OOP tALAGA

Java Netbeans IDE Function

Prepares the environment for developing java applications

IDE Full form

Integrated Development Environment

Java Netbeans

Platform to write Java code and applications (Version 7 ngayon)

What does java develop?

Desktop applications, client-server applications, mobile phone applications, games

Java major advantage

Platform independent

Java’s own runtime environment

Java Virtual Machine (JVM)

Current owner of java

Sun Microsystems

What to download?

Java Virtual Machine (JVM) and Java Development Kit (JDK)

Java code to write & extension

Source code wiith .java extension

What compiled the source code?

Another program called Javac that turns it into a Java byte code with .class extension (there should be no present errors)

File that Java Virtual Machine runs

Class file

Java Comments

Grayed out areas with forward slashes (// for single line comments; /* */ for multiline comments and asterisks that the compiler ignores

Javadoc comments

Starts with /** ends with */ to document the code (converted to HTML)

Java is case sensitive

True

Java code instructions end with a

Semicolon (;)

public class MyFirstProgram { }

Class segment notes the starting and ending of a java class segment code

Public static void main(String[] args){ }

Method

Public in “public static void main(String[] args){

the code can be accessed outside the class without creating new objects

Void in “public static void main(String[] args){

This part of the code does not return any value

Main in “public static void main(String[] args){

Denotes starting point of the java program

IntelliSense

NetBeans tries to display a list of available options after “.”

.Jar file (java archive) function

Cleans and builds your project with all necessary files for export if the program needs to be shared; will be put in a dist folder

Data

can be text, numbers, pointers, objects or some specified memory location

How is data accessed

Concatenation

Joining together direct text and a variable

You cannot start with a number for a variable name

True

You cannot have the same variable name with a keyword

True

Variable names can have a space

False

Variable names are not case sensitive

False

Java minimum and maximum value for numbers

+-2147483647 (use double to get a bigger/smaller number)

Operator Precedence

Order in which arithmetic’s operations are executed

Priority in operators

Multiplication & Division > addition and subtraction

Double quotes

String variable

Single quotes

char variable

Import java.util.Scanner; function

Tells java you want to use the scanner class in the util package of java library

Scanner in Import java.util.Scanner;

Class that handles inputs

Util in Import java.util.Scanner;

utility package of the java library where scanner is stored

Scanner variable

Scanner user_input = new Scanner (System.in);

New in Scanner user_input = new Scanner (System.in);

Creates the new objects

System.in in Scanner user_input = new Scanner (System.in);

Specifies for system input

User_input in Scanner user_input = new Scanner (System.in);

TThe variable that is called to call the input methods

Next method in Scanner user_input = new Scanner (System.in);

Gets the next string of text or int of number that a user types

Println

Cursor moves to a new line after the output

Print

Cursor stays on the same line

If statement format

if(Condition {//codes to be executed if true}

Comparison Operators

> Greater than, < Less than, >= greater or equal to,

Logical Operators

&& AND, || OR, == HAS A VALUE OF, ! NOT

If else statement structure

if(condition){code to be executed} else {code to be executed}

Nested IF statement

IF statement inside another IF statement

Boolean values

One with two choices: True or false, yes or no, 1 or 0

Switch statement definition

Selection statement; value of the expression is

compared with the values of each case; selecting one of many code blocks to be executed

Switch statement structure

switch(your test variable) { case Testing value: statement to be executed; break; default: statement to output if no matching case found; }

Looping/iteration

Repeat execution of statements a number of times; the same statement is being repeated many time over and at some point has to stop

For loop structure

for(initial value; condition; increment/decrement { statements to be repeated if true }

Intial value in for loops

Sets at what number should the repeat process start

Condition in for loops

Repeat should occur only when this condition is true

Increment/decrement

Move the counter forward or backward

Do while loop

do { Statements to execute } while (condition to check); // execution occur before checking of the condition

While loop

executes statements if the condition is true; while(condition) {}

Array definition

list store of values of the same type with specifying type eof data

Index starts at value…

0

Array structure

int[] myNums; [nextline ito] new int[5] to also indicate the size (all index are 0 unless stated)

Multidimensional arrays

arrays of multiple rows and columns (table) // 2 indices // int [][] myNums = new int[5][4]

.length

property of an array that returns the actual length of the array

Object-oriented programming

deals about creating objects that contain both data and functions

Oak

Java’s previous name

1995 by Oracle

Java created

Java requires:

main function that accepts an array of arguments enclosed in a class

Char description and size

nonprintable characters 16bits

Boolean description and size

True or false1 bit

Int description and size

whole numbers 32 bits

Short description and size

smaller than int 16 bits

Byte description and size

network packets 8 bits

Long description and size

larger than int 64 bits

Float description and size

numbers with floating points 32 bits

Double description and size

larger numbers with floating points

Format for declaring variables

Expression/statement function

changes the value of the variable being used in the condition

Continue in loops

the continue statement skips and moves to the end of the iteration

For-each traversal definition

for-each loop cycles through an object collection where type specifies array type and itvar is the iterator variable (accepts elements from beginning to end on eat a time)

For-each traversal format

for(type itvar:collection) statement block

Xvals in for(int xvals []:nums)

one-dimensional array of integers

Arraycopy

method available in the system class that can be used to copy data from one array to another