How does an applet get loaded into the browser?
The browser then reads the byte code from the class files and performs a verification pass, checking for access violations and invalid opcodes (among other things). The Java Virtual Machine (JVM) then builds an object for each class (provided the objects have not been created by a previous instance), and executes any static code in each objects initialization section. Object initialization also includes the construction of the superclass objects (the superclass files from Applet to Object are typically loaded from the browsers own Java API on the local file system).
If the applet makes it this far without generating security exceptions, missing class errors, or common errors in static code segments, the JVM will make calls to initialization functions in the superclass, then to the applets init() member.