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+---
+
+language: java
+
+author: Jake Prather
+
+author_url: http://github.com/JakeHP
+
+filename: learnjava.java
+
+---
+
+Java is a general-purpose, concurrent, class-based, object-oriented computer programming language.
+[Read more here.](http://docs.oracle.com/javase/tutorial/java/index.html)
+
+```java
+// Single-line comments start with //
+/*
+Multi-line comments look like this.
+*/
+
+// Import Packages
+import java.util.ArrayList;
+// Import all "sub-packages"
+import java.lang.Math.*;
+
+// Inside of the learnjava class, is your program's
+// starting point. The main method.
+public class learnjava
+{
+ //main method
+ public static void main (String[] args)
+ {
+
+System.out.println("->Printing");
+// Printing, and forcing a new line on next print, use println()
+System.out.println("Hello World!");
+System.out.println("Integer: "+10+" Double: "+3.14+ " Boolean: "+true);
+// Printing, without forcing a new line on next print, use print()
+System.out.print("Hello World - ");
+System.out.print("Integer: "+10+" Double: "+3.14+ " Boolean: "+true);
+
+///////////////////////////////////////
+// Types
+///////////////////////////////////////
+System.out.println("\n\n->Types");
+// Byte - 8-bit signed two's complement integer
+// (-128 <= byte <= 127)
+byte fooByte = 100;
+
+// Short - 16-bit signed two's complement integer
+// (-32,768 <= short <= 32,767)
+short fooShort = 10000;
+
+// Integer - 32-bit signed two's complement integer
+// (-2,147,483,648 <= int <= 2,147,483,647)
+int fooInt = 1;
+
+// Long - 64-bit signed two's complement integer
+// (-9,223,372,036,854,775,808 <= long <= 9,223,372,036,854,775,807)
+long fooLong = 100000L;
+
+// (Java has no unsigned types)
+
+// Float - Single-precision 32-bit IEEE 754 Floating Point
+float fooFloat = 234.5f;
+
+// Double - Double-precision 64-bit IEEE 754 Floating Point
+double fooDouble = 123.4;
+
+// Boolean - True & False
+boolean fooBoolean = true;
+boolean barBoolean = false;
+
+// Char - A single 16-bit Unicode character
+char fooChar = 'A';
+
+// Make a variable a constant
+final int HOURS_I_WORK_PER_WEEK = 9001;
+
+// Strings
+String fooString = "My String Is Here!";
+// \n is an escaped character that starts a new line
+String barString = "Printing on a new line?\nNo Problem!";
+System.out.println(fooString);
+System.out.println(barString);
+
+// Arrays
+//The array size must be decided upon declaration
+//The format for declaring an array is follows:
+//<datatype> [] <var name> = new <datatype>[<array size>];
+int [] intArray = new int[10];
+String [] stringArray = new String[1];
+boolean [] booleanArray = new boolean[100];
+
+// Indexing an array - Accessing an element
+System.out.println("intArray @ 0: "+intArray[0]);
+
+// Arrays are mutable; it's just memory!
+intArray[1] = 1;
+System.out.println("intArray @ 1: "+intArray[1]); // => 1
+intArray[1] = 2;
+System.out.println("intArray @ 1: "+intArray[1]); // => 2
+
+// Others to check out
+// ArrayLists - Like arrays except more functionality is offered,
+// and the size is mutable
+// LinkedLists
+// Maps
+// HashMaps
+
+///////////////////////////////////////
+// Operators
+///////////////////////////////////////
+System.out.println("\n->Operators");
+
+int i1 = 1, i2 = 2; // Shorthand for multiple declarations
+
+// Arithmetic is straightforward
+System.out.println("1+2 = "+(i1 + i2)); // => 3
+System.out.println("1+2 = "+(i2 - i1)); // => 1
+System.out.println("1+2 = "+(i2 * i1)); // => 2
+System.out.println("1+2 = "+(i1 / i2)); // => 0 (0.5, but truncated towards 0)
+
+// Modulo
+System.out.println("11%3 = "+(11 % 3)); // => 2
+
+// Comparison operators
+System.out.println("3 == 2? "+(3 == 2)); // => 0 (false)
+System.out.println("3 != 2? "+(3 != 2)); // => 1 (true)
+System.out.println("3 > 2? "+(3 > 2)); // => 1
+System.out.println("3 < 2? "+(3 < 2)); // => 0
+System.out.println("2 <= 2? "+(2 <= 2)); // => 1
+System.out.println("2 >= 2? "+(2 >= 2)); // => 1
+
+// Bitwise operators!
+/*
+~ Unary bitwise complement
+<< Signed left shift
+>> Signed right shift
+>>> Unsigned right shift
+& Bitwise AND
+^ Bitwise exclusive OR
+| Bitwise inclusive OR
+*/
+
+// Incrementations
+int i=0;
+System.out.println("\n->Inc/Dec-rementation");
+System.out.println(i++); //i = 1. Post-Incrementation
+System.out.println(++i); //i = 2. Pre-Incrementation
+System.out.println(i--); //i = 1. Post-Decrementation
+System.out.println(--i); //i = 0. Pre-Decrementation
+
+///////////////////////////////////////
+// Control Structures
+///////////////////////////////////////
+System.out.println("\n->Control Structures");
+if (false){
+ System.out.println("I never run");
+}else if (false) {
+ System.out.println("I am also never run");
+} else {
+ System.out.println("I print");
+}
+
+// While loop
+int fooWhile = 0;
+while(fooWhile < 100)
+{
+ //System.out.println(fooWhile);
+ //Increment the counter
+ //Iterated 99 times, fooWhile 0->99
+ fooWhile++;
+}
+System.out.println("fooWhile Value: "+fooWhile);
+
+// Do While Loop
+int fooDoWhile = 0;
+do
+{
+ //System.out.println(fooDoWhile);
+ //Increment the counter
+ //Iterated 99 times, fooDoWhile 0->99
+ fooDoWhile++;
+}while(fooDoWhile < 100);
+System.out.println("fooDoWhile Value: "+fooDoWhile);
+
+// For Loop
+int fooFor;
+//for loop structure => for(<start_statement>;<conditional>;<step>)
+for(fooFor=0;fooFor<100;fooFor++){
+ //System.out.println(fooFor);
+ //Iterated 99 times, fooFor 0->99
+}
+System.out.println("fooFor Value: "+fooFor);
+
+// Switch Case
+int month = 8;
+String monthString;
+switch (month){
+ case 1: monthString = "January";
+ break;
+ case 2: monthString = "February";
+ break;
+ case 3: monthString = "March";
+ break;
+ case 4: monthString = "April";
+ break;
+ case 5: monthString = "May";
+ break;
+ case 6: monthString = "June";
+ break;
+ case 7: monthString = "July";
+ break;
+ case 8: monthString = "August";
+ break;
+ case 9: monthString = "September";
+ break;
+ case 10: monthString = "October";
+ break;
+ case 11: monthString = "November";
+ break;
+ case 12: monthString = "December";
+ break;
+ default: monthString = "Invalid month";
+ break;
+}
+System.out.println("Switch Case Result: "+monthString);
+
+///////////////////////////////////////
+// Converting Data Types And Typcasting
+///////////////////////////////////////
+
+// Converting data
+
+// Convert String To Integer
+Integer.parseInt("123");//returns an integer version of "123"
+
+// Convert Integer To String
+Integer.toString(123);//returns a string version of 123
+
+// For other conversions check out the following classes:
+// Double
+// Long
+// String
+
+// Typecsating
+// You can also cast java objects, there's a lot of details and
+// deals with some more intermediate concepts.
+// Feel free to check it out here: http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html
+
+
+///////////////////////////////////////
+// Classes And Functions
+///////////////////////////////////////
+
+ // Read about the class, and function syntax before
+ // reading this.
+ System.out.println("\n->Classes & Functions");
+ // Call bicycle's constructor
+ Bicycle trek = new Bicycle();
+ // Manipulate your object
+ trek.speedUp(3);
+ trek.setCadence(100);
+ System.out.println("trek info: "+trek.toString());
+
+ // Classes Syntax:
+ // <public/private/protected> class <class name>{
+ // //data fields, constructors, functions all inside
+ // }
+ // Function Syntax:
+ // <public/private/protected> <return type> <function name>(<args>)
+ // Here is a quick rundown on access level modifiers (public, private, etc.)
+ // http://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html
+
+// This bracket ends the main method
+}
+ // The static field is only required because this class
+ // is nested inside of the learnjava.java class.
+ public static class Bicycle {
+
+ // Bicycle's Fields/Variables
+ public int cadence;
+ public int gear;
+ public int speed;
+
+ // Constructors are a way of creating classes
+ // This is a default constructor
+ public Bicycle(){
+ gear = 1;
+ cadence = 50;
+ speed = 5;
+ }
+
+ // This is a specified constructor (it contains arguments)
+ public Bicycle(int startCadence, int startSpeed, int startGear) {
+ gear = startGear;
+ cadence = startCadence;
+ speed = startSpeed;
+ }
+
+ // the Bicycle class has
+ // four functions/methods
+ public void setCadence(int newValue) {
+ cadence = newValue;
+ }
+
+ public void setGear(int newValue) {
+ gear = newValue;
+ }
+
+ public void applyBrake(int decrement) {
+ speed -= decrement;
+ }
+
+ public void speedUp(int increment) {
+ speed += increment;
+ }
+
+ public String toString(){
+ return "gear: "+Integer.toString(gear)+
+ " cadence: "+Integer.toString(cadence)+
+ " speed: "+Integer.toString(speed);
+ }
+ // bracket to close nested Bicycle class
+ }
+// bracket to close learnjava.java
+}
+
+```
+
+## Further Reading
+
+Other Topics To Research:
+
+* [Inheritance](http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html)
+
+* [Polymorphism](http://docs.oracle.com/javase/tutorial/java/IandI/polymorphism.html)
+
+* [Abstraction](http://docs.oracle.com/javase/tutorial/java/IandI/abstract.html)
+
+* [Exceptions](http://docs.oracle.com/javase/tutorial/essential/exceptions/index.html)
+
+* [Interfaces](http://docs.oracle.com/javase/tutorial/java/IandI/createinterface.html)
+
+* [Generics](http://docs.oracle.com/javase/tutorial/java/generics/index.html)
+
+* The links provided are just to get an understanding of the topic, feel free to google and find specific examples