Thursday, 1 September 2016

Java - Class loaders ~ gniithelp

ClassLoaders
Ø Class loaders are hierarchical.
Ø Classes are introduced into the JVM as they are referenced by name in a class that is already running in the JVM.
Ø Class loader creates a namespace.
All JVMs include at least one class loader that is embedded within the JVM called the primordial (or bootstrap) class loader.
Ø API
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A class loader is an object that is responsible for loading classes.
class ClassLoader is an abstract class.
Given the binary name of a class, a class loader should attempt to locate or generate data that constitutes a definition for the class. A typical strategy is to transform the name into a file name and then read a "class file" of that name from a file system.



how is the very first class loaded?
The very first class is especially loaded with the help of static main( ) method declared in your class. All the subsequently loaded classes are loaded by the classes, which are already loaded and running.
Class loaders are hierarchical and use a delegation model when loading a class. Class loaders request their parent to load the class first before attempting to load it themselves. When a class loader loads a class, the child class loaders in the hierarchy will never reload the class again
Classes loaded by a child class loader have visibility into classes loaded by its parents
Explain static vs. dynamic class loading?


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