Java Questions

A thread can be created by subclassing Thread, or by implementing the Runnable interface.

These are accessibility modifiers. Private is the most restrictive, while public is the least restrictive. There is no real difference between protected and the default type (also known as package protected) within the context of the same package, however the protected keyword allows visibility to a derived class in a different package.

When an exception is thrown , the catch block of the try statement are examined in the order in which they appear. The first catch block that is capable of handling the exception is executed. The remaining catch blocks are ignored

When creating a thread by extending the Thread class, it is not mandatory to override the run method (If we are not overriding the run method , it is useless), because Thread class have already given a default implementation for run method. But if we are implementing Runnable , it is mandatory to override the run method. The preferred way to create a thread is by implementing Runnable interface, because it give loose coupling.

Overriding means changing behavior of methods of base class in derive class by overriding the base class methods. If class A is a base class with method ’calculate’ and class B inherits class A, thus derives method ’calculate’ of class A. The behavior of ’calculate’ in class B can be changed by overriding it.

Package is a collection of related classes and interfaces. package declaration should be first statement in a java class.

Java uses sand box security model.

By using method.

The method used to set the data is called setter method.