Name Container classes. ?

Window, Frame, Dialog, FileDialog, Panel, Applet, or ScrollPane

What class allows you to read objects directly from a stream?

The ObjectInputStream class supports the reading of objects from input streams.

How are this() and super() used with constructors?

this() is used to invoke a constructor of the same class. super() is used to invoke a superclass constructor.

How is it possible for two String objects with identical values not to be equal under the == operator?

The == operator compares two objects to determine if they are the same object in memory. It is possible for two String objects to have the same value, but located indifferent areas of memory.

What an I/O filter?

An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.

What is the Set interface?

The Set interface provides methods for accessing the elements of a finite mathematical set. Sets do not allow duplicate elements.

What is the List interface?

The List interface provides support for ordered collections of objects.

What is the purpose of the enableEvents() method?

The enableEvents() method is used to enable an event for a particular object. Normally, an event is enabled when a listener is added to an object for a particular event. The enableEvents() method is used by objects that handle events by overriding their event-dispatch methods.

What is the difference between the File and RandomAccessFile classes?

The File class encapsulates the files and directories of the local file system. The RandomAccessFile class provides the methods needed to directly access data contained in any part of a file.

What interface must an object implement before it can be written to a stream as an object?

An object must implement the Serializable or Externalizable interface before it can be written to a stream as an object.

What is the ResourceBundle class?

The ResourceBundle class is used to store locale-specific resources that can be loaded by a program to tailor the program's appearance to the particular locale in which it is being run.

What is the difference between a Scrollbar and a ScrollPane?

A Scrollbar is a Component, but not a Container. A ScrollPane is a Container. A ScrollPane handles its own events and performs its own scrolling.

What is a Java package and how is it used?

A Java package is a naming context for classes and interfaces. A package is used to create a separate name space for groups of classes and interfaces. Packages are also used to organize related classes and interfaces into a single API unit and to control accessibility to these classes and interfaces.

What are the Object and Class classes used for?

The Object class is the highest-level class in the Java class hierarchy. The Class class is used to represent the classes and interfaces that are loaded by a Java program.

What is Serialization and deserialization?

Serialization is the process of writing the state of an object to a byte stream.

Deserialization is the process of restoring these objects.

What is tunnelling?

Tunnelling is a route to somewhere. For example, RMI tunnelling is a way to make RMI application get through firewall. In CS world, tunnelling means a way to transfer data.

Does the code in finally block get executed if there is an exception and a return statement in a catch block?

If an exception occurs and there is a return statement in catch block, the finally block is still executed. The finally block will not be executed when the System.exit(1) statement is executed earlier or the system shut down earlier or the memory is used up earlier before the thread goes to finally block.

How you restrict a user to cut and paste from the html page?

Using javaScript to lock keyboard keys. It is one of solutions.

Is Java a super set of JavaScript?

No. They are completely different. Some syntax may be similar.

What is a Container in a GUI?

A Container contains and arranges other components (including other containers) through the use of layout managers, which use specific layout policies to determine where components should go as a function of the size of the container.

How the object oriented approach helps us keep complexity of software development under control?

We can discuss such issue from the following aspects:

Objects allow procedures to be encapsulated with their data to reduce potential interference.

Inheritance allows well-tested procedures to be reused and enables changes to make once and have effect in all relevant places.

The well-defined separations of interface and implementation allows constraints to be imposed on inheriting classes while still allowing the flexibility of overriding and overloading.

What is polymorphism?

Polymorphism allows methods to be written that needn't be concerned about the specifics of the objects they will be applied to. That is, the method can be specified at a higher level of abstraction and can be counted on to work even on objects of yet unconceived classes.

What is design by contract?

The design by contract specifies the obligations of a method to any other methods that may use its services and also theirs to it. For example, the preconditions specify what the method required to be true when the method is called. Hence making sure that preconditions are. Similarly, post conditions specify what must be true when the method is finished, thus the called method has the responsibility of satisfying the post conditions.

In Java, the exception handling facilities support the use of design by contract, especially in the case of checked exceptions. The assert keyword can be used to make such contracts.

What are use cases?

A use case describes a situation that a program might encounter and what behavior the program should exhibit in that circumstance. It is part of the analysis of a program. The collection of use cases should, ideally, anticipate all the standard circumstances and many of the extraordinary circumstances possible so that the program will be robust.