Java Syntax
Create a simple "Hello World" program
Syntax Explained
Java Comments
Single-line comment before a line of code Single-line comment at the end of a line of code Multi-line comment
Comments Explained
Java Variables
Create a string variable Create an integer variable Create a variable without assigning the value, and assign the value later Overwrite an existing variable value Create a final variable (unchangeable and read-only) Combine text and a variable on display Add a variable to another variable Declare many variables of the same type with a comma-separated list
Variables Explained
Java Data Types
A demonstration of different data types in Java Create a byte type Create a short type Create an int type Create a long type Create a float type Create a double type Create a boolean type Create a char type Create a String type
Data Types Explained
Java Type Casting
Widening Casting Narrowing Casting
Type Casting Explained
Java Operators
Addition operator Subtraction operator Multiplication operator Division operator Modulus operator Increment operator Decrement operator Assignment operator Comparison operator Logical operator
Operators Explained
Java Strings
Create a string Quotes inside a string Find the length of a string Using methods to convert strings to uppercase and lowercase Finding a string in a string String concatenation If you add a number and a string, the result will be a string concatenation
Strings Explained
Java Math
Math.max(x,y) - return the highest value of x and y Math.min(x,y) - return the lowest value of x and y Math.sqrt(x) - return the square root of x Math.abs(x) - return the absolute (positive) value of x Math.random() - return a random number between 0 and 1
Math Explained
Java Booleans
Create a boolean type Find out if an expression is true or false Use the "equal to" operator to evaluate a boolean expression
Booleans Explained
Java If...Else (Conditions)
The if statement The else statement The else if statement
If...Else Explained
Java Switch
The switch statement The switch statement with a default keyword
Switch Explained
Java Loops
While loop Do while loop For loop For-each loop Break a loop Continue a loop
Loops Explained
Java Arrays
Create and access an array Change an array element Find the length of an array Access an array Loop through an array Loop through an array with for-each Multidimensional array Loop through a multidimensional array
Arrays Explained
Java Methods
Create and call a method Call a method multiple times Method with parameters Method with multiple parameters Return value A method with if...else Method overloading Recursion Recursive function with a halting condition
Methods Explained
Java Classes and Objects
Create a class and an object of a class Create multiple objects of a class Accessing class attributes (variables) Modify attributes Override existing attribute values Multiple attributes Create a class method Method with parameters Access class methods with an object Create a class constructor Constructor with parameters
Classes and Objects Explained
Java Modifiers
Public class Default class Public attributes Private attributes Default attributes Protected attributes Final class Abstract class with abstract methods
Modifiers Explained
Java Encapsulation
Java encapsulation (getters and setters)
Encapsulation Explained
Java Packages
Import a class from the Java API Import a package from the Java API Create a package
Packages Explained
Java Inheritance
Java inheritance (extends) Java polymorphism
Inheritance Explained
Java Inner Classes
Inner class Private inner class (error when trying to access it from an outside class) Static inner class Access outer class from inner class
Inner Classes Explained
Java Abstraction & Interfaces
Java abstract classes and methods Java interface (implements) Multiple interfaces
Interfaces Explained
Java Enums
Create an enum with a group of constants An enum inside a class An enum in a switch statement Loop through an enum
Enums Explained
Java User Input
Read user input Read user input of various types
User Input Explained
Java Dates
Display current date Display current time Display current date and time Formatting date and time
Dates Explained
Java ArrayList
Create an ArrayList Access an item in an ArrayList Remove an item from an ArrayList Remove all items from an ArrayList Get the size of an ArrayList Loop through an ArrayList Loop through an ArrayList with for-each Create an ArrayList that should store numbers (integers)
ArrayList Explained
Java HashMap
Create a HashMap Access an item in a HashMap Remove an item from a HashMap Remove all items from a HashMap Get the size of a HashMap Loop through a HashMap Create a HashMap that should store String keys and Integer values
HashMap Explained
Java HashSet
Create a HashSet and add items to it Check if an item exists in a HashSet Remove an item from a HashSet Remove all items from a HashSet Get the size of a HashSet Loop through a HashSet Create a HashSet that should store Integer values
HashSet Explained
Java Iterator
Getting an iterator Looping throug a collection Removing items from a collection
Iterator Explained
Java Wrapper Classes
Create an ArrayList that should store numbers (integers) Create wrapper objects Using wrapper methods Convert wrapper objects to strings
Wrapper Classes Explained
Java Exceptions (Try...Catch)
The try...catch statement The finally statement The throw statement
Exceptions Explained
Java Regular Expressions
Search for the word "example" in a sentence
Regular Expressions Explained
Java Threads
Running a thread by extending the thread class Running a thread by implementing the Runnable interface Concurrency problems Avoid concurrency problems
Threads Explained
Java Files
Create a file Write to a file Read a file Get file information Delete a file
Files Explained