kind of database, or even calculate them on the fly.

 

 

Figure 1-6. A platform-independent Java program.