To schedule/manage any thread we must have object of Thread class. As such main thread is not created by developer we have to get the object from Runtime by calling a simple method.

class mainThread
{
	public static void main(String[] s)
	{
		Thread t = Thread.currentThread();
	}
}

Now object “t” can be used to call any method of Thread class. Which will ultimately control the main Thread. e.g.

class mainThread
{
	public static void main(String[] s) throws InterruptedException
	{
		Thread t = Thread.currentThread();
		System.out.println("Thread Started");
		t.sleep(1000);
		System.out.println("After Sleep");
	}
}

On calling t.sleep(1000) method the execution will be paused for 1second and then it will execute further. Method sleep(int) throws an InterruptedException which can be handled by applying “throws InterruptedException” clause.

If we really want to track the execution, We can print the Date object as below:

The post What is Thread? appeared first on Ankit Virparia.

1	The History and Evolution of Java
	Java’s Lineage
	The Birth of Modern Programming: C
	C++: The Next Step
	The Stage Is Set for Java
	The Creation of Java
	The C# Connection
	How Java Changed the Internet
	Java Applets
	Security
	Portability
	Java’s Magic: The Bytecode
	Servlets: Java on the Server Side
	The Java Buzzwords
	Simple
	Object-Oriented
	Robust
	Multithreaded
	Architecture-Neutral
	Interpreted and High Performance
	Distributed
	Dynamic
	The Evolution of Java
	Java SE 6
	A Culture of Innovation
2	An Overview of Java
	Object-Oriented Programming
	Two Paradigms
	Abstraction
	The Three OOP Principles
	A First Simple Program
	Entering the Program
	Compiling the Program
	A Closer Look at the First Sample Program
	A Second Short Program
	Two Control Statements
	The if Statement
	The for Loop
	Using Blocks of Code
	Lexical Issues
	Whitespace
	Identifiers
	Literals
	Comments
	Separators
	The Java Keywords
	The Java Class Libraries
3	Data Types, Variables, and Arrays
	Java Is a Strongly Typed Language
	The Primitive Types
	Integers
	byte
	short
	int
	long
	Floating-Point Types
	float
	double
	Characters
	Booleans
	A Closer Look at Literals
	Integer Literals
	Floating-Point Literals
	Boolean Literals
	Character Literals
	String Literals
	Variables
	Declaring a Variable
	Dynamic Initialization
	The Scope and Lifetime of Variables
	Type Conversion and Casting
	Java’s Automatic Conversions
	Casting Incompatible Types
	Automatic Type Promotion in Expressions
	The Type Promotion Rules
	Arrays
	One-Dimensional Arrays
	Multidimensional Arrays
	Alternative Array Declaration Syntax
	A Few Words About Strings
	A Note to C/C++ Programmers About Pointers
4	Operators
	Arithmetic Operators
	The Basic Arithmetic Operators
	The Modulus Operator
	Arithmetic Compound Assignment Operators
	Increment and Decrement
	The Bitwise Operators
	The Bitwise Logical Operators
	The Left Shift
	The Right Shift
	The Unsigned Right Shift
	Bitwise Operator Compound Assignments
	Relational Operators
	Boolean Logical Operators
	Short-Circuit Logical Operators
	The Assignment Operator
	The ? Operator
	Operator Precedence
	Using Parentheses
5	Control Statements
	Java’s Selection Statements
	if
	switch
	Iteration Statements
	while
	do-while
	for
	The For-Each Version of the for Loop
	Nested Loops
	Jump Statements
	Using break
	Using continue
	return
6	Introducing Classes
	Class Fundamentals
	The General Form of a Class
	A Simple Class
	Declaring Objects
	A Closer Look at new
	Assigning Object Reference Variables
	Introducing Methods
	Adding a Method to the Box Class
	Returning a Value
	Adding a Method That Takes Parameters
	Constructors
	Parameterized Constructors
	The this Keyword
	Instance Variable Hiding
	Garbage Collection
	The finalize( ) Method
	A Stack Class
7	A Closer Look at Methods and Classes
	Overloading Methods
	Overloading Constructors
	Using Objects as Parameters
	A Closer Look at Argument Passing
	Returning Objects
	Recursion
	Introducing Access Control
	Understanding static
	Introducing final
	Arrays Revisited
	Introducing Nested and Inner Classes
	Exploring the String Class
	Using Command-Line Arguments
	Varargs: Variable-Length Arguments
	Overloading Vararg Methods
	Varargs and Ambiguity
8	Inheritance
	Inheritance Basics
	Member Access and Inheritance
	A More Practical Example
	A Superclass Variable Can Reference a Subclass Object
	Using super
	Using super to Call Superclass Constructors
	A Second Use for super
	Creating a Multilevel Hierarchy
	When Constructors Are Called
	Method Overriding
	Dynamic Method Dispatch
	Why Overridden Methods?
	Applying Method Overriding
	Using Abstract Classes
	Using final with Inheritance
	Using final to Prevent Overriding
	Using final to Prevent Inheritance
	The Object Class
9	Packages and Interfaces
	Packages
	Defining a Package
	Finding Packages and CLASSPATH
	A Short Package Example
	Access Protection
	An Access Example
	Importing Packages
	Interfaces
	Defining an Interface
	Implementing Interfaces
	Nested Interfaces
	Applying Interfaces
	Variables in Interfaces
	Interfaces Can Be Extended
10	Exception Handling
	Exception-Handling Fundamentals
	Exception Types
	Uncaught Exceptions
	Using try and catch
	Displaying a Description of an Exception
	Multiple catch Clauses
	Nested try Statements
	throw
	throws
	finally
	Java’s Built-in Exceptions
	Creating Your Own Exception Subclasses
	Chained Exceptions
	Using Exceptions
11	Multithreaded Programming
	The Java Thread Model
	Thread Priorities
	Synchronization
	Messaging
	The Thread Class and the Runnable Interface
	The Main Thread
	Creating a Thread
	Implementing Runnable
	Extending Thread
	Choosing an Approach
	Creating Multiple Threads
	Using isAlive( ) and join( )
	Thread Priorities
	Synchronization
	Using Synchronized Methods
	The synchronized Statement
	Interthread Communication
	Deadlock
	Suspending, Resuming, and Stopping Threads
	The Modern Way of Suspending, Resuming and Stopping Threads
	Using Multithreading
12	Enumerations, Autoboxing, and Annotations (Metadata)
	Enumerations
	Enumeration Fundamentals
	The values( ) and valueOf( ) Methods
	Java Enumerations Are Class Types
	Enumerations Inherit Enum
	Another Enumeration Example
	Type Wrappers
	Autoboxing
	Autoboxing and Methods
	Autoboxing/Unboxing Occurs in Expressions
	Autoboxing/Unboxing Boolean and Character Values
	Autoboxing/Unboxing Helps Prevent Errors
	AWord of Warning
	Annotations (Metadata)
	Annotation Basics
	Specifying a Retention Policy
	Obtaining Annotations at Run Time by Use of Reflection
	The AnnotatedElement Interface
	Using Default Values
	Marker Annotations
	Single-Member Annotations
	The Built-In Annotations
	Some Restrictions
13	I/O, Applets, and Other Topics
	I/O Basics
	Streams
	Byte Streams and Character Streams
	The Predefined Streams
	Reading Console Input
	Reading Characters
	Reading Strings
	Writing Console Output
	The PrintWriter Class
	Reading and Writing Files
	Applet Fundamentals
	The transient and volatile Modifiers
	Using instanceof
	strictfp
	Native Methods
	Problems with Native Methods
	Using assert
	Assertion Enabling and Disabling Options
	Static Import
	Invoking Overloaded Constructors Through this( )
14	Generics
	What Are Generics?
	A Simple Generics Example
	Generics Work Only with Objects
	Generic Types Differ Based on Their Type Arguments
	How Generics Improve Type Safety
	A Generic Class with Two Type Parameters
	The General Form of a Generic Class
	Bounded Types
	Using Wildcard Arguments
	Bounded Wildcards
	Creating a Generic Method
	Generic Constructors
	Generic Interfaces
	Raw Types and Legacy Code
	Generic Class Hierarchies
	Using a Generic Superclass
	A Generic Subclass
	Run-Time Type ComparisonsWithin a Generic Hierarchy
	Casting
	Overriding Methods in a Generic Class
	Erasure
	Bridge Methods
	Ambiguity Errors
	Some Generic Restrictions
	Type Parameters Can Be Instantiated
	Restrictions on Static Members
	Generic Array Restrictions
	Generic Exception Restriction
	Final Thoughts on Generics
15	String Handling
	The String Constructors
	String Length
	Special String Operations
	String Literals
	String Concatenation
	String Concatenation with Other Data Types
	String Conversion and toString( )
	Character Extraction
	charAt( )
	getChars( )
	getBytes( )
	toCharArray( )
	String Comparison
	equals( ) and equalsIgnoreCase( )
	regionMatches( )
	startsWith( ) and endsWith( )
	equals( ) Versus ==
	compareTo( )
	Searching Strings
	Modifying a String
	substring( )
	concat( )
	replace( )
	trim( )
	Data Conversion Using valueOf( )
	Changing the Case of Characters Within a String
	Additional String Methods
	StringBuffer
	StringBuffer Constructors
	length( ) and capacity( )
	ensureCapacity( )
	setLength( )
	charAt( ) and setCharAt( )
	getChars( )
	append( )
	insert( )
	reverse( )
	delete( ) and deleteCharAt( )
	replace( )
	substring( )
	Additional StringBuffer Methods
	StringBuilder
16	Exploring java
	Primitive Type Wrappers
	Number
	Double and Float
	Byte, Short, Integer, and Long
	Character
	Recent Additions to Character for Unicode Code
	Point Support
	Boolean
	Void
	Process
	Runtime
	Memory Management
	Executing Other Programs
	ProcessBuilder
	System
	Using currentTimeMillis( ) to Time Program Execution
	Using arraycopy( )
	Environment Properties
	Object
	Using clone( ) and the Cloneable Interface
	Class
	ClassLoader
	Math
	Transcendental Functions
	Exponential Functions
	Rounding Functions
	Miscellaneous Math Methods
	StrictMath
	Compiler
	Thread, ThreadGroup, and Runnable
	The Runnable Interface
	Thread
	ThreadGroup
	ThreadLocal and InheritableThreadLocal
	Package
	RuntimePermission
	Throwable
	SecurityManager
	StackTraceElement
	Enum
	The CharSequence Interface
	The Comparable Interface
	The Appendable Interface
	The Iterable Interface
	The Readable Interface
17	java Collection Framework
	Recent Changes to Collections
	Generics Fundamentally Change the Collections
	Framework
	Autoboxing Facilitates the Use of Primitive Types
	The For-Each Style for Loop
	The Collection Interfaces
	The Collection Interface
	The List Interface
	The Set Interface
	The SortedSet Interface
	The NavigableSet Interface
	The Queue Interface
	The Deque Interface
	The Collection Classes
	The ArrayList Class
	The LinkedList Class
	The HashSet Class
	The LinkedHashSet Class
	The TreeSet Class
	The PriorityQueue Class
	The ArrayDeque Class
	The EnumSet Class
	Accessing a Collection via an Iterator
	Using an Iterator
	The For-Each Alternative to Iterators
	Storing User-Defined Classes in Collections
	The RandomAccess Interface
	Working with Maps
	The Map Interfaces
	The NavigableMap Interface
	The Map Classes
	Comparators
	Using a Comparator
	The Collection Algorithms
	Arrays
	Why Generic Collections?
	The Legacy Classes and Interfaces
	The Enumeration Interface
	Vector
	Stack
	Dictionary
	Hashtable
	Properties
	Using store( ) and load( )
	Parting Thoughts on Collections
18	java – More Util Classes
	StringTokenizer
	BitSet
	Date
	Calendar
	GregorianCalendar
	TimeZone
	SimpleTimeZone
	Locale
	Random
	Observable
	The Observer Interface
	An Observer Example
	Timer and TimerTask
	Currency
	Formatter
	The Formatter Constructors
	The Formatter Methods
	Formatting Basics
	Formatting Strings and Characters
	Formatting Numbers
	Formatting Time and Date
	The %n and %% Specifiers
	Specifying a Minimum Field Width
	Specifying Precision
	Using the Format Flags
	Justifying Output
	The Space, +, 0, and ( Flags
	The Comma Flag
	The # Flag
	The Uppercase Option
	Using an Argument Index
	The Java printf( ) Connection
	Scanner
	The Scanner Constructors
	Scanning Basics
	Some Scanner Examples
	Setting Delimiters
	Other Scanner Features
	The ResourceBundle, ListResourceBundle,
	andPropertyResourceBundle Classes
	Miscellaneous Utility Classes and Interfaces
19	Input/Output: Exploring java
	The Java I/O Classes and Interfaces
	File
	Directories
	Using FilenameFilter
	The listFiles( ) Alternative
	Creating Directories
	The Closeable and Flushable Interfaces
	The Stream Classes
	The Byte Streams
	InputStream
	OutputStream
	FileInputStream
	FileOutputStream
	ByteArrayInputStream
	ByteArrayOutputStream
	Filtered Byte Streams
	Buffered Byte Streams
	SequenceInputStream
	PrintStream
	DataOutputStream and DataInputStream
	RandomAccessFile
	The Character Streams
	Reader
	Writer
	FileReader
	FileWriter
	CharArrayReader
	CharArrayWriter
	BufferedReader
	BufferedWriter
	PushbackReader
	PrintWriter
	The Console Class
	Using Stream I/O
	Improving wc( ) Using a StreamTokenizer
	Serialization
	Serializable
	Externalizable
	ObjectOutput
	ObjectOutputStream
	ObjectInput
	ObjectInputStream
	A Serialization Example
	Stream Benefits
20	Networking
	Networking Basics
	The Networking Classes and Interfaces
	InetAddress
	Factory Methods
	Instance Methods
	Inet4Address and Inet6Address
	TCP/IP Client Sockets
	URL
	URLConnection
	HttpURLConnection
	The URI Class
	Cookies
	TCP/IP Server Sockets
	Datagrams
	DatagramSocket
	DatagramPacket
	A Datagram Example
21	The Applet Class
	Two Types of Applets
	Applet Basics
	The Applet Class
	Applet Architecture
	An Applet Skeleton
	Applet Initialization and Termination
	Overriding update( )
	Simple Applet Display Methods
	Requesting Repainting
	A Simple Banner Applet
	Using the Status Window
	The HTML APPLET Tag
	Passing Parameters to Applets
	Improving the Banner Applet
	getDocumentBase( ) and getCodeBase( )
	AppletContext and showDocument( )
	The AudioClip Interface
	The AppletStub Interface
	Outputting to the Console
22	Event Handling
	Two Event Handling Mechanisms
	The Delegation Event Model
	Events
	Event Sources
	Event Listeners
	Event Classes
	The ActionEvent Class
	The AdjustmentEvent Class
	The ComponentEvent Class
	The ContainerEvent Class
	The FocusEvent Class
	The InputEvent Class
	The ItemEvent Class
	The KeyEvent Class
	The MouseEvent Class
	The MouseWheelEvent Class
	The TextEvent Class
	The WindowEvent Class
	Sources of Events
	Event Listener Interfaces
	The ActionListener Interface
	The AdjustmentListener Interface
	The ComponentListener Interface
	The ContainerListener Interface
	The FocusListener Interface
	The ItemListener Interface
	The KeyListener Interface
	The MouseListener Interface
	The MouseMotionListener Interface
	The MouseWheelListener Interface
	The TextListener Interface
	The WindowFocusListener Interface
	The WindowListener Interface
	Using the Delegation Event Model
	Handling Mouse Events
	Handling Keyboard Events
	Adapter Classes
	Inner Classes
	Anonymous Inner Classes
23	Introducing the AWT: Working with Windows, Graphics
	AWT Classes
	Window Fundamentals
	Component
	Container
	Panel
	Window
	Frame
	Canvas
	Working with Frame Windows
	Setting the Window’s Dimensions
	Hiding and Showing a Window
	Setting a Window’s Title
	Closing a Frame Window
	Creating a Frame Window in an Applet
	Handling Events in a Frame Window
	Creating a Windowed Program
	Displaying Information Within a Window
	Working with Graphics
	Drawing Lines
	Drawing Rectangles
	Drawing Ellipses and Circles
	Drawing Arcs
	Drawing Polygons
	Sizing Graphics
	Working with Color
	Color Methods
	Setting the Current Graphics Color
	A Color Demonstration Applet
	Setting the Paint Mode
	Working with Fonts
	Determining the Available Fonts
	Creating and Selecting a Font
	Obtaining Font Information
	Managing Text Output Using FontMetrics
	Displaying Multiple Lines of Text
	Centering Text
	Multiline Text Alignment
24	Using AWT Controls, Layout Managers, and Menus
	Control Fundamentals
	Adding and Removing Controls
	Responding to Controls
	The HeadlessException
	Labels
	Using Buttons
	Handling Buttons
	Applying Check Boxes
	Handling Check Boxes
	CheckboxGroup
	Choice Controls
	Handling Choice Lists
	Using Lists
	Handling Lists
	Managing Scroll Bars
	Handling Scroll Bars
	Using a TextField
	Handling a TextField
	Using a TextArea
	Understanding Layout Managers
	FlowLayout
	BorderLayout
	Using Insets
	GridLayout
	CardLayout
	GridBagLayout
	Menu Bars and Menus
	Dialog Boxes
	FileDialog
	Handling Events by Extending AWT Components
	Extending Button
	Extending Checkbox
	Extending a Check Box Group
	Extending Choice
	Extending List
	Extending Scrollbar
25	Images
	File Formats
	Image Fundamentals: Creating, Loading, and Displaying
	Creating an Image Object
	Loading an Image
	Displaying an Image
	ImageObserver
	Double Buffering
	MediaTracker
	ImageProducer
	Memory image source
	ImageConsumer
	PixelGrabber
	ImageFilter
	CropImageFilter
	RGBImageFilter
	Cell Animation
	Additional Imaging Classes
26	The Concurrency Utilities
	The Concurrent API Packages
	Using Synchronization Objects
	Semaphore
	CountDownLatch
	CyclicBarrier
	Exchanger
	Using an Executor
	A Simple Executor Example
	Using Callable and Future
	The TimeUnit Enumeration
	The Concurrent Collections
	Locks
	Atomic Operations
	The Concurrency Utilities Versus Java’s Traditional Approach
27	NIO, Regular Expressions, and Other Packages
	The Core Java API Packages
	NIO
	NIO Fundamentals
	Charsets and Selectors
	Using the NIO System
	Is NIO the Future of I/O Handling?
	Regular Expression Processing
	Pattern
	Matcher
	Regular Expression Syntax
	Demonstrating Pattern Matching
	Two Pattern-Matching Options
	Exploring Regular Expressions
	Reflection
	Remote Method Invocation (RMI)
	A Simple Client/Server Application Using RMI
	Text Formatting
	DateFormat Class
	SimpleDateFormat Class
	Part III Software Development Using Java
28	Java Beans
	What Is a Java Bean?
	Advantages of Java Beans
	Introspection
	Design Patterns for Properties
	Design Patterns for Events
	Methods and Design Patterns
	Using the BeanInfo Interface
	Bound and Constrained Properties
	Persistence
	Customizers
	The Java Beans API
	Introspector
	PropertyDescriptor
	EventSetDescriptor
	MethodDescriptor
	A Bean Example
29	Introducing Swing
	The Origins of Swing
	Swing Is Built on the AWT
	Two Key Swing Features
	Swing Components Are Lightweight
	Swing Supports a Pluggable Look and Feel
	The MVC Connection
	Components and Containers
	Components
	Containers
	The Top-Level Container Panes
	The Swing Packages
	A Simple Swing Application
	Event Handling
	Create a Swing Applet
	Painting in Swing
	Painting Fundamentals
	Compute the Paintable Area
	A Paint Example
30	Exploring Swing
	JLabel and ImageIcon
	JTextField
	The Swing Buttons
	JButton
	JToggleButton
	Check Boxes
	Radio Buttons
	JTabbedPane
	JScrollPane
	JList
	JComboBox
	Trees
	JTable
	Continuing Your Exploration of Swing
31	Servlets
	Background
	The Life Cycle of a Servlet
	Using Tomcat for Servlet Development
	A Simple Servlet
	Create and Compile the Servlet Source Code
	Start Tomcat
	Start a Web Browser and Request the Servlet
	The Servlet API
	The javax
	The Servlet Interface
	The ServletConfig Interface
	The ServletContext Interface
	The ServletRequest Interface
	The ServletResponse Interface
	The GenericServlet Class
	The ServletInputStream Class
	The ServletOutputStream Class
	The Servlet Exception Classes
	Reading Servlet Parameters
	The javax
	The HttpServletRequest Interface
	The HttpServletResponse Interface
	The HttpSession Interface
	The HttpSessionBindingListener Interface
	The Cookie Class
	The HttpServlet Class
	The HttpSessionEvent Class
	The HttpSessionBindingEvent Class
	Handling HTTP Requests and Responses
	Handling HTTP GET Requests
	Handling HTTP POST Requests
	Using Cookies
	Session Tracking
	Part IV Applying Java
32	Financial Applets and Servlets
	Finding the Payments for a Loan
	The RegPay Fields
	The init( ) Method
	The makeGUI( ) Method
	The actionPerformed( ) Method
	The compute( ) Method
	Finding the Future Value of an Investment
	Finding the Initial Investment Required to Achieve a Future Value
	Finding the Initial Investment Needed for a Desired Annuity
	Finding the Maximum Annuity for a Given Investment
	Finding the Remaining Balance on a Loan
	Creating Financial Servlets
	Converting the RegPay Applet into a Servlet
	The RegPayS Servlet
	Some Things to Try
33	Creating a Download Manager in Java
	Understanding Internet Downloads
	An Overview of the Download Manager
	The Download Class
	The Download Variables
	The Download Constructor
	The download( ) Method
	The run( ) Method
	The stateChanged( ) Method
	Action and Accessor Methods
	The ProgressRenderer Class
	The DownloadsTableModel Class
	The addDownload( ) Method
	The clearDownload( ) Method
	The getColumnClass( ) Method
	The getValueAt( ) Method
	The update( ) Method
	The DownloadManager Class
	The DownloadManager Variables
	The DownloadManager Constructor
	The verifyUrl( ) Method
	The tableSelectionChanged( ) Method
	The updateButtons( ) Method
	Handling Action Events
	Compiling and Running the Download Manager
	Enhancing the Download Manager

The post What to read and What not! – Complete Reference appeared first on Ankit Virparia.

• Explain features of JAVA

• Define polymorphism with its need. Define and explain static and dynamic binding using program.

• Define polymorphism with its need. Define and explain static and dynamic binding using program.

• Ragged Array

• Explain short circuited operators and shift operators.

• Explain short circuited operators, shift operators and this reference.

• Differentiate between constructor and method of class. Define method overloading and its purpose. Write a program to demonstrate the constructor overloading.

• Explain this reference, key word static and garbagecollection.

• Explain Java garbage collection mechanism.

• State whether any error exists in the following code. If so, correct the error andgive output.

  class Test {

  public static void main(String args[]) {

  A a = new A();

  a.print();

  }

  }

  class A {

  String s;

  A(String s) {

  this.s=s;

  }

  public void print() {

  System.out.println(s);

  }

  }

• What is an inner class?

• Define and write a program to differentiate betweenpass by value and pass by reference.

• Explain method overriding and method overloading with the help of examples

• Explain Keyword: Static

• Explain inner class and working of concatenation operator + by giving examples.

• Design a class named Fan to represent a fan. The class contains:- Three constants named SLOW, MEDIUM and FAST with values 1,2 and 3 to

  denote the fan speed.

  – An int data field named speed that specifies the speed of the fan (default

  SLOW).

  – A boolean data field named f_on that specifies whether the fan is on(default

  false).

  – A double data field named radius that specifies the radius of the fan (default

  4).

  – A data field named color that specifies the colorof the fan (default blue).

  – A no-arg constructor that creates a default fan.

  – A parameterized constructor initializes the fan objects to given values.

  – A method named display() will display descriptionfor the fan. If the fan is on, the display() method displays speed, color and radius. If the fan is not on, the method returns fan color and radius along with the message “fan is off”. Write a test program that creates two Fan objects. One with default values and the other with medium speed, radius 6, color brown,and turned on status true. Display the descriptions for two created Fan objects.

• Define the Rectangle class that contains:Two double fields x and y that specify the center of the rectangle, the data field

  width and height , A no-arg constructor that creates the default rectangle with (0,0) for (x,y) and 1 for both width and height. A parameterized constructor creates a rectangle with the specified x,y,height and width.

  A method getArea() that returns the area of the rectangle.

  A method getPerimeter() that returns the perimeter of the rectangle.

  A method contains(double x, double y) that returns true if the specified point

  (x,y) is inside this rectangle.

  Write a test program that creates two rectangle objects. One with default values

  and other with user specified values. Test all the methods of the class for both

  the objects.

• Give output of the following program:public class Test {

  public static void main(String args[]) {

  Count myCount = new Count();

  int times=0;

  for(int i=0;i<100;i++)

  increment(myCount,times);

  System.out.println(“count is “+myCount.count);

  System.out.println(“times is “+times);

  }

  public static void increment(Count c,int times) {

  c.count++;

  times++;

  }

  }

  class Count {

  public int count;

  Count(int c){ count=c; }

  Count(){ count=1; }

  }

• It is required to compute SPI (semester performance index) of n students of your college for their registered subjects in a semester. Declare a class called student having following data members: id_no , no_of_subjects_registered, subject_code , subject_credits, grade_obtained and spi. – Define constructor and calculate_spi methods. – Define main to instantiate an array for objects of class student to process data of n students to be given as command line arguments.

• (i) JVM is platform dependent. Justify. (ii) There is no destructor in Java. Justify.

• Explain single level and multiple inheritances in java. Write a program to demonstrate combination of both types of inheritance as shown in figure 1. i.e.hybrid inheritance

Dec-10 7

• Write a program to demonstrate the multipath inheritance for the classes having relations as shown in figure 2. A->(B,C)->D

Dec-10 7

• Differentiate between abstract class and interface specifying matrices of differences. Write a program to define abstract class, with two methods addition() and subtraction(). addition() is abstract method. Implement the abstract method and call that method using a program(s).

• Explain final and super by giving examples.

• Declare a class called employee having employee_id and employee_name as members. Extend class employee to have a subclass called salary having designation and monthly_salary as members. Define following: – Required constructors – A method to find and display all details of employees drawing salary more than Rs. 20000/-. – Method main for creating an array for storing these details given as command line arguments and showing usage of above methods.

• Explain method overriding and method overloading with the help of examples

• Describe abstractclass called Shapewhich has three subclasses say Triangle,Rectangle,Circle. Define one method area() in the abstract class and override this area()in these three subclasses to calculate for specific object i.e. area() of Triangle subclass should calculate area of triangle etc. Same for Rectangleand Circle

• Explain the followings:(i) Dynamic Method Dispatch with example

  (ii) this, super, final

• State whether the following statements are true or false:(i) The elements in an array must be of primitive data types.

  (ii) When invoking a constructor from a subclass, its super class’s no-arg

  constructor is always invoked.

  (iii) A protected data or method can be accessed by any class in the same

  package.

  (iv) A method can change the length of an array passed as a parameter.

• State whether the following statements are true or false:(i) An abstract class contains constructors.

• Explain Cosmic superclass and its methods

• The abstract Vegetable class has three subclasses named Potato, Brinjal andTomato. Write an application that demonstrates how to establish this class

  hierarchy. Declare one instance variable of type String that indicates the color of

  a vegetable. Create and display instances of these objects. Override the

  toString() method of Object to return a string withthe name of the vegetable

  and its color.

• The abstract Vegetable class has three subclasses named Potato, Brinjal andTomato. Write an application that demonstrates how to establish this class

  hierarchy. Declare one instance variable of type String that indicates the color of

  a vegetable. Create and display instances of these objects. Override the

  toString() method of Object to return a string withthe name of the vegetable

  and its color.

• The Transport interface declares a deliver () method. The abstract class Animal is the super class of the Tiger, Camel, Deer and Donkey classes. The Transport interface is implemented by the Camel and Donkey classes. Write a test program that initialize an array of four Animal objects. If the object implements the Transport interface, the deliver () method is invoked.

• List OOP characteristics and describe inheritance with examples.

• Declare a class called book having author_name as private data member. Extend book class to have two sub classes called book_publication & paper_publication. Each of these classes have private member called title. Write a complete program to show usage of dynamic method dispatch (dynamic polymorphism) to display book or paper publications of given author. Use command line arguments for inputting data.

• Explain super, instanceof and volatile.

• Explain package and interface by giving examples.

• Explain interface in JAVA. How do interfaces support polymorphism?

• Write a program that illustrates interface inheritance. Interface P is extended by P1 and P2. Interface P12inherits from both P1 and P2. Each interface declares one constant and one method. class Q implements P12.Instantiate Q and invoke each of its methods. Each method displays one of the constants

• Explain package in java. List out all packages withshort description

• State whether the following statements are true or false:(i) An interface can extend an abstract class.

• The Transport interface declares a deliver() method. The abstract class Animalis the superclass of the Tiger, Camel, Deer and Donkey classes. The Transport

  interface is implemented by the Camel and Donkey classes. Write a test

  program that initialize an array of four Animal objects. If the object implements

  the Transport interface, the deliver() method is invoked.

• Explain packages, their use, adapter classes and their needs & applications. Give examples.

• Explain interface and its usage.

• Explain the importance of Exception handling in java. Write a program to handle NoSuchMethodException, ArrayIndexOutofBoundsException using try-catch-finally and throw.

• Enlist and explain the difference between error andexception. Write a program to handle InterruptedException, IllegalArgumentException using try-cat-finally and throw.

• Write a method for computing x^y by doing repetitive multiplication. x and y are of type integer and are to be given as command line arguments. Raise and handle exception(s) for invalid values of x and y. Also define method main. Use finally in above program and explain its usage.

• Explain Exception handling in JAVA. Write an application that generates custom exception if any value from its command linearguments is negative.

• Differentiate the followings:(i) Checked and Unchecked Exceptions

  (ii) Constructor and method

  (iii) Text I/O and Binary I/O

• Explain interprocess communication mechanism (wait(), notify() andnotifyall()) being used by java to avoid polling.

• State whether the following statements are true or false:(i) The catch block is the preferred means for releasing resources to prevent resource leaks.

• (ii) Give output of the following program for valueof y=0 and y=2:public class Test {

  public static void main(String args[]) {

  try {

  System.out.println(“calling method a”);

  a();

  System.out.println(“return from method a”);

  } catch(ArithmeticException e) {

  System.out.println(“main: catch”);

  } finally {

  System.out.println(“main: finally”);

  }

  }

  public static void a() {

  try {

  int x=8,y=0;

  int z=x/y;

  System.out.println(“value of z=”+z);

  } catch(NumberFormatException e) {

  System.out.println(“method a:catch”);

  } finally {

  System.out.println(“method a:finally”);

  } }}

• What is  the use following java keywords           
  super, transient, finally, final, static, throw, throws 

• Explain exception handling in JAVA. Write a program that generates custom exception if any integer value given from its command line arguments is negative.

• Explain the importance of exception handling in java. Which key words are used to handle exceptions? Write a program to explain the use of these keywords.

• Explain & illustrate by examples use of final, finally and method finalize.

• Declare a class called coordinate to represent 3 dimensional Cartesian coordinates( x, y and z). Define following methods: – constructor – display, to print values of members – add_coordinates, to add three such coordinate objects to produce a resultant coordinate object. Generate and handle exception if x, y and z coordinates of the result are zero. – main, to show use of above methods.

• Write a program of writing binary file using multithreading. Demonstrate use of join() and yield() interrupt().

• Explain: wait, sleep and synchronize

• Write a complete multi-threaded program to meet following requirements:- Read matrix [A] m x n

  – Create m number of threads

  – Each thread computes summation of elements of one row, i.e. i throw of the matrix is processed by i th thread. Where 0 <= i < m.

  – Print the results.

• It is required to have total two threads, both capable of acting as a produce as well as a consumer. If first thread acts as a producer then, the second thread becomes the consumer and vice-versa. They communicate with each other through a buffer, storing one integer number. One of the threads initiates the communication by sending 1 to the other thread. Thesecond thread, on receiving 1 sends 2 to the first thread. On receiving 2, the first thread sends three integer numbers, one by one to the second thread. The second thread consumes the numbers by displaying them. Both threads terminate after that. Note that both threads must be capable of initiating the communication. Write complete multi-threaded program to meet aboverequirements.

• Why synchronization is required in multithreaded programming and how can we implement it in program?

• Explain Thread Life Cycle in detail. Write a code to create Thread in JAVA.

• Explain the life cycle of a thread.

• What is multithreading? Why it is required? Write a program that creates three threads. Make sure that the main thread executes last.

• Why synchronization is required in multithreaded programming. Write a program that uses thread synchronization to guarantee data integrity in a multithreaded application.

• Write a complete multi-threaded program to meet following requirements: o Two threads of same type are to be instantiated in the method main. o Each thread acts as a producer as well as a consumer. o A shared buffer can store only one integer information along with the source & destination of the information at a time. o The information produced is to be consumed by appropriate consumer. o Both producers produce information for both consumers. o Each thread produces 5 information.

• It is required to add two MxN sized matrices having integer elements to produce a third resultant matrix of size MxN. Write a complete multi-threaded program to meet following requirements: – Accept all required arguments from the command line. – Instantiate M threads – with id 0 to M -1 respectively, each thread performing addition of elements on the row specified by its id to produce corresponding row of the resultant matrix.

• Explain wait, notify, synchronized and native methods.

• Define generics in java. Write a program to demonstrate generic interface and generic method.

• Define generics in java. Write a program to demonstrate generic class and generic constructor.

• Explain Generics in java with demo program.

• What are the benefits of using generic types?

• Illustrate by example – generic programming.

• Differentiate String class and StringBuffer class with explanation of its methods.

• Write a program to add (keyword, URL) list for a web crawler in suitable data structure in concurrent manner but one processat a time, and retrieving data from the data structure in concurrent manner.

• Explain utility class Hashtable and instanceof operator by giving examples.

• State whether the following statements are true or false:(i) If capacity increment is not specified for Vector, the system will double the

  size of Vector each time additional capacity is needed.

• Answer the following questions:(i) Describe the Java Collections Framework. List the interfaces, abstract classes

  and concrete classes of collection hierarchy.

• i) What is collection in Java?  Differentiate between Vector and ArrayList        
  ii)  Explain the unique features of Map interface.

• i) What are generics and how are they used?       ii) Differentiate between Enumeration and Iterator.

• Eplain: utility class Hashtable with example.

• Write a program to create directories (/home/abc/bcd/def/ghi/jkl) in the home directory /home/abc and list the files and directories showing file/directory, file size. Read-write-execute permissions. Write destructor to destroy the data of a class.

• Write a program to replace all “word1” by “word2” from a file1, and output is written to file2 file and display the no. of replacement.

• Write a program to replace all “word1” by “word2” to a file without using temporary file and display the no. of replacement.

• Explain File constructors, any two methods of classFile and method seek.

• Write a program using BufferedInputStream, FileInputStream, BufferedOutputStream, FileOutputStream to copy Content of one file File1.txtinto another file File2.txt.

• Write a program to display the bytes of a file in reverse sequence. Provide the name of the file as a command line argument. (Use RandomAccessFile)

• Write a program that takes input for filename and search word from command-line arguments and checks whether that file exists or not. If exists, the programwill display those lines from a file that contains given search word.

• Write a program that counts the no. of words in a text file. The file name is
  passed as a command line argument. The program should check whether the fileexists or not. The words in the file are separated by white space characters

• Write a program to check that whether the name given from command line is file or not? If it is a file then print the size of file and if it is directory then it should display the name of all files in it.

• Write a program that counts the no. of words in a text file. The file name is passed as a command line argument. The program should check whether the file exists or not. The words in the file are separated by white space characters.

• Compare byte streams and character streams.

• Explain various methods called during execution cycle of the applet. Also explain boarder layout.

• Differentiate Applet and Application.

• Write an applet that contains three buttons OK,CANCEL and HELP and one textfield. if OK is pressed shown on the status bar-“OK is pressed” and the text field should turn red. When CANCEL is pressed -shown on the status bar-“ CANCEL is pressed “and text field should turn green. When HELP is pressed- shown on the status bar-“HELP is pressed” and the text field should turn yellow.

• Explain Applet life cycle with demo program.

• Which methods are called by an applet viewer orbrowser during the lifetime
  of an applet? When are they invoked?

• Differentiate Applet and Application.

• Write an applet that draws four horizontal bars of equal size & of different
  colors such that they cover up the whole applet area. The applet should operate
  correctly even if it is resized.

• Write an applet that tracks the position of the mouse when it is dragged or
  moved. At the current mouse position, it displays message (x, y) showing
  current position of the mouse. The message should disappear as soon as the user
  releases the mouse.

• Differentiate the followings:
  i) Applet and Application ii) String class and StringBuffer class iii) Constructor and Method

• Write an applet that draws four horizontal bars of equal size & of different colors such that they cover up the whole applet area. The applet should operate correctly even if it is resized.

• Write a complete GUI based program to implement a queue of strings in an applet. Select components and layout of your choice.

• Explain life cycle of an applet. Also illustrate how to provide parameters to applet through html.

• Write an event handling program to handle e-mail sending form using your creativity.

• Write an event handling program to handle feedback form of GTU examination system using your creativity.

• Write a program to create a frame with exit capabilities. Handle events for mouse pressed, mouse released, mouse clicked and mouse dragged by displaying appropriate message describing the eventat the coordinates where the event has taken place.

• Explain event handling and different event types ofJava.

• Write a complete program to create a frame for providing GUI to implement a stack for storing integer numbers. There are twobuttons called PUSH & POP and a text field. Clicking of button PUSH pushes the number entered in the text field onto the stack. The click of button POP pops an element from the stack and displays that in the text field.

• Write an applet that contains three buttons OK,CANCEL and HELP and one textfield. if OK is pressed shown on the status bar-“OK is pressed” and the text field should turn red. When CANCEL is pressed -shown on the status bar-“ CANCEL is pressed “and text field should turn green. When HELP is pressed- shown on the status bar-“HELP is pressed” and the text field should turn yellow.

• Explain Event Handling in java and describe methodsof mouse event and key event.

• What is an event source? What are the three responsibilities of eventsources?

• (a) i) What do you mean by Event Delegation model in Java?          ii) How the concept of inner classes is used for event handling?

• (a) i)  Explain the life cycle of an applet ii)  How the concept of adapter classes is used in event handling?  

• Write a program to create a frame with exit capabilities. Handle events for mouse pressed, mouse released, mouse clicked and mouse dragged by displaying appropriate message describing the eventat the coordinates where the event has taken place.

• Write a complete program to create a frame for providing GUI to implement a stack for storing integer numbers. There are twobuttons called PUSH & POP and a text field. Clicking of button PUSH pushes the number entered in the text field onto the stack. The click of button POP pops an element from the stack and displays that in the text field.

• Write a complete program to create a frame for providing GUI to implement a stack for storing integer numbers. There are two buttons called PUSH & POP and a text field. Clicking of button PUSH pushes the number entered in the text field onto the stack. The click of button POP pops an element from the stack and displays that in the text field.

• Write a complete program to have a GUI based simple calculator in a frame supporting addition & subtraction. There are buttons for 0 to 9 digits and for arithmetic operations. Select layout of your choice.

• Name three types of layout managers and briefly explain their operations.

• Explain (i) card layout

• What Is a Java Bean?

• Advantages of Java Beans

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