diff options
Diffstat (limited to 'java.html.markdown')
| -rw-r--r-- | java.html.markdown | 79 |
1 files changed, 65 insertions, 14 deletions
diff --git a/java.html.markdown b/java.html.markdown index ba602d2e..35ec57d8 100644 --- a/java.html.markdown +++ b/java.html.markdown @@ -6,6 +6,7 @@ contributors: - ["Madison Dickson", "http://github.com/mix3d"] - ["Simon Morgan", "http://sjm.io/"] - ["Zachary Ferguson", "http://github.com/zfergus2"] + - ["Cameron Schermerhorn", "http://github.com/cschermerhorn"] filename: LearnJava.java --- @@ -95,11 +96,13 @@ public class LearnJava { // Note: Java has no unsigned types. // Float - Single-precision 32-bit IEEE 754 Floating Point + // 2^-149 <= float <= (2-2^-23) * 2^127 float fooFloat = 234.5f; // f or F is used to denote that this variable value is of type float; // otherwise it is treated as double. // Double - Double-precision 64-bit IEEE 754 Floating Point + // 2^-1074 <= x <= (2-2^-52) * 2^1023 double fooDouble = 123.4; // Boolean - true & false @@ -114,7 +117,35 @@ public class LearnJava { // but they can be initialized later. final double E; E = 2.71828; + + + // BigInteger - Immutable arbitrary-precision integers + // + // BigInteger is a data type that allows programmers to manipulate + // integers longer than 64-bits. Integers are stored as an array of + // of bytes and are manipulated using functions built into BigInteger + // + // BigInteger can be initialized using an array of bytes or a string. + BigInteger fooBigInteger = new BigDecimal(fooByteArray); + + + // BigDecimal - Immutable, arbitrary-precision signed decimal number + // + // A BigDecimal takes two parts: an arbitrary precision integer + // unscaled value and a 32-bit integer scale + // + // BigDecimal allows the programmer complete control over decimal + // rounding. It is recommended to use BigDecimal with currency values + // and where exact decimal percision is required. + // + // BigDecimal can be initialized with an int, long, double or String + // or by initializing the unscaled value (BigInteger) and scale (int). + + BigDecimal fooBigDecimal = new BigDecimal(fooBigInteger, fooInt); + + + // Strings String fooString = "My String Is Here!"; @@ -286,6 +317,23 @@ public class LearnJava { break; } System.out.println("Switch Case Result: " + monthString); + + // Starting in Java 7 and above, switching Strings works like this: + String myAnswer = "maybe"; + switch(myAnswer){ + case "yes": + System.out.println("You answered yes."); + break; + case "no": + System.out.println("You answered no."); + break; + case "maybe": + System.out.println("You answered maybe."); + break; + default: + System.out.println("You answered " + myAnswer); + break; + } // Conditional Shorthand // You can use the '?' operator for quick assignments or logic forks. @@ -348,7 +396,7 @@ public class LearnJava { validCodes.add("FINLAND"); } - // But there's a nifty way to achive the same thing in an + // But there's a nifty way to achieve the same thing in an // easier way, by using something that is called Double Brace // Initialization. @@ -358,9 +406,9 @@ public class LearnJava { add("FINLAND"); }} - // The first brace is creating an new AnonymousInnerClass and the - // second one declares and instance initializer block. This block - // is called with the anonymous inner class is created. + // The first brace is creating a new AnonymousInnerClass and the + // second one declares an instance initializer block. This block + // is called when the anonymous inner class is created. // This does not only work for Collections, it works for all // non-final classes. @@ -368,7 +416,7 @@ public class LearnJava { } // End LearnJava class -// You can include other, non-public outer-level classes in a .java file, +// You can include other, non-public outer-level classes in a .java file, // but it is good practice. Instead split classes into separate files. @@ -389,7 +437,7 @@ class Bicycle { // Constructors are a way of creating classes // This is a constructor public Bicycle() { - // You can also call another constructor: + // You can also call another constructor: // this(1, 50, 5, "Bontrager"); gear = 1; cadence = 50; @@ -489,6 +537,7 @@ public interface Digestible { // We can now create a class that implements both of these interfaces. public class Fruit implements Edible, Digestible { + @Override public void eat() { // ... @@ -504,6 +553,7 @@ public class Fruit implements Edible, Digestible { // interfaces. For example: public class ExampleClass extends ExampleClassParent implements InterfaceOne, InterfaceTwo { + @Override public void InterfaceOneMethod() { } @@ -511,6 +561,7 @@ public class ExampleClass extends ExampleClassParent implements InterfaceOne, @Override public void InterfaceTwoMethod() { } + } // Abstract Classes @@ -522,10 +573,10 @@ public class ExampleClass extends ExampleClassParent implements InterfaceOne, // } // Marking a class as abstract means that it contains abstract methods that must -// be defined in a child class. Similar to interfaces, abstract classes cannot -// be instantiated, but instead must be extended and the abstract methods +// be defined in a child class. Similar to interfaces, abstract classes cannot +// be instantiated, but instead must be extended and the abstract methods // defined. Different from interfaces, abstract classes can contain a mixture of -// concrete and abstract methods. Methods in an interface cannot have a body, +// concrete and abstract methods. Methods in an interface cannot have a body, // unless the method is static, and variables are final by default, unlike an // abstract class. Also abstract classes CAN have the "main" method. @@ -541,7 +592,7 @@ public abstract class Animal age = 30; } - // No need to initialize, however in an interface + // No need to initialize, however in an interface // a variable is implicitly final and hence has // to be initialized. protected int age; @@ -569,7 +620,7 @@ class Dog extends Animal // age = 30; ==> ERROR! age is private to Animal } - // NOTE: You will get an error if you used the + // NOTE: You will get an error if you used the // @Override annotation here, since java doesn't allow // overriding of static methods. // What is happening here is called METHOD HIDING. @@ -583,7 +634,7 @@ class Dog extends Animal } } -// Final Classes +// Final Classes // Final Class declaration syntax // <access-level> final <final-class-name> { @@ -592,8 +643,8 @@ class Dog extends Animal // } // Final classes are classes that cannot be inherited from and are therefore a -// final child. In a way, final classes are the opposite of abstract classes -// because abstract classes must be extended, but final classes cannot be +// final child. In a way, final classes are the opposite of abstract classes +// because abstract classes must be extended, but final classes cannot be // extended. public final class SaberToothedCat extends Animal { |