Learn To Code: Introduction to java

Learn To Code: Intro to Java
Jahnavi Bollineni
Core Team Member
T R Sai Rakshith
Technical Team Member
P Sadhana
GDSC Lead

Introduction to Java
●Statically typed language
●Platform Independent
●Object-oriented programming language.
●Dynamic flexibility

●Mobile applications (specially Android
apps)
●Desktop applications
●Web applications
●Web servers and application servers
●Games
●Database connection
Applications of Java

● Java source code program(.java extension).
● JAVA Compiler to compile the source code
● Java bytecode program(.class extension)
● pass the java bytecode through an
interpreter called JVM (JAVA Virtual Machine)
● JVM converts and execute the code.
Working

●Every line of code that runs in Java
must be inside a class
●public - Access Modifier
●static - keyword
●void - keyword
method doesn’t return anything
● main - function
● String[ ] args - Java command line
arguments
Output in Java
public class Main
{
public static void main ( String[ ] args )
{
System.out.println("Hello
World");
}
}

Input in Java ● import java.util.Scanner;
● Scanner in = new
Scanner(System.in);
import java.util.Scanner;
public class Main
{
public static void main (String[ ] args)
{
Scanner input = new
Scanner(System.in);
String name = input.next();
System.out.println("Hello " + name);
}
}

Datatypes
Data types specify the different sizes and values that can be stored in the variable. There
are two types of data types in Java:
1.Primitive data types: The primitive data types include boolean, char, byte, short, int,
long, float and double.
2.Non-primitive data types: The non-primitive data types include Classes, Interfaces, and
Arrays.
What are Datatypes?

Learn To Code: Introduction to java

Operators in Java
There are many types of operators in Java which are given below:
● Unary Operator: expr++, expr--, ++expr, --expr, +expr, -expr
● Arithmetic Operator: *, /, %, +, -
● Relational Operator: <, >, <=, >=, ==, !=
● Bitwise Operator: &, |, ^
● Logical Operator: &&, ||
● Ternary Operator: ? :
● Assignment Operator: =, +=, -=, *=, /=, %=
Operator in Java is a symbol that is used to perform operations

● A variable is a name of the memory location.
● It is used to store data.
● Its value can be changed
● It is a way to represent memory location through symbol so that it can
be easily identified.
Let's see the syntax to declare a variable:
type variablename;
Variables
A little into variables!

Types of Variables in Java
●Local variable - A variable declared inside the body of the method is called local variable.
●Instance variable - A variable declared inside the class but outside the body of the
method, is called an instance variable.
●Static variable - A variable that is declared as static is called a static variable.

if, if-else and if-else-if ladder
Selection
Simple if statement:
if(condition)
{
statement 1;
}
if-else statement:
if(condition)
{
statement 1;
}
else
{
statement 2;
}
if-else-if ladder:
if(condition 1) {
statement 1;
}
else if(condition 2) {
statement 2;
}
else {
statement 2;
}
Syntax:

for loop
Iterations
Syntax:
for(initialization; condition; increment/decrement)
{
//block of statements
}

while loop
Iterations
Syntax:
while(condition){
//looping
statements
}

do - while loop
Iterations
do
{
//statements
} while (condition);
Syntax:

Switch Case
The Java switch statement executes one statement from multiple conditions.
1.It is like if-else-if ladder statement.
2.Switch cases works with byte, short, int, long, enum types and wrapper styles.
3.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.
What are Switch cases?

Switch Case
1.The switch expression is evaluated once.
2.The value of the expression is compared with the values of each case.
3.If there is a match, the associated block of code is executed.
4.The break and default keywords are optional.
How do they work?

Switch Case
switch(expression) {
case x:
// code block
break;
case y:
// code block
break;
default:
// code block
}
Syntax:

Methods in Java
● To call a method in Java, write the method's name followed by two parentheses () and a
semicolon.
● A method is a collection of statements that perform some specific task and return the
result to the caller.
● Methods allow us to reuse the code without retyping the code.

Components of a method
● Modifier
● The return type
● Method name
● Parameter list
● Exception list
● Method Body

Learn To Code: Introduction to java

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