Given By: Paras Khurana
School: Strawberry Fields
World School
Class: 10-A
Year: 2013-14
I would like to express my special thanks of gratitude to my
teacher Mrs. Smita Satyarthi as well as our principal Mrs.
Sangeeta Sekhon who gave me the golden opportunity to do
this wonderful project on the topic programming in java (movie
ticketing system), which also helped me in doing a lot of
Research and i came to know about so many new things. I am
really thankful to them.
Secondly i would also like to thank my parents and friends who
helped me a lot in finishing this project within the limited time.
And giving me everything I required including the moral support
that I can finish the project on time.
Project Question
1. Data types in java.
2. Decision making statements
3. What are different types of IO
streams? Explain with the help of
examples.
4. Exception handling
5. Build an application that allows an
operator to book the tickets for his
selected movie, book his snacks and
print the bill amount. The bill can be for
matted to display the customer’s details
and the net amount.
CONTENTS
TOPIC
PAGE NO.
INTRODUCTION
1
DATA TYPES IN
JAVA
2-14
DECISION MAKING
STATEMENTS
15-20
IO STREAMS IN
JAVA
21-26
EXCEPTION
HANDLING
27-31
PROGRAM
(MOVIE
TICKETING
SYSTEM
32-47
BIBLIOGRAPHY
48
Introduction
Java is a general-purpose, concurrent, class-based, object-oriented computer programming
language that is specifically designed to have as few implementation dependencies as possible. It is
intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another. Java applications aretypically compiled to bytecode (class file) that can run on any Java virtual machine (JVM) regardless of computer architecture. Java is, as of 2012, one of the most popular programming languages in use, particularly for client-server web applications, with a reported 9 million developers. Java was originally developed by James Gosling at Sun Microsystems (which has since merged into Oracle
Corporation) and released in 1995 as a core component of Sun Microsystems' Java platform. The
language derives much of its syntax from C and C++, but it has fewer low-level facilities than either of them.The original and reference implementation Java compilers, virtual machines, and class libraries were developed by Sun from 1991 and first released in 1995. As of May 2007, in compliance with the
specifications of the Java Community Process, Sun relicensed most of its Java technologies under the GNU General Public License. Others have also developed alternative implementations of these Sun technologies, such as the GNU Compiler for Java (bytecode compiler), GNU Class
path (standard libraries), and IcedTea-Web (browser plugin for applets).
BlueJ is an integrated development environment (IDE) for the Java programming language, developed mainly for educational purposes, but also suitable for small-scale software development. BlueJ was developed to support the learning and teaching of object-oriented programming, and its design differs from other development environments as a result. The main screen graphically shows the class structure of an application under development (in an UML-like diagram), and objects can be interactively created and tested. This interaction facility, combined with a clean, simple user interface, allows easy experimentation with objects under development. Object-oriented concepts (classes, objects, communication through method calls) are represented visually and in its interaction design in the
1.
Data types are predefined by the Java language.
2.
Predefined data types are reserved keyword so we cannot use them as variable
name inside program/application.
3.
Primitive values do not share state with other primitive values.
4.
Total Number of Primitive Data Types in Java Programming is 8.
5.
All Primitive Data Types have respective Wrapper Classes i.e. Integer is wrapper
class for primitive type int.
Data Types:
Type
Contains
Default
Size
Boolean
true or false
false
1 bit
char
Unicode Character
u0000
16 bits
byte
Signed Integer
0
8 bits
short
Signed Integer
0
16 bits
int
Signed Integer
0
32 bits
long
Signed Integer
0
64 bits
float
Floating Number
0.0
32 bit
Integer Data Types:
1. Integer Data Type is used to store integer value.
2. Integer Data Type is Primitive Data Type in Java Programming Language.
3. Integer Data Type have respective Wrapper Class – “Integer“.
4. Integer Data Type is able to store both unsigned and signed integer values so Java
opted signed, unsigned concept of C/C++.
Integer Data Type can have 4 types of Values these are listed
below in the table
-Name Width Range
long
64
–9,223,372,036,854,775,808 to
9,223,372,036,854,775,807
int
32
–2,147,483,648 to 2,147,483,647
short
16
–32,768 to 32,767
byte
8
–128 to 127
5. Literals for integers consist of a sequence of digits. Most programming languages
disallow use of commas for digit grouping, although Fortran (77, 90, and above,
fixed form source but not free form source) allows embedded spaces,
and Perl, Ruby, Java and D allow embedded underscores. Negation is indicated by
a minus sign (−) before the value. Examples of integer literals are:
42
10000
Example: Declaring Integer Variable in Java
Programming
Class IntDemo
{
Public
static
void
main
(String
args
[])
{
int
number
=0
;
System
.
out
.
println
("
Number:
"
+
number
)
;
}
}
Explanation:
1.
Primitive Variable can be declared using “int” keyword.
2. Though Integer contain default Initial Value as 0, still we have assign 0 to show
assignment in Java.
3.
“+” operator is used to concatenate 2 strings.
4. Integer is converted into String internally and then two strings are concatenated.
Floating-Point Data Type:
1. Floating Data Type is used to store float value.
2. Floating Data Type is Primitive Data Type in Java Programming Language.
3. Floating Data Type have respective Wrapper Class – “Float or Double“.
Float Data Type Can store 2 types of Values these are listed below -
1. Float
2. Double
float
Variables of this type can have values from -3.4E38 (-3.4 * 1038) to +3.4E38
(+3.4 * 1038) and occupy 4 bytes in memory. Values are represented with
approximately 7 decimal digits accuracy
double Variables of this type can have values from -1.7E308 (-1.7 * 10308) to
+1.7E308 (+1.7 * 10308) and occupy 8 bytes in memory. Values are
represented with approximately 17 decimal digits accuracy. The smallest
non-zero value that you can have is roughly (4.9 * 10–324).
Example : Declaring float Variable in Java Programming
Class FloatDemo
{
public
static
void
main
(
String
args
[])
{
float
fval
=
10.0f
;
System
.
out
.
println
(
"
Total Number :
"
+
fval
)
;
}
}
Float Type : Some Notes
In Java any value declared with decimal point is by default of type double.
Suppose we have to assign float value then we must use „f‟ or „F‟ literal to
specify that current value is “Float”.
Specify “E” or “e” for values which contain exponent.
How to Declare float Variable
How to Declare Double Variable
Class FloatDemo
{
public
static
void
main
(
String
args
[])
{
double
d1
=
10
;
System
.
out
.
println
(
"
Total Number :
"
+
fval
)
;
}
}
We have assigned integer value to the Double . (i.e we are assigning lower
value of inside bigger variable , no need to typecast )
double keyword is used to declare double variable.
Character Data Types:
1. In Java, the data type used to store characters is char.
2. Character is 16 bits wide in Java.
3. Java uses Unicode to represent characters.
4. Java support lot of Unicode symbols from many more human languages for this
purpose, it requires 16 bits.
5. The range of a char is 0 to 65,536.
6. There are no negative chars.
What is Unicode ?
Unicode defines a fully international character set that can represent all of the
characters found in all human languages.
Example 1 : Integer Value Assigned to Character Data Type
public
static
void
main
(
String
args
[])
{
char
ch
;
ch
=
'M'
;
System
.
out
.
println
(
"
Character is :
"
+
ch
)
;
}
}
Output :
Character is
:
M
Example 2 : Integer Value Assigned to Character Data Type
// Demonstrate char data type.
class
CharDemo
{
public
static
void
main
(
String
args
[])
{
char
ch1
,
ch2
;
ch1
=
88
;
// code for X
ch2
=
'Y'
;
System
.
out
.
(
"
ch1 and ch2:
"
)
;
System
.
out
.
println
(
ch1
+
""
+
ch2
)
;
}
}
Output :
ch1
and
ch2
:
X Y
Example 3 : Incrementing Character Variable
class
CharDemo2
{
public
static
void
main
(
String
args
[])
{
char
ch1
;
System
.
out
.
println
(
"
ch1 contains
"
+
ch1
)
;
ch1
++
;
// increment ch1
System
.
out
.
println
(
"
ch1 is now
"
+
ch1
)
;
}
}
Output :
ch1 contains P
ch1 is now Q
Boolean Data Type :
1. Boolean is
primitive data type in Java
.
2. Boolean data type is used for
logical values
.
3. Boolean data type can have two possible values :
true or false
.
4. Boolean is the type
returned by all relational operators
5. Boolean is the type required
by the conditional expressions
used in control
statements such as if and for.
6.
“Boolean” is wrapper class for “boolean” primitive data type.
How to Declare & Display Boolean Variable ?
public
static
void
main
(
String
args
[])
{
boolean b1
,
b2
,
b3
;
b1
=
true
;
// Assigning Value
b2
=
false
;
// Assigning Value
b3
=
b2
;
// Assigning Variable
System
.
out
.
println
(
b1
)
;
// Printing Value
System
.
out
.
println
(
b2
)
;
// Printing Value
System
.
out
.
println
(
b3
)
;
// Printing Value
}
Output:
true
false
false
Different Ways of Using Boolean Value :
Way 1 : Inside If Statement
Boolean Value is used to check whether condition is true or not.
public
static
void
main
(
String
args
[])
{
boolean b
;
b
=
true
;
if
(
b
==
true
)
{
System
.
out
.
println
(
"
I am True
"
)
;
}
}
Way 2 : Comparing Two Numbers
class
Demo
{
public
static
void
main
(
String
args
[])
{
boolean b
;
b
=
(
10
>
6
)
;
if
(
b
)
System
.
out
.
println
(
"
10 > 6
"
)
;
}
}
}
We can use boolean value to hold the result Comparison operators. Here 10 >
6 therefore true will be stored in boolean variable
In Java a reference data type is a variable that can contain the reference or an
address of dynamically created object. These type of data type are not predefined
like primitive data type. The reference data types
are arrays, classes and interfaces that are made and handle according to a
programmer in a java program which can hold the three kind of values as:
class type:
As you know that Java is an object-oriented programming language where an object is
a variable, associated with methods that is described by a class. The name of a class is
treated as a type in a java program, so that you can declare a variable of an
object-type, and a method which can be called using that object- type variable.
array type
// Points to an array instance
class type
// Points to an object or a class instance
interface type
// Points to an object and a method, which is
implemented to the corresponding interface
Whenever a variable is created, a reference to an object is also created using the name
of a class for its type i.e. that variable can contain either null or a reference to an object
of that class. It is not allowed to contain any other kinds of values. Such type is
called reference types in Java. The object becomes an instance when the memory is
allocated to that object using new keyword. In addition, array typesare reference
types because these are treated as objects in Java. For example:
class Fruit {
fColor(){....}
fSize(){....}
};Fruit mango;
Fruit banana;
...
In the given example the Fruit is a class that has the reference variables as mango &
banana through which we can call
the behaviors associated with that class as mango.fColor(); within the main method of
the super class.
Array Type:
An array is a special kind of object that contains values called elements. The java
array enables the user to store the values of the same type in contiguous memory
allocations. The elements in an array are identified by an integer index which initially
starts from 0 and ends with one less than number of elements available in the array.
All elements of an array must contain the same type of value i.e. if an array is a type of
integer then all the elements must be of integer type. It is areference data
type because the class named as Array implicitly extendsjava.lang.Object. The
DataType [] variable1,
variable2, ...variableN;
DataType [] variable = new
DataType [ArraySize];
DataType [] variable = {item 1,
item 2,...item n};
For example:
int [] a = new int [10];
String [] b =
{"reference","data",
"type"};
In the first statement, an array variable "a" is declared of integer data type that holds
the memory spaces according to the size of int. The index of the array starts
from a[0] and ends with a[9]. Thus, the integer value can be assigned for each or a
particular index position of the array.
In the second statement, the array "b" is declared of string data type that has the
enough memory spaces to directly holds the three string values. Thus each value is
assigned for each index position of the array.
Interface Type:
Java provides an another kind of reference data type or a mechanism to
support multiple inheritance feature called an interface. The name of an interface
can be used to specify the type of a reference. A value is not allowed to be assign to a
variable declared using an interface type until theobject implements the
When a class declaration implements an interface, that class inherits all of the variables
and methods declared in that interface. So the implementations for all of the methods
declared in the interface must be provided by that class. For example, Java provides an
interface called ActionListener whose method named actionPerformed() is used to
handle the different kind of event . Java also provides a class called Thread that
implements Runnable interface.
Thus the following assignment can be allowed:
Runnable r;
r = new
Thread();
There are two types of decision making statements in Java. They are:
if statements
switch statements
The if Statement:
A if statement consists of a Boolean expression
followed by one or more statements.
Syntax:
The syntax of a if statement is:
if(Boolean_expression) {
//Statements will execute if the Boolean
expression is true }
If the Boolean expression evaluates to true then the
block of code inside the if statement will be executed. If not the first set of code after the
end of the if statement (after the closing curly brace) will be executed.
Example:
public class Test {
public static void main(String args[]){ int x = 10;
if( x < 20 ) {
System.out.print("This is if statement"); }
} }
This is if statement
The if...else Statement:
An if statement can be followed by an
optional
else
statement, which executes when the
Boolean expression is false.
Syntax:
The syntax of an if...else is:
if(Boolean_expression) {//Executes when the Boolean expression is
true }else {
//Executes when the Boolean expression is
false }
Example:
public class Test {
public static void main(String args[]){ int x = 30;
if( x < 20 ){
System.out.print("This is if statement"); }else{
System.out.print("This is else statement"); }
} }
This would produce the following result:
This is else statement
The if...else if...else
Statement:
An if statement can be followed by an
optional
else if...else
statement, which is very
useful to test various conditions using single
if...else if statement.
When using if , else if , else statements there are few points to keep in mind.
An if can have zero or one else's and it must come after any else if's.
An if can have zero to many else if's and they must come before the else.
Once an else if succeeds, none of the remaining else if's or else's will be tested.
Syntax:
The syntax of an if...else…if is:
if(Boolean expression 1) {//Executes when the Boolean expression 1 is true
}
else if(Boolean expression 2) {
//Executes when the Boolean expression 2 is true
}
else if(Boolean expression 3) {
//Executes when the Boolean expression 3 is true
} else {
//Executes when the none of the above condition is true.
}
Example:
public class Test {
public static void main(String args[]) {
int x = 30; if( x == 10 ) {
System.out.print("Value of X is 10"); }
else if( x == 20 ) {
System.out.print("Value of X is 20"); }
else if( x == 30 ) {
System.out.print("Value of X is 30"); }
else {
System.out.print("This is else statement"); }
} }
This would produce the following result:
Value of X is 30
Nested if...else Statement:
It is always legal to nest if-else statements which means you can use one if or else if
statement inside another if or else if statement.
Syntax:
The syntax for a nested if...else is as follows:
if(Boolean_expression 1){
//Executes when the Boolean expression 1 is true
if(Boolean_expression 2) {
//Executes when the Boolean expression 2 is true }
}
You can nest
else if...else
in the similar way as we have nested
if
statement.
Example:
public class Test {
public static void main(String args[]){ int x = 30;
int y = 10; if( x == 30 ){ if( y == 10 ){
System.out.print("X = 30 and
Y = 10");
} } } }
This would produce the following result:
X = 30 and Y = 10A
switch
statement allows a variable to be tested for equality against a list of values.
Each value is called a case, and the variable being switched on is checked for each
case.
Syntax:
The syntax of switch is:
switch(expression) { case value : //Statements break; //optional case value : //Statements break; //optional//You can have any number of case statements.
default : //Optional //Statements }
The following rules apply to a switch statement:
The variable used in a switch statement can only be a byte, short, int, or char.
You can have any number of case statements within a switch. Each case is followed by
the value to be compared to and a colon.
The value for a case must be the same data type as the variable in the switch and it
must be a constant or a literal.
When the variable being switched on is equal to a case,
the statements following that case will execute until
a
break
statement is reached.
When a
break
statement is reached, the switch
terminates, and the flow of control jumps to the next line
following the switch statement.
Not every case needs to contain a break. If no break
appears, the flow of control will
fall through
to subsequent
cases until a break is reached.
A
switch
statement can have an optional default case,
which must appear at the end of the switch. The default
case can be used for performing a task when none of the
cases is true. No break is needed in the default case.
The java.io package contains class needed to perform input and output (I/O) in Java. All
these streams represent an input source and an output destination. The stream in the
java.io package supports many data such as primitives, Object, localized characters,
etc.
A stream can be defined as a sequence of data. The InputStream is used to read data
from a source and the OutputStream is used for writing data to a destination.
Java does provide strong, flexible support for I/O as it relates to files and networks.
Reading Console Input:
Java input console is accomplished by reading from
System.in
. To obtain a
character-based stream that is attached to the console, you wrap
System.in
in
a
BufferedReader
object, to create a character stream. Here is most common syntax to
obtain BufferedReader:
BufferedReader
br =
new
BufferedReader
(
new
InputStreamReader
(
System
.
in
));
Once BufferedReader is obtained, we can use read( ) method to reach a character or
readLine( ) method to read a string from the console.
Reading Characters from Console:
To read a character from a BufferedReader, we would read( ) method whose sytax is as
follows:
int
read( )
throws
IOException
Each time that read( ) is called, it reads a character from the input stream and returns it
as an integer value. It returns .1 when the end of the stream is encountered. As you can
see, it can throw an IOException.
The following program demonstrates read( ) by reading characters from the console
until the user types a "q":
import
java.io.*;
public
class
BRRead
{
public
static
void
main(
String
args[])
throws
IOException
{
char
c;
// Create a BufferedReader using System.in
BufferedReader
br =
new
BufferedReader
(
new
InputStreamReader
(
System
.
in
));
System
.
out
.println(
"Enter characters, 'q' to quit."
);
// read characters
do
{
c = (
char
) br.read();
System
.
out
.println(c);
}
while
(c !=
'q'
);
}
}
Here is a sample run:
Enter
characters,
'q'
to quit.
123abcq
1
2
3
a
b
c
q
Reading Strings from Console:
To read a string from the keyboard, use the version of readLine( ) that is a member of
the BufferedReader class. Its general form is shown here:
String
readLine( )
throws
IOException
The following program demonstrates BufferedReader and the readLine( ) method. The
program reads and displays lines of text until you enter the word "end":
// Read a string from console using a BufferedReader.
import
java.io.*;
public
class
BRReadLines
{
public
static
void
main(
String
args[])
throws
IOException
{
BufferedReader
br =
new
BufferedReader
(
new
InputStreamReader
(
System
.
in
));
String
str;
System
.
out
.println(
"Enter lines of text."
);
System
.
out
.println(
"Enter 'end' to quit."
);
do
{
str = br.readLine();
System
.
out
.println(str);
}
while
(!str.equals(
"end"
));
}
}
Here is a sample run:
Enter
lines of text.
Enter
'end'
to quit.
This
is
line one
This
is
line one
This
is
line two
This
is
line two
end
end
Writing Console Output:
Console output is most easily accomplished with
print( )
and
println( )
, described
earlier. These methods are defined by the class
PrintStream
which is the type of the
object referenced by
System.out
. Even though System.out is a byte stream, using it for
simple program output is still acceptable.
Reading and Writing Files:
Here is a hierarchy of classes to deal with Input and Output streams.
The two important streams are FileInputStream and FileOutputStream,
File Input Stream:
This stream is used for reading data from the files. Objects can be created using the
keyword new and there are several types of constructors available.
Following constructor takes a file name as a string to create an input stream object to
read the file.:
InputStream
f =
new
FileInputStream
(
"C:/java/hello"
);
Following constructor takes a file object to create an input stream object to read the file.
First we create a file object using File() method as follows:
File
f =
new
File
(
"C:/java/hello"
);
InputStream
f =
new
FileInputStream
(f);
Once you have
InputStream
object in hand, then there is a list of helper methods which
can be used to read to stream or to do other operations on the stream.
1
public void close() throws IOException{}
This method closes the file output stream. Releases any system resources
associated with the file. Throws an IOException.
2
protected void finalize()throws IOException {}
This method cleans up the connection to the file. Ensures that the close method
of this file output stream is called when there are no more references to this
stream. Throws an IOException.
3
public int read(int r)throws IOException{}
This method reads the specified byte of data from the InputStream. Returns an
int. Returns the next byte of data and -1 will be returned if it's end of file.
4
public int read(byte[] r) throws IOException{}
This method reads r.length bytes from the input stream into an array. Returns the
total number of bytes read. If end of file -1 will be returned.
5
public int available() throws IOException{}
Gives the number of bytes that can be read from this file input stream. Returns an
int.
File Output Stream:
FileOutputStream is used to create a file and write data into it. The stream would create
a file, if it doesn't already exist, before opening it for output.
Here are two constructors which can be used to create a FileOutputStream object.
Following constructor takes a file name as a string to create an input stream object to
write the file:
OutputStream
f =
new
FileOutputStream
(
"C:/java/hello"
)
Following constructor takes a file object to create an output stream object to write the
file. First, we create a file object using File() method as follows:
File
f =
new
File
(
"C:/java/hello"
);
OutputStream
f =
new
FileOutputStream
(f);
Once you have
OutputStream
object in hand, then there is a list of helper methods,
which can be used to write to stream or to do other operations on the stream.
SN Methods with Description
1
public void close() throws IOException{}
This method closes the file output stream. Releases any system resources
associated with the file. Throws an IOException.
This method cleans up the connection to the file. Ensures that the close method
of this file output stream is called when there are no more references to this
stream. Throws an IOException.
3
public void write(int w)throws IOException{}
This methods writes the specified byte to the output stream.
4
public void write(byte[] w)
Writes w.length bytes from the mentioned byte array to the OutputStream.
Example:
Following is the example to demonstrate InputStream and OutputStream:
import
java.io.*;
public
class
fileStreamTest{
public
static
void
main(
String
args[]){
try
{
byte
bWrite [] = {11,21,3,40,5};
OutputStream
os =
new
FileOutputStream
(
"test.txt"
);
for
(
int
x=0; x < bWrite.length ; x++){
os.write( bWrite[x] );
// writes the bytes
}
os.close();
InputStream
is
=
new
FileInputStream
(
"test.txt"
);
int
size =
is
.available();
for
(
int
i=0; i< size; i++){
System
.
out
.
((
char
)
is
.read() +
" "
);
}
is
.close();
}
catch
(
IOException
e){
System
.
out
.
(
"Exception"
);
}
}
}
The above code would create file test.txt and would write given numbers in binary
format. Same would be output on the stdout screen.
An exception is a problem that arises during the execution of a program. An exception
can occur for many different reasons, including the following:
A user has entered invalid data.
A file that needs to be opened cannot be found.
A network connection has been lost in the middle of communications or the JVM has
run out of memory.
Some of these exceptions are caused by user error, others by programmer error, and
others by physical resources that have failed in some manner.
Categories of exceptions:
Checked exceptions:
A checked exception is an exception that is typically a user error
or a problem that cannot be foreseen by the programmer. For example, if a file is to be
opened, but the file cannot be found, an exception occurs. These exceptions cannot
simply be ignored at the time of compilation.
Runtime exceptions:
A runtime exception is an exception that occurs that probably
could have been avoided by the programmer. As opposed to checked exceptions,
runtime exceptions are ignored at the time of compilation.
Errors:
These are not exceptions at all, but problems that arise beyond the control of
the user or the programmer. Errors are typically ignored in your code because you can
rarely do anything about an error. For example, if a stack overflow occurs, an error will
arise. They are also ignored at the time of compilation.
Catching Exceptions:
A method catches an exception using a combination of the
try
and
catch
keywords. A
try/catch block is placed around the code that might generate an exception. Code within
a try/catch block is referred to as protected code, and the syntax for using try/catch
looks like the following:
try
{
//Protected code
}
catch
(
ExceptionName
e1)
{
//Catch block
}
A catch statement involves declaring the type of exception you are trying to catch. If an
exception occurs in protected code, the catch block (or blocks) that follows the try is
checked. If the type of exception that occurred is listed in a catch block, the exception is
passed to the catch block much as an argument is passed into a method parameter.
Example:
The following is an array is declared with 2 elements. Then the code tries to access the
3rd element of the array which throws an exception.
// File Name : ExcepTest.java
import
java.io.*;
public
class
ExcepTest
{
public
static
void
main(
String
args[]){
try
{
int
a[] =
new
int
[2];
System
.
out
.println(
"Access element three :"
+ a[3]);
}
catch
(
ArrayIndexOutOfBoundsException
e){
System
.
out
.println(
"Exception thrown :"
+ e);
}
System
.
out
.println(
"Out of the block"
);
}
}
This would produce the following result:
Exception
thrown :java.lang.
ArrayIndexOutOfBoundsException
: 3
Out
of the block
Multiple catch Blocks:
A try block can be followed by multiple catch blocks. The syntax for multiple catch
blocks looks like the following:
try
{
}
catch
(
ExceptionType1
e1)
{
//Catch block
}
catch
(
ExceptionType2
e2)
{
//Catch block
}
catch
(
ExceptionType3
e3)
{
//Catch block
}
The previous statements demonstrate three catch blocks, but you can have any number
of them after a single try. If an exception occurs in the protected code, the exception is
thrown to the first catch block in the list. If the data type of the exception thrown
matches ExceptionType1, it gets caught there. If not, the exception passes down to the
second catch statement. This continues until the exception either is caught or falls
through all catches, in which case the current method stops execution and the
exception is thrown down to the previous method on the call stack.
Example:
Here is code segment showing how to use multiple try/catch statements.
try
{
file =
new
FileInputStream
(fileName);
x = (
byte
) file.read();
}
catch
(
IOException
i)
{
i.printStackTrace();
return
-1;
}
catch
(
FileNotFoundException
f)
//Not valid!
{
f.printStackTrace();
return
-1;
}
The throws/throw Keywords:
If a method does not handle a checked exception, the method must declare it using
the
throws
keyword. The throws keyword appears at the end of a method's signature.
You can throw an exception, either a newly instantiated one or an exception that you
just caught, by using the
throw
keyword. Try to understand the different in throws and
throw keywords.
import
java.io.*;
public
class
className
{
public
void
deposit(
double
amount)
throws
RemoteException
{
// Method implementation
throw
new
RemoteException
();
}
//Remainder of class definition
}
A method can declare that it throws more than one exception, in which case the
exceptions are declared in a list separated by commas. For example, the following
method declares that it throws a RemoteException and an InsufficientFundsException:
import
java.io.*;
public
class
className
{
public
void
withdraw(
double
amount)
throws
RemoteException
,
InsufficientFundsException
{
// Method implementation
}
//Remainder of class definition
}
The finally Keyword
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.
Using a finally block allows you to run any cleanup-type statements that you want to
execute, no matter what happens in the protected code.
A finally block appears at the end of the catch blocks and has the following syntax:
try
{
//Protected code
}
catch
(
ExceptionType1
e1)
{
//Catch block
}
catch
(
ExceptionType2
e2)
{
//Catch block
}
catch
(
ExceptionType3
e3)
{
//Catch block
}
finally
{
//The finally block always executes.
}
Example:
public
class
ExcepTest
{
public
static
void
main(
String
args[]){
int
a[] =
new
int
[2];
try
{
System
.
out
.println(
"Access element three :"
+ a[3]);
}
catch
(
ArrayIndexOutOfBoundsException
e){
System
.
out
.println(
"Exception thrown :"
+ e);
}
finally
{
a[0] = 6;
System
.
out
.println(
"First element value: "
+a[0]);
System
.
out
.println(
"The finally statement is
executed"
);
}
}
}
This would produce the following result:
Exception
thrown :java.lang.
ArrayIndexOutOfBoundsException
: 3
First
element value: 6
The
finally
statement
is
executed
Note the following:
A catch clause cannot exist without a try statement.
It is not compulsory to have finally clauses when ever a try/catch block is present.
The try block cannot be present without either catch clause or finally clause.
The Java Project Program
(Movie Ticketing System)
import java.io.*;
public class movies
{
static double bill;
static int c,type,d,flag;
static int e,type1,f;
static int g,type2,h; //Initialising all the required variables
static int i,type3,j;
static int quan;
static String l,n[],k;
static int m;
static String s,s1,s2,s3;
public static void main(String [] args)throws IOException
{
String a,b;String ch="";
String n[]=new String[4];
n[0]="burger";
n[1]="nachos";
n[2]="coke";
n[3]="popcorn";
BufferedReader buf=new BufferedReader(new
InputStreamReader(System.in));
do
{
System.out.println("--- WELCOME TO FUN CINEMAS ONLINE
BOOKING COUNTER ---");
System.out.println(" PLEASE SELECT THE MOVIE YOU WOULD LIKE TO
WATCH: ");
System.out.println("\n");
System.out.println("1. IRON MAN 3 ");
System.out.println("2. FAST AND FURIOUS 6 ");
System.out.println("3. GO GOA GONE "); //Here the movie is being selected
System.out.println("4. MAN OF STEEL "); System.out.println("\n");
System.out.println("TYPE THE NAME OF THE MOVIE YOU WANT TO WATCH IN CAPILTAL LETTERS");
try {
ch=buf.readLine(); //an expected error that the user enters something else instead of the movie
catch(IOException e1) {
System.out.println("Movie not running"); //handling of the exception }
if(ch.equalsIgnoreCase("IRON MAN 3")) {
System.out.println("\nPROCESSING YOUR REQUEST"); for(int z=0;z<1000000000;z++) { } System.out.println("\f"); IM3(); }
if(ch.equalsIgnoreCase("FAST AND FURIOUS 6")) {
System.out.println("\nPROCESSING YOUR REQUEST"); for(int z=0;z<1000000000;z++)
{ }
System.out.println("\f"); //calling of the function corresponding to the movie selected
FAF6(); }
if(ch.equalsIgnoreCase("GO GOA GONE")) {
System.out.println("\nPROCESSING YOUR REQUEST"); for(int z=0;z<1000000000;z++) { } System.out.println("\f"); GGG(); } if(ch.equalsIgnoreCase("MAN OF STEEL")) {
System.out.println("\nPROCESSING YOUR REQUEST"); for(int z=0;z<1000000000;z++) { } System.out.println("\f"); MOS(); } System.out.println("\n\n");
System.out.println("DO YOU WANT TO BOOK SOME SNACKS:"); System.out.println("\n\n");
System.out.println("TYPE 'Y' FOR YES OR PRESS ANY OTHER KEY"); a=buf.readLine();
System.out.println("\nPROCESSING YOUR REQUEST"); for(int z=0;z<1000000000;z++)
{ }
System.out.println("\f");
if(a.equalsIgnoreCase("y")) //checking whether the user wants to buy some snacks or not
{
SNACKS(); }
System.out.println("\n\n");
System.out.println("*** **** ***** COPY OF THE RECIEPT IS: ***** **** ***"); System.out.println("MOVIE: "+ch);
System.out.println("NO. OF TICKETS: "+d); //displaying of the bill
do {
System.out.print("THE SNACKS BOOKED ARE: "); for(m=0;m<1;m++) { if(s.equalsIgnoreCase(n[m])) { flag=0; System.out.print(n[m]); break; } } for(m=1;m<2;m++) { if(s1.equalsIgnoreCase(n[m])) { flag=0; System.out.print(", "+n[m]); break; } } for(m=2;m<3;m++) { if(s2.equalsIgnoreCase(n[m])) { flag=0; System.out.print(", "+n[m]); break; } } for(m=3;m<4;m++) { if(s3.equalsIgnoreCase(n[m])) { flag=0; System.out.println(", "+n[m]); break; } } }while(flag!=0); System.out.println("\nPAY Rs. "+bill);
System.out.println("~~~~~~~~~~ TYHANK YOU FOR WATHCHING MOVIES WITH FUN CINEMAS ~~~~~~~~~~");
System.out.println("DO YOU WANT TO BOOK TICKET FOR ANY OTHER MOVIE:"); System.out.println("\n\n");
System.out.println("TYPE 'Y' FOR YES OR PRESS ANY OTHER KEY"); //checking whether the user wants to buy any tother movie ticket or not b=buf.readLine();
}
while(b.equalsIgnoreCase("y")); }
public static void IM3()throws IOException {
BufferedReader buf=new BufferedReader(new InputStreamReader(System.in));
System.out.println("--- WHAT TIMING OF THE MOVIE IRON MAN 3 DO YOU WANT TO BOOK ---");
System.out.println("\n\n");
System.out.println("ENTER: \n 1. for 8:00 am \n 2. for 11:00 am \n 3. for 2:00 pm \n 4. for 5:00 pm \n 5. for 9:00 pm"); try { c=Integer.parseInt(buf.readLine()); } catch(IOException e1) { System.out.println("invalid entry"); }
System.out.println("WHICH CLASS WOULD YOU LIKE TO BOOK:"); System.out.println("\n\n");
System.out.println(" 1.BUSSINESS\n 2.GOLD\n 3.SILVER\n 4.BRONZE"); try { type=Integer.parseInt(buf.readLine()); } catch(IOException e1) { System.out.println("invalid entry"); } switch(type) { case 1:
System.out.println("THE PRICE IS Rs.500 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); d=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+d*500); bill=bill+(d*500);
break; case 2:
System.out.println("THE PRICE IS Rs.250 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); d=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+d*250); bill=bill+(d*250);
break; case 3:
System.out.println("THE PRICE IS Rs.175 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); d=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+d*175); bill=bill+(d*175);
break; case 4:
System.out.println("THE PRICE IS Rs.100 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); d=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+d*100); bill=bill+(d*100); break; default: System.out.println("INVALID ENTRY"); } }
public static void FAF6()throws IOException {
BufferedReader buf=new BufferedReader(new InputStreamReader(System.in));
System.out.println("--- WHAT TIMING OF THE MOVIE FAST AND FURIOUS 6 DO YOU WANT TO BOOK ---");
System.out.println("\n\n");
System.out.println("ENTER: \n 1. for 8:30 am \n 2. for 11:30 am \n 3. for 2:30 pm \n 4. for 5:30 pm \n 5. for 9:30 pm"); try { e=Integer.parseInt(buf.readLine()); } catch(IOException e1) { System.out.println("invalid entry"); }
System.out.println("WHICH CLASS WOULD YOU LIKE TO BOOK:"); System.out.println("\n\n");
System.out.println(" 1.BUSSINESS\n 2.GOLD\n 3.SILVER\n 4.BRONZE"); try { type1=Integer.parseInt(buf.readLine()); } catch(IOException e1) { System.out.println("invalid entry"); } switch(type1) { case 1:
System.out.println("THE PRICE IS Rs.500 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); f=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+f*500); bill=bill+(f*500);
break; case 2:
System.out.println("THE PRICE IS Rs.250 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); f=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+f*250); bill=bill+(f*250);
break; case 3:
System.out.println("THE PRICE IS Rs.175 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); f=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+f*175); bill=bill+(f*175);
break; case 4:
System.out.println("THE PRICE IS Rs.100 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); f=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+f*100); bill=bill+(f*100); break; default: System.out.println("INVALID ENTRY"); } }
public static void GGG()throws IOException {
BufferedReader buf=new BufferedReader(new InputStreamReader(System.in));
System.out.println("--- WHAT TIMING OF THE MOVIE GO GOA GONE DO YOU WANT TO BOOK ---");
System.out.println("\n\n");
System.out.println("ENTER: \n 1. for 9:00 am \n 2. for 12:00 am \n 3. for 3:00 pm \n 4. for 6:00 pm \n 5. for 10:00 pm"); try { g=Integer.parseInt(buf.readLine()); } catch(IOException e1) { System.out.println("invalid entry"); }
System.out.println("WHICH CLASS WOULD YOU LIKE TO BOOK:"); System.out.println("\n\n");
System.out.println(" 1.BUSSINESS\n 2.GOLD\n 3.SILVER\n 4.BRONZE"); try { type2=Integer.parseInt(buf.readLine()); } catch(IOException e1) { System.out.println("invalid entry"); } switch(type2) { case 1:
System.out.println("THE PRICE IS Rs.500 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); h=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+h*500); bill=bill+(h*500);
break; case 2:
System.out.println("THE PRICE IS Rs.250 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); h=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+h*250); bill=bill+(h*250);
break; case 3:
System.out.println("THE PRICE IS Rs.175 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); h=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+h*175); bill=bill+(h*175);
break; case 4:
System.out.println("THE PRICE IS Rs.100 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); h=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+h*100); bill=bill+(h*100); break; default: System.out.println("INVALID ENTRY"); } }
public static void MOS()throws IOException {
BufferedReader buf=new BufferedReader(new InputStreamReader(System.in));
System.out.println("--- WHAT TIMING OF THE MOVIE MAN OF STEEL DO YOU WANT TO BOOK ---");
System.out.println("\n\n");
System.out.println("ENTER: \n 1. for 9:30 am \n 2. for 12:30 am \n 3. for 3:30 pm \n 4. for 6:30 pm \n 5. for 10:30 pm"); try { i=Integer.parseInt(buf.readLine()); } catch(IOException e1) { System.out.println("invalid entry"); }
System.out.println("WHICH CLASS WOULD YOU LIKE TO BOOK:"); System.out.println("\n\n");
System.out.println(" 1.BUSSINESS\n 2.GOLD\n 3.SILVER\n 4.BRONZE"); try
{
} catch(IOException e1) { System.out.println("invalid entry"); } switch(type3) { case 1:
System.out.println("THE PRICE IS Rs.500 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); j=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+j*500); bill=bill+(j*500);
break; case 2:
System.out.println("THE PRICE IS Rs.250 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); j=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+j*250); bill=bill+(j*250);
break; case 3:
System.out.println("THE PRICE IS Rs.175 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); j=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+j*175); bill=bill+(j*175);
break; case 4:
System.out.println("THE PRICE IS Rs.100 PER TICKET"); System.out.println("\n\n");
System.out.println("ENTER THE NO. OF TICKETS"); j=Integer.parseInt(buf.readLine());
System.out.println("THE AMT OF THE TICKETS= "+j*100); bill=bill+(j*100); break; default: System.out.println("INVALID ENTRY"); } }
public static void SNACKS()throws IOException {
String n[]=new String[4]; n[0]="burger";
n[1]="nachos"; n[2]="coke"; n[3]="popcorn";
BufferedReader buf=new BufferedReader(new InputStreamReader(System.in));
System.out.println("--- WHICH SNACK WOULD YOU LIKE TO BOOK ---"); System.out.println("\n\n");
System.out.println("ENTER THE NAME OF THE SNACK IN THE ABOVE MENTIONED ORDER,\nNOTE: AFTER WRITING THE NAME OF THE SSNACK HIT ENTER AND IF YOU DO NOT WANT TO BUY ANY SNACK THEN HIT ENTER AND TYPE THE NEXT SNACK");
try { s=buf.readLine(); } catch(NumberFormatException e1) { System.out.println("INVALID ENTRY"); } try { s1=buf.readLine(); } catch(NumberFormatException e1) { System.out.println("INVALID ENTRY"); } try { s2=buf.readLine(); } catch(NumberFormatException e1) { System.out.println("INVALID ENTRY"); } try { s3=buf.readLine(); } catch(NumberFormatException e1) { System.out.println("INVALID ENTRY"); } if(s.equalsIgnoreCase(n[0])) { System.out.println("\n\n"); System.out.println("FOR BURGER"); System.out.println("THE PRICE IS RS.80");
System.out.println("ENTER HOW MANY BURGERS DO YOU WANT TO BUY:"); try { quan=Integer.parseInt(buf.readLine()); } catch(IOException e2) { System.out.println("INVALID ENTRY"); } bill=bill+(quan*50); } if(s1.equalsIgnoreCase(n[1])) { System.out.println("\n\n"); System.out.println("FOR NACHOS");
System.out.println("THE PRICE IS RS.100");
System.out.println("ENTER HOW MANY NACHOS DO YOU WANT TO BUY:"); try { quan=Integer.parseInt(buf.readLine()); } catch(IOException e2) { System.out.println("INVALID ENTRY"); } bill=bill+(quan*100); } if(s2.equalsIgnoreCase(n[2])) { System.out.println("\n\n"); System.out.println("FOR COKE"); System.out.println("THE PRICE IS RS.70");
System.out.println("ENTER HOW MANY COKE DO YOU WANT TO BUY:"); try { quan=Integer.parseInt(buf.readLine()); } catch(IOException e2) { System.out.println("INVALID ENTRY"); } bill=bill+(quan*70); } if(s3.equalsIgnoreCase(n[3])) { System.out.println("\n\n"); System.out.println("FOR POPCORN"); System.out.println("THE PRIC IS RS.90");
System.out.println("ENTER HOW MANY POPCORN DO YOU WANT TO BUY:"); try { quan=Integer.parseInt(buf.readLine()); } catch(IOException e2) { System.out.println("INVALID ENTRY"); } bill=bill+(quan*90); } } }
