This document provides an overview of the Java programming language. It discusses key Java concepts like object-oriented programming, classes, methods, streams, and input/output. It also covers Java syntax like primitive types, variables, operators, flow control, and arrays. The document explains how Java code is compiled to bytecode and run on the Java Virtual Machine, making it platform independent.
Here I discuss about Java programming language and easiest way to solve programming problem. Java basic syntax and their uses are described briefly so that anyone can easily understand within very short time. If anyone follow the slide with proper way,I assure that he or she will find java programming interesting.
Here I discuss about Java programming language and easiest way to solve programming problem. Java basic syntax and their uses are described briefly so that anyone can easily understand within very short time. If anyone follow the slide with proper way,I assure that he or she will find java programming interesting.
Mahika Tutorials sharing PPT slide for core java programming language. Go threw this slide and visit our YouTube page too
https://www.youtube.com/c/mahikatutorials
Every value in Java has a data type. Java supports two kinds of data types: primitive data types and reference data types. Primitive data types represent atomic, indivisible values. Java has eight Numeric data types: byte, short, int,
An operator is a symbol that is used to perform some type of computation on its operands. Java contains a rich set of
operators. Operators are categorized as unary, binary, or ternary based on the number of operands they take. They are categorized as arithmetic, relational, logical, etc. based on the operation they perform on their operands.
long, float, double, char, and boolean. Literals of primitive data types are constants. Reference data types represent
references of objects in memory. Java is a statically typed programming language. That is, it checks the data types of all values at compile time.
Mahika Tutorials sharing PPT slide for core java programming language. Go threw this slide and visit our YouTube page too
https://www.youtube.com/c/mahikatutorials
Every value in Java has a data type. Java supports two kinds of data types: primitive data types and reference data types. Primitive data types represent atomic, indivisible values. Java has eight Numeric data types: byte, short, int,
An operator is a symbol that is used to perform some type of computation on its operands. Java contains a rich set of
operators. Operators are categorized as unary, binary, or ternary based on the number of operands they take. They are categorized as arithmetic, relational, logical, etc. based on the operation they perform on their operands.
long, float, double, char, and boolean. Literals of primitive data types are constants. Reference data types represent
references of objects in memory. Java is a statically typed programming language. That is, it checks the data types of all values at compile time.
This has been presented in association with Robosepians for Java concepts. Basic concepts of Java including features, conditional statements, loop statements, arrays, string, primitive datatypes, essentials of Java including oops concepts, classes, objects, polymorphism, advance topics including packages, exception handling, multihtreading and network programming have been discussed.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
1. Java Tutorial By Sanjeevini India -Slide Show
Write Once, Run Anywhere
2. Java - General
Java is:
– platform independent programming
language
– similar to C++ in syntax
– similar to Smalltalk in mental paradigm
Pros: also ubiquitous to net
Cons: interpreted, and still under
development (moving target)
3. Java - General
Java has some interesting features:
– automatic type checking,
– automatic garbage collection,
– simplifies pointers; no directly accessible
pointer to memory,
– simplified network access,
– multi-threading!
4. How it works…!
Compile-time Environment Compile-time Environment
Class
Loader Java
Class
Bytecode Libraries
Java Verifier
Source
(.java)
Just in
Java Java
Time
Bytecodes Interpreter Java
Compiler
move locally Virtual
or through machine
Java network
Compiler
Runtime System
Java Operating System
Bytecode
(.class )
Hardware
5. How it works…!
Java is independent only for one reason:
– Only depends on the Java Virtual Machine
(JVM),
– code is compiled to bytecode, which is
interpreted by the resident JVM,
– JIT (just in time) compilers attempt to
increase speed.
6. Java - Security
Pointer denial - reduces chances of
virulent programs corrupting host,
Applets even more restricted -
– May not
• run local executables,
• Read or write to local file system,
• Communicate with any server other than the
originating server.
7. Object-Oriented
Java supports OOD
– Polymorphism
– Inheritance
– Encapsulation
Java programs contain nothing but
definitions and instantiations of classes
– Everything is encapsulated in a class!
8. Java Advantages
Portable - Write Once, Run Anywhere
Security has been well thought through
Robust memory management
Designed for network programming
Multi-threaded (multiple simultaneous tasks)
Dynamic & extensible (loads of libraries)
– Classes stored in separate files
– Loaded only when needed
10. Primitive Types and Variables
boolean, char, byte, short, int, long, float, double etc.
These basic (or primitive) types are the only types
that are not objects (due to performance issues).
This means that you don’t use the new operator to
create a primitive variable.
Declaring primitive variables:
float initVal;
int retVal, index = 2;
double gamma = 1.2, brightness
boolean valueOk = false;
11. Initialisation
If no value is assigned prior to use, then the
compiler will give an error
Java sets primitive variables to zero or false
in the case of a boolean variable
All object references are initially set to null
An array of anything is an object
– Set to null on declaration
– Elements to zero false or null on creation
12. Declarations
int index = 1.2; // compiler error
boolean retOk = 1; // compiler error
double fiveFourths = 5 / 4; // no error!
float ratio = 5.8f; // correct
double fiveFourths = 5.0 / 4.0; // correct
1.2f is a float value accurate to 7 decimal places.
1.2 is a double value accurate to 15 decimal places.
13. Assignment
All Java assignments are right associative
int a = 1, b = 2, c = 5
a=b=c
System.out.print(
“a= “ + a + “b= “ + b + “c= “ + c)
What is the value of a, b & c
Done right to left: a = (b = c);
14. Basic Mathematical Operators
* / % + - are the mathematical operators
* / % have a higher precedence than + or -
double myVal = a + b % d – c * d / b;
Is the same as:
double myVal = (a + (b % d)) –
((c * d) / b);
15. Statements & Blocks
A simple statement is a command terminated by
a semi-colon:
name = “Fred”;
A block is a compound statement enclosed in
curly brackets:
{
name1 = “Fred”; name2 = “Bill”;
}
Blocks may contain other blocks
16. Flow of Control
Java executes one statement after the other
in the order they are written
Many Java statements are flow control
statements:
Alternation: if, if else, switch
Looping: for, while, do while
Escapes: break, continue, return
17. If – The Conditional Statement
The if statement evaluates an expression and if that
evaluation is true then the specified action is taken
if ( x < 10 ) x = 10;
If the value of x is less than 10, make x equal to 10
It could have been written:
if ( x < 10 )
x = 10;
Or, alternatively:
if ( x < 10 ) { x = 10; }
18. Relational Operators
== Equal (careful)
!= Not equal
>= Greater than or equal
<= Less than or equal
> Greater than
< Less than
19. If… else
The if … else statement evaluates an expression and
performs one action if that evaluation is true or a
different action if it is false.
if (x != oldx) {
System.out.print(“x was changed”);
}
else {
System.out.print(“x is unchanged”);
}
20. Nested if … else
if ( myVal > 100 ) {
if ( remainderOn == true) {
myVal = mVal % 100;
}
else {
myVal = myVal / 100.0;
}
}
else
{
System.out.print(“myVal is in range”);
}
21. else if
Useful for choosing between alternatives:
if ( n == 1 ) {
// execute code block #1
}
else if ( j == 2 ) {
// execute code block #2
}
else {
// if all previous tests have failed,
execute code block #3
}
22. A Warning…
WRONG! CORRECT!
if( i == j ) if( i == j ) {
if ( j == k )
if ( j == k )
System.out.print(
System.out.print(
“i equals k”);
“i equals k”);
}
else
else
System.out.print(
“i is not equal
System.out.print(“
to j”);
i is not equal to
j”); // Correct!
23. The switch Statement
switch ( n ) {
case 1:
// execute code block #1
break;
case 2:
// execute code block #2
break;
default:
// if all previous tests fail then
//execute code block #4
break;
}
24. The for loop
Loop n times
for ( i = 0; i < n; n++ ) {
// this code body will execute n times
// ifrom 0 to n-1
}
Nested for:
for ( j = 0; j < 10; j++ ) {
for ( i = 0; i < 20; i++ ){
// this code body will execute 200 times
}
}
25. while loops
while(response == 1) {
System.out.print( “ID =” +
userID[n]);
n++;
response = readInt( “Enter “);
}
What is the minimum number of times the loop
is executed?
What is the maximum number of times?
26. do {… } while loops
do {
System.out.print( “ID =” + userID[n] );
n++;
response = readInt( “Enter ” );
}while (response == 1);
What is the minimum number of times the loop
is executed?
What is the maximum number of times?
27. Break
A break statement causes an exit from the
innermost containing while, do, for or
switch statement.
for ( int i = 0; i < maxID, i++ ) {
if ( userID[i] == targetID ) {
index = i;
break;
}
} // program jumps here after break
28. Continue
Can only be used with while, do or for.
The continue statement causes the innermost loop to
start the next iteration immediately
for ( int i = 0; i < maxID; i++ ) {
if ( userID[i] != -1 ) continue;
System.out.print( “UserID ” + i + “ :” +
userID);
}
29. Arrays
Am array is a list of similar things
An array has a fixed:
– name
– type
– length
These must be declared when the array is created.
Arrays sizes cannot be changed during the execution
of the code
30. myArray = 3 6 3 1 6 3 4 1
0 1 2 3 4 5 6 7
myArray has room for 8 elements
the elements are accessed by their index
in Java, array indices start at 0
31. Declaring Arrays
int myArray[];
declares myArray to be an array of integers
myArray = new int[8];
sets up 8 integer-sized spaces in memory,
labelled myArray[0] to myArray[7]
int myArray[] = new int[8];
combines the two statements in one line
32. Assigning Values
refer to the array elements by index to store values in
them.
myArray[0] = 3;
myArray[1] = 6;
myArray[2] = 3; ...
can create and initialise in one step:
int myArray[] = {3, 6, 3, 1, 6, 3, 4, 1};
33. Iterating Through Arrays
for loops are useful when dealing with arrays:
for (int i = 0; i <
myArray.length; i++) {
myArray[i] = getsomevalue();
}
34. Arrays of Objects
So far we have looked at an array of primitive types.
– integers
– could also use doubles, floats, characters…
Often want to have an array of objects
– Students, Books, Loans ……
Need to follow 3 steps.
35. Declaring the Array
1. Declare the array
private Student studentList[];
– this declares studentList
2 .Create the array
studentList = new Student[10];
– this sets up 10 spaces in memory that can
hold references to Student objects
3. Create Student objects and add them to the
array: studentList[0] = new
Student("Cathy", "Computing");
37. Classes ARE Object Definitions
OOP - object oriented programming
code built from objects
Java these are called classes
Each class definition is coded in a
separate .java file
Name of the object must match the
class/object name
38. The three principles of OOP
Encapsulation
– Objects hide their
functions (methods) and
data (instance
variables)
Inheritance car Super class
– Each subclass inherits
all variables of its auto-
manual
superclass matic Subclasses
Polymorphism
– Interface same despite draw()
different data types draw()
39. Simple Class and Method
Class Fruit{
int grams;
int cals_per_gram;
int total_calories() {
return(grams*cals_per_gram);
}
}
40. Methods
A method is a named sequence of code that can be
invoked by other Java code.
A method takes some parameters, performs some
computations and then optionally returns a value (or
object).
Methods can be used as part of an expression
statement.
public float convertCelsius(float tempC) {
return( ((tempC * 9.0f) / 5.0f) + 32.0 );
}
41. Method Signatures
A method signature specifies:
– The name of the method.
– The type and name of each parameter.
– The type of the value (or object) returned by the method.
– The checked exceptions thrown by the method.
– Various method modifiers.
– modifiers type name ( parameter list ) [throws exceptions ]
public float convertCelsius (float tCelsius ) {}
public boolean setUserInfo ( int i, int j, String name ) throws
IndexOutOfBoundsException {}
42. Public/private
Methods/data may be declared public or
private meaning they may or may not be
accessed by code in other classes …
Good practice:
– keep data private
– keep most methods private
well-defined interface between classes -
helps to eliminate errors
43. Using objects
Here, code in one class creates an instance
of another class and does something with it
…
Fruit plum=new Fruit();
int cals;
cals = plum.total_calories();
Dot operator allows you to access (public)
data/methods inside Fruit class
44. Constructors
The line
plum = new Fruit();
invokes a constructor method with which you
can set the initial data of an object
You may choose several different type of
constructor with different argument lists
eg Fruit(), Fruit(a) ...
45. Overloading
Can have several versions of a method
in class with different types/numbers of
arguments
Fruit() {grams=50;}
Fruit(a,b) { grams=a; cals_per_gram=b;}
Bylooking at arguments Java decides
which version to use
46. Java Development Kit
javac - The Java Compiler
java - The Java Interpreter
jdb - The Java Debugger
appletviewer -Tool to run the applets
javap - to print the Java bytecodes
javaprof - Java profiler
javadoc - documentation generator
javah - creates C header files
48. Streams and I/O
basic classes for file IO
– FileInputStream, for reading from a file
– FileOutputStream, for writing to a file
Example:
Open a file "myfile.txt" for reading
FileInputStream fis = new FileInputStream("myfile.txt");
Open a file "outfile.txt" for writing
FileOutputStream fos = new FileOutputStream ("myfile.txt");
48
49. Display File Contents
import java.io.*;
public class FileToOut1 {
public static void main(String args[]) {
try {
FileInputStream infile = new FileInputStream("testfile.txt");
byte buffer[] = new byte[50];
int nBytesRead;
do {
nBytesRead = infile.read(buffer);
System.out.write(buffer, 0, nBytesRead);
} while (nBytesRead == buffer.length);
}
catch (FileNotFoundException e) {
System.err.println("File not found");
}
catch (IOException e) { System.err.println("Read failed"); }
}
} 49
50. Filters
•Once a stream (e.g., file) has been opened, we
can attach filters
•Filters make reading/writing more efficient
•Most popular filters:
• For basic types:
•DataInputStream, DataOutputStream
• For objects:
•ObjectInputStream, ObjectOutputStream
50
51. Writing data to a file using Filters
import java.io.*;
public class GenerateData {
public static void main(String args[]) {
try {
FileOutputStream fos = new FileOutputStream("stuff.dat");
DataOutputStream dos = new DataOutputStream(fos);
dos.writeInt(2);
dos.writeDouble(2.7182818284590451);
dos.writeDouble(3.1415926535);
dos.close(); fos.close();
}
catch (FileNotFoundException e) {
System.err.println("File not found");
}
catch (IOException e) {
System.err.println("Read or write failed");
}
} 51
}
52. Reading data from a file using filters
import java.io.*;
public class ReadData {
public static void main(String args[]) {
try {
FileInputStream fis = new FileInputStream("stuff.dat");
DataInputStream dis = new DataInputStream(fis);
int n = dis.readInt();
System.out.println(n);
for( int i = 0; i < n; i++ ) { System.out.println(dis.readDouble());
}
dis.close(); fis.close();
}
catch (FileNotFoundException e) {
System.err.println("File not found");
}
catch (IOException e) { System.err.println("Read or write failed");
}
} 52
}
53. Object serialization
Write objects to a file, instead of writing primitive
types.
Use the ObjectInputStream, ObjectOutputStream
classes, the same way that filters are used.
53
54. Write an object to a file
import java.io.*;
import java.util.*;
public class WriteDate {
public WriteDate () {
Date d = new Date();
try {
FileOutputStream f = new FileOutputStream("date.ser");
ObjectOutputStream s = new ObjectOutputStream (f);
s.writeObject (d);
s.close ();
}
catch (IOException e) { e.printStackTrace(); }
public static void main (String args[]) {
new WriteDate ();
}
} 54
55. Read an object from a file
import java.util.*;
public class ReadDate {
public ReadDate () {
Date d = null;
ObjectInputStream s = null;
try { FileInputStream f = new FileInputStream ("date.ser");
s = new ObjectInputStream (f);
} catch (IOException e) { e.printStackTrace(); }
try { d = (Date)s.readObject (); }
catch (ClassNotFoundException e) { e.printStackTrace(); }
catch (InvalidClassException e) { e.printStackTrace(); }
catch (StreamCorruptedException e) { e.printStackTrace(); }
catch (OptionalDataException e) { e.printStackTrace(); }
catch (IOException e) { e.printStackTrace(); }
System.out.println ("Date serialized at: "+ d);
}
public static void main (String args[]) { new ReadDate (); } 55
}