JVM class loader loading process

Transfer: http://yizhenn.iteye.com/blog/2299034

There are three default class loaders, Bootstrap ClassLoader, Extension CLassLoader and App ClassLoader. Among them, Bootstrap Classloader is used to load the core class library of JAVA, Extension Classloader is used to load the extension class library of JAVA, and App ClassLoader is used to load user-defined classes in the classpath.