Std 12 Computer Chapter 7 Java Basics (Part 1) by Nuzhat Memon Introduction to Java Java Development Kit (JDK) Java Runtime Environment (JRE) java is a platform independent Bytecode in java java interpreter Structure of a java program literals in java 3 kinds of comments in java (single line comment, multiline comment, documentation comment) Expression in java Operator in java Looping in java continue and break statement in java gseb computer paper solution 2020 english medium

1. Chapter 7
Java Basics
(Part 1)
Presented by nuzhat memon

2. Presented by Nuzhat Memon
Introduction to Java
 Java is an object-oriented programming language
developed at Sun Microsystems, a company a best
known for its high-end Unix workstations, in 1991.
 Modeled after c++, the java language was designed to
be small, simple, fast, efficient and portable across
platform and operating systems.
 Java is considered as one of the ideal language for
distributing executable programs via the WWW and also
general purpose programming language for developing
programs that are easily usable and portable across
different platforms.
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1991
Small
Efficient
fast
Portable
Simple
Bytecode
(Class file)
Windows
JVM
Linux
JVM
MAc
JVM

3. Presented by Nuzhat Memon
Introduction to Java (continue) | JDK
 JDK is used to develop and run Java program
 Java includes a set of class libraries that provide basic data types, system
input and output capabilities, and other utility functions.
 These Basic classes are part of the Java Development Kit (JDK).
 JDK has classes to support networking, common internet protocols and user
interface toolkit functions.
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Class libraries
Basic data types,
System input & output capabilities
and other utility functions
Development
tools
JDK (Java Development Kit)
Compiler

4. Presented by Nuzhat Memon
Java is Platform Indedpendent
 Platform independence is a program’s capability of being moved easily from one
computer system to another.
 Java is platform independent at both the source and the binary level..
 At the source level, java’s primitive data types have consistent sizes across all
development platforms.
 At binary level, platform independence is possible due to bytecode interpreter.
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Bytecode
(Class file)
Windows
JVM
Linux
JVM
MAc
JVM

5. Presented by Nuzhat Memon 5
LINUX JVM
Windows JVM
Java Platform Independent
Java
source code
(*.java)
Java
compiler
(javac)
Java
bytecode
(*.class)
JVM - Java
Interpreter
(java)
HelloWorld.java After compilation HelloWorld.class
(class file is our
bytecode)
JVM understand
only bytecode
MAC JVM

6. Presented by Nuzhat Memon
JVM (Java Virtual Machine) | Bytecode
 Program written in java are compiled into machine language for a computer that
doesn’t really exist. This is so-called “virtual” computer is known as the Java Virtual
Machine (JVM).
 The machine language for the java virtual machine is called java bytecode.
 Different java bytecode interpreter is needed for each type of computer.
 Advantage - Platform independent - Java binary files are actually in a form
called bytecodes that is not specific to any one processor or any operating
system.
 The only disadvantage of using bytecodes is its slow execution speed.
 There are tools available to convert java bytecodes into native code. Native code is
faster to execute, but then it does not remain machine independent.
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Compiler
Faster Execution Speed
Platform Dependent
Interpreter
Slow Execution Speed
Platform Independent
JVM Java Bytecode

7. Presented by Nuzhat Memon
Which of the following is missing from compilation process to
execute java application ?
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JVM - Java Interpreter(Java)
Java Compiler (Javac)
Java Source File (usually have
extension.java)
When we create a Java Program File, we usually save it as
filename.java which is called source code
And then we will Compile our source code using the
java compiler javac
Compiler will translate the whole program into machine
language known as bytecode in java and creates a file
with extension .class
Java Interpreter or JVM will read the bytecode line by
line and Run the class file on different OS or hardware
Java Bytecode file (*.class)
When java program created java source file using text
editor, which file extension should be given? .java
When the program gets compiled without error, compiler
creates a file with which extension ?.class
By using which extension file java interpreter bytecode
executes? java
Which of the following way user can run “abc.java”
source program through the application using java
interpreter? Java abc
To compile the java program we have to type what in
front of source filename? javac filename.java

8. Presented by Nuzhat Memon
Create Java application using SciTE editor
 Start SciTE application.
 Select File  New and type the java program.
 To save the file, select File Save with filename.java
 Compile source program using Tools Compile (Ctrl+F7)
 If the program is compiled without any error, execute it using
Tools  Go (F5)
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9. Presented by Nuzhat Memon
Structure Of A Java Program
+ In Java program, text in angle bracket < and > is used as a place holder.
+ Java consists of function header and the sequence of statements enclosed
between braces { and }
public class <class-name>
{
<optional – variable – declarations – and –methods>
public static void main(String [ ] args)
{
<statements>
}
<optional – variable – declarations – and – methods>
}
Java source file & class name must be same
System.out.print() and System.out.println() both methods are used to display results
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10. Presented by Nuzhat Memon
Overview
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byte age = 10
short number = 20
int count = 30
long area = 1234567
float pi = 3.14
double rate = 100.75
char ch = ‘n’
boolean Check = true
Data Type Variable Literal
Expression
A + B * C
//Comments

11. Presented by Nuzhat Memon
Data Types
+ Java supports 8 primitive data types.
+ Data Types – byte (1 byte), short (2 bytes), int (4 bytes), long (8 bytes),
float (4 bytes), double (8 bytes), char (2 bytes), Boolean (1 byte)
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byte, short, int, long Integer Store integer value
float, double Float Store floating point value
Char Character Single Unicode character
boolean Boolean Store true/false logical value

12. Presented by Nuzhat Memon 12
Data type
numbers character
2 bytes
char c=‘A’
integers
Eg 17,-38488,0
byte
1 byte
short
2 bytes
int
4 bytes
long
8 bytes
long num=4l
real numbers
Eg 5.8 ,-129.35, 3.14
Real numbers in Java are
compliant with IEEE 754
float
4 bytes
float Pi=3.14f
double
8 bytes
double var=0.1234567
boolean
1 byte
boolean b=true
I
n
t
e
g
e
r
byte 1 -128 to 127
short
2
-32768 to
32767
int
4
-2147483648
to 2147483647
long
8
-263 to 263-1
R
e
a
l
float
4
Upto 7
significant
digits
double
8
Upto 15
significant
digits
char 2
16 bit unicode
character
boolean 1
True , false
Default value
is false
(default data type of
floating point literal)
Signed values : -2 b-1-1 to 2 b-1 -2 b-1 to 2 b-1-1
Unsigned values: 0 to 2 b-1 0 to 2 b-1 -1
byte :
-2 8-1 to 2 8-1-1
-2 7 to 2 7-1
-128 to 127
short :
-2 16-1 to 2 16-1-1
-2 15 to 2 15-1
-32768 to 32767
int :
-2 32-1 to 2 32-1-1
-2 31to 2 31-1
-2147483648 to
2147483647
long:
-2 64-1 to 2 64-1-1
-2 63 to 2 63-1
-9223372036854775808
to 9223372036854775807
char :
0 to 2 16-1-1
0 to 215-1
0 to 65535
boolean:
True, false

13. Presented by Nuzhat Memon
Variable
+ A name used to refer to the data stored in memory is called a variable
+ Syntax <datatype-name> {variable-names};
+ Example int marks; | float rate; | char grade;
RULES TO DEFINE VARIABLE NAME
• It must begin with an alphabet, underscore (_) or dollar sign ($).
• No spaces are allowed in variables : birth date, my school project
• It cannot be a reserved word : class, public, static,void if etc
• Legal variable names : birth_date, result, CallCost, top5students, date, $price
• Illegal variable names : 4me, %discount, birth date
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14. Presented by Nuzhat Memon
Guidelines For Naming Variables
+ Choose meaningful variable names. (calculateArea, calculateCallCost)
+ Java allows variable name of any length.
+ Separate words with underscore. Ex : birth_date
+ Java is case-sensitive. So upper case and lower case are considered to
be different. Example variable X is different from the variable x and
a nuzhat is not a Nuzhat or NUZHAT.
+ Names of classes to begin with upper case.
+ Names of variables and of methods begin with lower case. Referred to
as camel case. Ex : birthDate, callCost
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15. Presented by Nuzhat Memon
Variable Types
There are 3 kinds of variables :
1) Instance variables
2) Class/Static variables
3) Local variables
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class Demo{
public static void main(String args[]){
int age=15;
float pi=3.14;
static int count=0;
void display(){
int total=50;
System.out.println(“Hello”);
}
}
}
Instance variables
local variable
Class variable

16. Presented by Nuzhat Memon
Literals- A name used for a constant value is known as literal. Different
kinds of literals in java for number, character, string and boolean values.
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Numeric Literals Boolean Literals
True and False
default value is False
Character Literals
16-bit Unicode characters
enclosed in ‘ ‘
Example ‘a’, ‘#’, ‘3’
String Literals
sequence of characters
enclosed in “”
Example “hello”,
Literals
Integer literals
Whole numbers
Real number literal
Floating point literals
standard
12.37
scientific
0.1237 x 102
0.1237e2
Escape character :
n : New Line
t : Tab
f : Form Feed
b : Backspace
r : Carriage return
decimal
Base 10
(0 to 9)
75,75L,-75
octal
Base 8
(0 to 7)
075
hexadecimal
Base 16
(0 to 9, A to F)
0x45 or 0X45
Unicode
integer
literals
u000
ufff
Binary
number
Digits 0 or 1
0b or 0B

17. Presented by Nuzhat Memon
Comments
Comments in a program are for human readers only
Comments are entirely ignored by the computer. They are not compiled or interpreted
in java
Java supports 3 types of comments :
1) Single line comment //
All the text up to the end of the line is ignored.
2) Multi line comment /* ..... */
Comments cannot be nested (comment inside a comment)
3) Documentation comment /** ..... */
(creating API documentation from the code, javadoc system)
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18. Presented by Nuzhat Memon
Expression
+ The basic building blocks of expressions are literals, variables and function calls.
+ More complex expressions can be built up by using operators to combine simpler
expression.
+ Operators include arithmetic operators (+, -, *, /, %), comparison operators (>, <, =,
…), logical operators (and, or, not…)
A + B * C (A + B) * C
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19. Presented by Nuzhat Memon
calculate simple and compound interest
class CalculateInterest
{
public static void main(String args[])
{
double p=10000;
double r=4.5;
double n=10;
double si,ci;
si = (p*r*n)/100;
ci= si + p;
System.out.println(“Simple interest is “ + si);
System.out.println(“Compound interest is “ + ci);
}
}
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1)Save the file as CalculateInterest.java on desktop
2) Open command prompt and type
cd desktop
javac CalculateInterest.java
java CalculateInterest

20. Presented by Nuzhat Memon
Operators
+ Operators are special symbols used to build an expression.
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Operators
1.
Arithmetic
Operators
2.
Comparison
operators
3. Logical
Operators
4,
Conditional
operators
5,
Assignment
operator

21. Presented by Nuzhat Memon 21
Basic arithmetic
operators are +, – ,
* , / , % (Modulus)
All these operators are
binary, they take 2
operands.
Used for byte, short,
int, long, float, double
Arithmetic Operators
Operator Meaning Eg
+ Addition 2+8
– Subtraction 2-8
* Multiplication 2*8
/ Division 8/2
% Reminder 8%3
++ is increment
operator, which
adds 1.
-- is decrement
operator, which
subtracts 1.
Increment/Decrement
Operators
++x
pre-increment
x++
post-increment
--x
pre-decrement
x-- post-decrement
Comparison
operators are
known as
relational
operators.
Comparison Operators
Operator Meaning
> Greater than
< Less than
>= Greater than or equal to
<= Less than or equal to
== Equal to
!= Not equal to
Logical operators
known as boolean
operators.
Logical operators :
AND, OR, XOR
(Exclusive OR),
NOT
Operator Sign Use
AND && Used to combine two
values – AND
OR || Used to combine two
values – OR
XOR ^ It returns true only if
operands are different
NOT ! Operant is true, result
is false & vice versa
Also known as ternary
operator.
Conditional operator
uses 3 operands.
It uses two symbols ?
and : in the expression.
Syntax : (boolean-expr)
? (expr1) : (expr2)
To assign a value
to variable by
using the
assignment
operator ‘=’
Syntax:
<variable> =
<expression>;
Conditional
Operator
Operators
Arithmetic
Operator
Increment and
Decrement
Operator
Comparison
Operator
Logical
Operator
Assignment
Operator

22. Presented by Nuzhat Memon
Looping
Java supports 3 types of looping constructs:
(1) for loop
+ Entry controlled or pre-test loop constructs.
+ for loop are executed if condition is true.
+ It is used when numbers of iterations are pre-defined.
(2) while loop
+ Entry controlled or pre-test loop constructs.
+ Loop are executed if condition is true.
+ It is used when number of iterations are not pre-determined.
(3) do...while loop
+ Exit controlled or post-test loop constructs.
+ It repeats the loop if the test condition is true.
+ Here, statements of loop are executed at least once.
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23. Presented by Nuzhat Memon
Statement
(1) IF STATEMENT
+ Used in a program to take one of two alternative coursed of action,
depending upon Boolean valued expression.
(2) SWITCH STATEMENT
+ Used when there are many alternative actions to be taken depending
upon the value of a variable or expression.
+ Test expression should be of the type byte, char, short or int or enum
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24. Presented by Nuzhat Memon
Statement
BREAK STATEMENT
+ Used to transfer the control outside switch/loop structure.
+ It is used to exit the loop.
+ It is jumps outside the nearest loop containing this statement.
CONTINUE STATEMENT
+ It is used to skip the following statement in a loop and continue
with the next iteration.
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25. Presented by Nuzhat Memon
Thanks!
Any questions?
You can find me at:
+ nuzhatmemon.com
+ Nuzhat.memon@gmail.com
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