Java Questions

By using method.

The method used to get the data is called getter method.

Java uses sand box security model.

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

String class objects are immutable objects and they represents strings( sequence of characters)

StringBuffer class objects are mutable objects representing strings and they are Thread safe

StringBuild class objects are also mutable objects representing strings and they are not Thread safe

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.

- The Dictionary class is an abstract class.

- Classes like Hashtable which map keys to values inherit from this class. 

- An object can be looked for if a dictionary and a key is provided.

- Any non-null object can be used as a key and as a value.

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

Array is collection of same data type. Array size is fixed, It cannot be expanded.

But ArrayList is a growable collection of objects.ArrayList is a part of Collections Framework and can work with only objects.