When a class is loaded and initialized in JVM
http://javarevisited.blogspot.com/2012/07/when-class-loading-initialization-java-example.html
When Class is loaded in Java
Class loading is done by ClassLoaders in Java which can be implemented to eagerly load a class as soon as another class references it or lazy load the class until a need of class initialization occurs.
While its guaranteed by JLS that a class will be loaded when there is a need of static initialization.
When a Class is initialized in Java
After class loading, initialization of class takes place which means initializing all static members of class. A Class is initialized in Java when :
1) an Instance of class is created using either new() keyword or using reflection using class.forName(), which may throw ClassNotFoundException in Java.
2) an static method of Class is invoked.
3) an static field of Class is assigned.
4) an static field of class is used which is not a constant variable.
5) if Class is a top level class and an assert statement lexically nested within class is executed.
How Class is initialized in Java
1) Classes are initialized from top to bottom so field declared on top initialized before field declared in bottom
2) Super Class is initialized before Sub Class or derived class in Java
3) If Class initialization is triggered due to access of static field, only Class which has declared static field is initialized and it doesn't trigger initialization of super class or sub class even if static field is referenced by Type of Sub Class, Sub Interface or by implementation class of interface.
4) interface initialization in Java doesn't cause super interfaces to be initialized.
5) static fields are initialized during static initialization of class while non static fields are initialized when instance of class is created. It means static fields are initialized before non static fields in Java.
6)non static fields are initialized by constructors in Java. sub class constructor implicitly call super class constructor before doing any initialization, which guarantees that non static or instance variables of super class is initialized before sub class.
http://javarevisited.blogspot.com/2012/07/when-class-loading-initialization-java-example.html
When Class is loaded in Java
Class loading is done by ClassLoaders in Java which can be implemented to eagerly load a class as soon as another class references it or lazy load the class until a need of class initialization occurs.
While its guaranteed by JLS that a class will be loaded when there is a need of static initialization.
When a Class is initialized in Java
After class loading, initialization of class takes place which means initializing all static members of class. A Class is initialized in Java when :
1) an Instance of class is created using either new() keyword or using reflection using class.forName(), which may throw ClassNotFoundException in Java.
2) an static method of Class is invoked.
3) an static field of Class is assigned.
4) an static field of class is used which is not a constant variable.
5) if Class is a top level class and an assert statement lexically nested within class is executed.
How Class is initialized in Java
1) Classes are initialized from top to bottom so field declared on top initialized before field declared in bottom
2) Super Class is initialized before Sub Class or derived class in Java
3) If Class initialization is triggered due to access of static field, only Class which has declared static field is initialized and it doesn't trigger initialization of super class or sub class even if static field is referenced by Type of Sub Class, Sub Interface or by implementation class of interface.
4) interface initialization in Java doesn't cause super interfaces to be initialized.
5) static fields are initialized during static initialization of class while non static fields are initialized when instance of class is created. It means static fields are initialized before non static fields in Java.
6)non static fields are initialized by constructors in Java. sub class constructor implicitly call super class constructor before doing any initialization, which guarantees that non static or instance variables of super class is initialized before sub class.
