Basics of Java.ppsx

class A{
public static void main(String args[]){
main method
System.out.println(“My Program”);
The command given to print. A type of a
method
}
}
Key word
Creation of Sajitha Tharaka-
sajithatharaka@gmail.com

package abc;
import java.util.ArrayList;
public class A{
}
class B{
}
class C{
}
Class declaration
More than one non public
Only one Can have many
A.java
If public must
match
Remember Order
PIC

m( ) {
return []; //return statement
}
Return type
Modifiers
Parameter list
m=method name
There can’t be methods
inside methods

First Symbol
Character
$
_
Number
Any combination
No key words
No limit
No spaces
Case sensitive

class A{
}
}
machines=methods
factory = class

class A{
}
class B{
}
class C{
}
}
D.java
Javac D.java
Java C

int i;
Declaration
i =5; Assignment
int i=5; Declaration and Assignment
Or called Field
int i=5;
Data type
Variable name
Value

Primitive Object
byte
short
int
long
float
double
char
boolean
Classes which
extends the object
class
integers
Floating point
characters
boolean

10 10
byte i=10; int i=10;
Differs from memory allocation in the RAM

float f=3.14;
Double d=3.14;
float f=(float)3.14;
float f=3.14f; // F or f
double d=3.14d; // D or d

Char c=‘a’;
Char c=o – 65535 ;
Char c=‘b’, ‘f’, ‘n’, ‘r’, ‘t’, ‘’’, ‘”’;
Char c=‘u0000’ – ‘uffff’; // unicode values
Char c= -98; // compile error
Char c=(char)-98;
Char c=0x0000 – 0xffff; // hexa values

boolean b=true;
boolean b=true;
boolean b=1;
boolean b=0;

m( ) {
return []; //return statement
}
}
class A{
Like an arm in a
machine
What should be
out put. Data
types are used

There ‘s no return
statement.
Nothing is out put.
Like armless Machine.
static void flag(byte a){
System.out.println("A");
}
static void name(int x){
System.out.println("B");
}
static void age(short y){
System.out.println("C");
}

Basics of Java.ppsx

Recommended

Recommended

More Related Content

More from Sajitha Pathirana

More from Sajitha Pathirana (11)

Recently uploaded

Recently uploaded (20)

Basics of Java.ppsx