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Serialization is the process of writing the state of an object to a byte stream. Deserialization is the process of restoring these objects.

A static variable is associated with the class as a whole rather than with specific instances of a class. Non-static variables take on unique values with each object instance.

The Class class is used to obtain information about an object's design and java.lang.Class class instance represent classes, interfaces in a running Java application.

The Reader/Writer class hierarchy is character-oriented, and the InputStream/OutputStream class hierarchy is byte-oriented.

It is used to create objects that provide access to the files and directories of a local file system.

The paint() method supports painting via a Graphics object. The repaint() method is used to cause paint() to be invoked by the AWT painting thread.

javax.Swing package. All components in Swing, except JApplet, JDialog, JFrame and JWindow are lightweight components.

The Frame class extends Window to define a main application window that can have a menu bar.

These are classes that allow primitive types to be accessed as objects. Example: Integer, Character, Double, Boolean etc.

Unicode requires 16 bits and ASCII require 7 bits. Although the ASCII character set uses only 7 bits, it is usually represented as 8 bits. UTF-8 represents characters using 8, 16, and 18 bit patterns. UTF-16 uses 16-bit and larger bit patterns.

The Vector class provides the capability to implement a growable array of objects. Vector proves to be very useful if you don't know the size of the array in advance, or you just need one that can change sizes over the lifetime of a program.

Yes, it does. The FileNoFoundException is inherited from the IOException. Exception's subclasses have to be caught first.

After a thread is started, via its start() method of the Thread class, the JVM invokes the thread's run() method when the thread is initially executed.

The operating system's task scheduler allocates execution time to multiple tasks. By quickly switching between executing tasks, it creates the impression that tasks execute sequentially.

A thread can enter the waiting state by invoking its sleep() method, by blocking on IO, by unsuccessfully attempting to acquire an object's lock, or by invoking an object's wait() method. It can also enter the waiting state by invoking its (deprecated) suspend() method.

A NullPointerException is thrown when calling the instance method of a null object, accessing or modifying the field of a null object etc.

Final classes are created so the methods implemented by that class cannot be overridden. It can’t be inherited.

Method overloading increases the readability of the program. Method overriding provides the specific implementation of the method that is already provided by its super class parameter must be different in case of overloading, parameter must be same in case of overriding.

Holding the reference of the other class within some other class is known as composition.

It is used to initialize the static data member, It is excuted before main method at the time of classloading.

No, this is not possible.

The java compiler creates a default constructor only if there is no constructor in the class.

Object based programming languages follow all the features of OOPs except Inheritance. JavaScript is an example of object based programming languages.

It improves the runtime performance of computer programs based on bytecode.

This is Web Archive File and used to store XML, java classes, and JavaServer pages. which is used to distribute a collection of JavaServer Pages, Java Servlets, Java classes, XML files, static Web pages etc.

JAR files is Java Archive fles and it aggregates many files into one. It holds Java classes in a library. JAR files are built on ZIP file format and have .jar file extension.

Java Runtime Environment is an implementation of the Java Virtual Machine which executes Java programs. It provides the minimum requirements for executing a Java application;

The following shows the explanation individually −

• public − it is the access specifier.

• static − it allows main() to be called without instantiating a particular instance of a class.

• void − it affirns the compiler that no value is returned by main().

• main() − this method is called at the beginning of a Java program.

• String args[ ] − args parameter is an instance array of class String

It includes:

• Throw is used to trigger an exception where as throws is used in declaration of exception.

• Without throws, Checked exception cannot be handled where as checked exception can be propagated with throws.

It is used to sort collections and arrays of objects using the collections.sort() and java.utils. The objects of the class implementing the Comparable interface can be ordered.

It is a Set implemented when we want elements in a sorted order.

It is a collection of element which cannot contain duplicate elements. The Set interface contains only methods inherited from Collection and adds the restriction that duplicate elements are prohibited.

It is used with variables or methods and used to call constructer of same class.

An immutable object can’t be changed once it is created.

It uses garbage collection to free the memory. By cleaning those objects that is no longer reference by any of the program.

An applet extends java.applet.Applet class.

An applet is a Java program that runs in a Web browser. An applet can be a fully functional Java application because it has the entire Java API at its disposal.

Thread can be created by: implementing Runnable interface, extending the Thread class.

A multithreaded program contains two or more parts that can run concurrently. Each part of such a program is called a thread, and each thread defines a separate path of execution.

Packages are used in Java in-order to prevent naming conflicts, to control access, to make searching/locating and usage of classes, interfaces, enumerations and annotations, etc., easier.

A Package can be defined as a grouping of related types(classes, interfaces, enumerations and annotations ) providing access protection and name space management.

It includes −

• Interface cannot be instantiated

• An interface does not contain any constructors.

• All of the methods in an interface are abstract.

The main benefit of encapsulation is the ability to modify our implemented code without breaking the code of others who use our code. With this Encapsulation gives maintainability, flexibility and extensibility to our code.

If you want a class to contain a particular method but you want the actual implementation of that method to be determined by child classes, you can declare the method in the parent class as abstract.

These classes cannot be instantiated and are either partially implemented or not at all implemented. This class contains one or more abstract methods which are simply method declarations without a body.

If the method overrides one of its superclass's methods, overridden method can be invoked through the use of the keyword super. It can be also used to refer to a hidden field.

It is the process where one object acquires the properties of another. With the use of inheritance the information is made manageable in a hierarchical order.

While creating your own exception −

• All exceptions must be a child of Throwable.

• If you want to write a checked exception that is automatically enforced by the Handle or Declare Rule, you need to extend the Exception class.

• You want to write a runtime exception, you need to extend the RuntimeException class.

The finally keyword is used to create a block of code that follows a try block. A finally block of code always executes, whether or not an exception has occurred.

An exception can be thrown, either a newly instantiated one or an exception that you just caught, by using throw keyword.