Java Tutorial For Beginners - Step By Step | Java Basics | Java Certification Training | Edureka

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01 IntroductionTo Java
02 JVM vs JRE vs JDK
03 Java Fundamentals
04 Objects & Classes
05 Methods & Access Modifiers
06 Flow Of Control
07 Arrays
Topics For Today’s Discussion

Introduction To Java
High Level Programming Language
Father of Java is James Gosling
Released by Sun Microsystems in 1996
Write Once Run Anywhere (WORA)
Originally called OAK
Free and Open Source Software

Features Of Java
PortableRobustEasy
Distributed Object Oriented
Platform
Independent
MultithreadedInterpretedSecure

✓ JVM is an abstract machine that doesn’t exist
physically
✓ Provides runtime environment to drive the Java Code
or applications
✓ It compiles the Java code into bytecode
✓ It is platform dependent
JVM vs JRE vs JDK
Java Virtual Machine
JVM

✓ JRE is the environment within which the JVM runs
✓ It contains a set of libraries + other files that JVM uses
at runtime
✓ Also called Java RTE
JRE
JVM vs JRE vs JDK
JVM
Java Runtime Environment

JDK
JRE
JVM vs JRE vs JDK
JVM
✓ JDK is a software development environment which is
used to develop Java applications and applets
✓ It contains Development Tools and JRE
Java Development Kit

Java Objects
An real-world entity that
has state and behaviour is
known as an object
01State
It is the data (value) of an
object
Behavior02 It is the functionality) of an
object
03 Identity
The object identity is typically implemented
via a unique ID that is used internally by the
JVM
CHARACTERISTICS

Java Classes
A class is a group of objects which have common properties
class <class_name>{
field;
method;
}

Java Classes
A class may contain
Fields
Methods
Constructors
Blocks
Nested Class & Interface
class <class_name>{
field;
method;
}

Java
Fundamentals
Variables
DataTypes
Operators

Variables
DataTypes
Operators
Variable refers to the name of reserved memory area
1 2 3
Instance
Variables
Static
Variables
Local
Variables
Java Fundamentals - Variables

Variables
DataTypes
Operators
DataTypes
Primitive Non-Primitive
Boolean Numeric
Character Integral
Integer FloatingPoint
boolean char byte short int long float double
StringArray
Java Fundamentals – Data Types

Variables
DataTypes
Operators
2 31 4 5 6 7
Arithmetic
Operators
Bitwise
Operators
Logical
Operators
Relational
Operators
Ternary
Operators
Assignment
Operators
8
+ - *
? %
^
& |
&&
|| < > <=
>=
== !=
? : = += -=
*= /= %=
&= ^= |=
<<= >>=
>>>=
++X --X
X++ X--
+X –X
! ~
<< >>
>>>
Shift
Operators
Unary
Operators
Java Fundamentals - Operators

Java Methods
A method is a set of code that is grouped together to perform a specific operation
Pre Defined or Standard Library Methods User Defined Methods
A method must be written inside a class
Each method has its own signature
Java provides two types of methods

Java User Defined Methods
Method Initialization
Method Invocation
To use a method, you need to perform two steps:

Java Methods
Method Invocation
modifier returnType nameOfMethod (Parameter List)
{
// method body
}
✓ A method can be parameterized or non-parameterized
✓ Method definition consists of a method header and a method body
✓ You can Overload Method i.e. Provide same name to more than
one method but their data type or parameter list must be different

Java Methods
Method Invocation
✓ To use a method it needs to be invoked or called
✓ A method can be called in two ways:
1. Call by Value
2. Call by Reference
✓ When a program invokes a method, the program
control gets transferred to the called method
methodName()
methodName(parameter1, parameter2...)

Access Modifiers
Access modifiers helps to restrict the scope of a class, constructor , variable , method or data member
Default Public Private Protected

Access Modifiers
Default Public Private Protected
Same class
Same Package subclass
Same Package non-
subclass
Different package
subclass
Different package non-
subclass
Yes Yes Yes Yes
Yes No Yes Yes
Yes No Yes Yes
No No Yes Yes
No No No Yes

My First Java Program
class Demo{
public static void main(String args[]){
System.out.println("Hello Edureka!!!");
}
}
public static void main(String args[])

public static void main String args[]

It is a keyword which identifies the class related thing
It is used to define the Return Type of the Method
It is the name of the method that is searched by JVM as a starting
point for an application with a particular signature only
It is the parameter to the main Method where the argument name could
be anything
It is the access modifier of the main method
public
static
void
main
String args[]
NOTE: main() in Java is the most important method as it is the entry point of any java program

For
While
DoWhile
Iterative
Statements

For
While
DoWhile
It is a control structure that allows us to repeat certain operations by incrementing and
evaluating a loop counter
Iterative Statements – For Loop
Statement
Initialization
Condition
Increment
/Decrement
False
True
START
END

For
While
DoWhile
Iterative Statements – For Loop
Syntax
for(initialization; condition; incr/dcr)
{
code block;
}
Statement
Initialization
Condition
Increment
/Decrement
False
True
START
END

For
While
DoWhile
Iterative Statements – While Loop
It is a control structure that allows us to specify that a certain statement is to be executed
repetitively until the loop condition is false
Statement
Condition
False
True
START
END

For
While
DoWhile
Iterative Statements – While Loop
Syntax
while (boolean condition)
{
loop statements...
}
Statement
Condition
False
True
START
END

For
While
DoWhile
Iterative Statements – Do While Loop
It is a control structure that allows code to be executed repeatedly based on a given Boolean
condition and tests the condition before executing the loop body
Statement
Condition
False
True
START
END

For
While
DoWhile
Iterative Statements – Do While Loop
Statement
Condition
False
True
START
END
Syntax
do{
//code to be executed
}
while(condition);

Conditional
Statements
If
If-Else
Switch

If
If-Else
Switch
Conditional Statements - If
It is the simplest selection statement in the Java language that checks the condition
and executes the loop if condition is true
If Nested If

If
If-Else
Switch
If is the most simple decision making statement that decides whether a certain
statement or block of statements will be executed or not
Body of If
True
False
START
END
Test
Expression
Statement
below If
If
Nested If

If
If-Else
Switch
Syntax
if(condition)
{
//Statements to execute
if condition is true
}
If
Nested If

If
If-Else
Switch
It is an if statement or an if-else statement within an if statement
If
Nested If
Body of If
True False
START
END
Test
Expression
Statement
below If
Body of
Nested If
Body of If
True
Nested
Test
Expression

If
If-Else
Switch
Syntax
if (condition1)
{
// Executes when condition1 is true
if (condition2)
{
// Executes when condition2 is true
}
}
If
Nested If

If
If-Else
Switch
Conditional Statements - If Else
It is an upgraded if statement that tests the condition and if the condition is false then ‘else’
statement is executed
If-Else
If-Else-If
Ladder

If
If-Else
Switch
It tests the condition and if the condition is false then ‘else’ statement is executed
If-Else
If-Else-If Ladder
True False
START
END
Test
Expression
Statement
below If
Body of ElseBody of If

If
If-Else
Switch
If-Else
If-Else-If Ladder
Syntax
if (condition)
{
//Executes this block if condition is
true
}
else
{
//Executes this block if condition
is false
}

If
If-Else
Switch
If-Else
If-Else-If Ladder
If-else-if ladder allows the user to use many if else statement within a loop and in case one
of the condition holds true the rest of the loops is bypassed
True
False
START
Statement
below If-else-if
Statement 1
Test
Expression
Test
Expression
Test
Expression
Statement 2
Statement 3
Body of Else
False
True
True

If
If-Else
Switch
If-Else
If-Else-If Ladder
Syntax
if (condition)
{
statement;
}
else if (condition)
{
statement;
}
.
.
else
statement;

If
If-Else
Switch
Conditional Statements - Switch
The switch statement provides an easy way to execute conditions to different parts of the code
True
START Switch
Condition
1
Condition
n
Default
Condition
2
Statement 1
break;
Statement 2
break;
Statement n
break;
Default
Statement
True
True
True
False
False
False
Statement just below
Switch Case

If
If-Else
Switch
Conditional Statements - Switch
Syntax
switch (expression)
{
case value1:
statement1;
break;
case value2:
statement2;
break;
.
.
case valueN:
statementN;
break;
default:
statementDefault;
}

Jump Statements
break
continue
return

break
continue
return
Jump Statements - break
The break construct is used to break out of the middle of loops
After a break, all the remaining statements in the loop are skipped and the execution
continues with the immediate next statement outside the loop
It is used in loops (while, for, do-while) and in a switch case

break
continue
return
Jump Statements - break
Syntax
if(condition)
{
break;
}
Remaining body
of loop
Statement below loopBreak?
Test
Expression
True
No
Yes

break
continue
return
Jump Statements – continue
Continue statement is used to skip execution of statements within a loop
It doesn’t terminate the loop but just skips some part of it to start the
next iteration

break
continue
return
Jump Statements – continue
Remaining body
of loop
Statement below
loop
Continue?
Test
Expression
True
No
Yes
Syntax
if(condition)
{
continue;
}

break
continue
return
Jump Statements – return
The return statement is used to end the execution of a specific method and then return a value
It sends the program control back to the method caller
The data type of the returned value should always be equal to the data type of the method's declared
return value
Syntax
if(condition)
{
return;
}

Java Arrays – 1 Dimensional
1D
2D
Array is an object which contains fixed number of elements of a similar data type under same name
arrayRefVar = new dataType[arraySize];
=myArray new int[5]
myArray[0] myArray[1] myArray[2] myArray[3] myArray[4]
=myArray[0] 10

1D
2D
=myArray new int[5]
=myArray[2]
10
30
=myArray[3] 40
=myArray[4] 50
=myArray[1] 20

1D
2D
=myArray new int[5]
10 30 40 5020

1D
2D
Like a 1D array, a 2D array is also a collection of data cells, all of the same type, which can be given a
single name
datatype[][] arrayRefVar = new dataType[row][col];
=int[][] myArray new int[2][2]
myArray[0][0] myArray[0][1]
=myArray[0][0] 100

1D
2D
single name
=myArray[0][1] 200
100
=myArray[1][0] 300
=myArray[1][1] 400

1D
2D
single name
200100
300 400

Java Tutorial For Beginners - Step By Step | Java Basics | Java Certification Training | Edureka

Java Tutorial For Beginners - Step By Step | Java Basics | Java Certification Training | Edureka

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