Head First Java, 2nd Edition

Learning a complex new language is no easy task especially when it s an object-oriented computer programming language like Java. You might think the problem is your brain. It seems to have a mind of its own, a mind that doesn't always want to take in the dry, technical stuff you're forced to study. The fact is your brain craves novelty. It's constantly searching, scanning, waiting for something unusual to happen. After all, that's the way it was built to help you stay alive. It takes all the routine, ordinary, dull stuff and filters it to the background so it won't interfere with your brain's real work--recording things that matter. How does your brain know what matters? It's like the creators of the Head First approach say, suppose you're out for a hike and a tiger jumps in front of you, what happens in your brain? Neurons fire. Emotions crank up. Chemicals surge. That's how your brain knows. And that's how your brain will learn Java. __Head First Java__ combines puzzles, strong visuals, mysteries, and soul-searching interviews with famous Java objects to engage you in many different ways. It's fast, it's fun, and it's effective. And, despite its playful appearance, Head First Java is serious stuff: a complete introduction to object-oriented programming and Java. You'll learn everything from the fundamentals to advanced topics, including threads, network sockets, and distributed programming with RMI. And the new. second edition focuses on Java 5.0, the latest version of the Java language and development platform. Because Java 5.0 is a major update to the platform, with deep, code-level changes, even more careful study and implementation is required. So learning the Head First way is more important than ever. If you've read a Head First book, you know what to expect--a visually rich format designed for the way your brain works. If you haven't, you're in for a treat. You'll see why people say it's unlike any other Java book you've ever read. By exploiting how your brain works, __Head First Java__ compresses the time it takes to learn and retain--complex information. Its unique approach not only shows you what you need to know about Java syntax, it teaches you to think like a Java programmer. If you want to be bored, buy some other book. But if you want to understand Java, this book's for you. Table of Contents......Page 11 Intro.: How to Use This Book......Page 23 Who is this book for?......Page 24 And we know what your brain is thinking.......Page 25 Metacognition: thinking about thinking.......Page 27 Here’s what WE did:......Page 28 Here’s what YOU can do to bend your brain into submission.......Page 29 What you need for this book:......Page 30 Last-minute things you need to know:......Page 31 Technical Editors......Page 32 Other people to credit......Page 33 Just when you thought there wouldn’t be anymore acknowledgements*.......Page 34 Chapter 1. Dive in A Quick Dip: Breaking the Surface......Page 35 The Way Java Works......Page 36 What you’ll do in Java......Page 37 Code structure in Java......Page 41 Anatomy of a class......Page 42 Writing a class with a main......Page 43 Conditional branching......Page 47 Coding a Serious Business Application......Page 48 Phrase-O-Matic......Page 51 Chapter 2. Classes and Objects: A Trip to Objectville......Page 61 Chair Wars......Page 62 Making your first object......Page 70 Making and testing Movie objects......Page 71 Quick! Get out of main!......Page 72 Running the Guessing Game......Page 74 Chapter 3. Primitives and References: Know Your Variables......Page 83 Declaring a variable......Page 84 “I’d like a double mocha, no, make it an int.”......Page 85 You really don’t want to spill that.........Page 86 This table reserved.......Page 87 Controlling your Dog object......Page 88 An object reference is justanother variable value.......Page 89 Arrays are objects too......Page 93 Make an array of Dogs......Page 94 Control your Dog......Page 95 A Heap o’ Trouble......Page 100 Chapter 4. Methods Use Instance Variables: How Objects Behave......Page 105 Remember: a class describes what an object knows and what an object does......Page 106 The size affects the bark......Page 107 You can send things to a method......Page 108 You can get things back from a method.......Page 109 You can send more than one thing to a method......Page 110 Cool things you can do with parameters and return types......Page 113 Encapsulation......Page 114 Encapsulating the GoodDog class......Page 116 How do objects in an array behave?......Page 117 Declaring and initializing instance variables......Page 118 The difference bet ween instance and local variables......Page 119 Comparing variables (primitives or references)......Page 120 Chapter 5. Writing a Program: Extra-Strength Methods......Page 129 Let’s build a Battleship-style game: “Sink a Dot Com”......Page 130 First, a high-level design......Page 131 The “Simple Dot Com Game” a gentler introduction......Page 132 Developing a Class......Page 133 The checkYourself() method......Page 138 The game’s main() method......Page 144 More about for loops......Page 148 Trips through a loop......Page 149 The enhanced for loop......Page 150 Chapter 6. Get to Know The Java API: Using the Java Library......Page 159 In our last chapter, we left you with the cliff-hanger. A bug.......Page 160 So what happened?......Page 161 How do we fix it ?......Page 162 Option t wo is a little better, but still pretty clunky......Page 163 Wake up and smell the library......Page 166 Some things you can do with ArrayList......Page 167 Comparing ArrayList to a regular array......Page 170 Let’s fix the DotCom code.......Page 172 New and improved DotCom class......Page 173 Let’s build the REAL game: “Sink a Dot Com”......Page 174 What needs to change?......Page 175 Who does what in the DotComBust game (and when)......Page 176 Prep code for the real DotComBust class......Page 178 The final version of the DotCom class......Page 184 Super Powerful Boolean Expressions......Page 185 Using the Library (the Java API)......Page 188 You have to know the full name* of the class you want to use in your code.......Page 189 How to play with the API......Page 192 Chapter 7. Inheritance and Polymorphism: Better Living in Objectville......Page 199 Chair Wars Revisited.........Page 200 Understanding Inheritance......Page 202 Let’s design the inheritance tree for an Animal simulation program......Page 204 Using inheritance to avoid duplicating code in subclasses......Page 205 Do all animals eat the same way?......Page 206 Looking for more inheritance opportunities......Page 207 Which method is called?......Page 209 Designing an Inheritance Tree......Page 210 Using IS-A and HAS-A......Page 211 But wait! There’s more!......Page 212 How do you know if you’ve got your inheritance right?......Page 213 When designing with inheritance, are you using or abusing?......Page 215 Keeping the contract: rules for overriding......Page 224 Overloading a method......Page 225 Chapter 8. Interfaces and Abstract Classes......Page 231 Did we forget about something when we designed this?......Page 232 What does a new Animal() object look like?......Page 234 The compiler won’t let you instantiate an abstract class......Page 235 Abstract vs. Concrete......Page 236 Abstract methods......Page 237 You MUST implement all abstract methods......Page 238 Polymorphism in action......Page 240 Uh-oh, now we need to keep Cats, too.......Page 241 What about non-Animals? Why not make a class generic enough to take anything?......Page 242 So what’s in this ultra-super-megaclass Object?......Page 243 Using polymorphic references of type Object has a price.........Page 245 When a Dog won’t act like a Dog......Page 246 Objects don’t bark.......Page 247 Get in touch with your inner Object.......Page 248 What if you need to change the contract?......Page 252 Let’s explore some design options for reusing some of our existing classes in a PetShop program.......Page 253 Interface to the rescue!......Page 258 Making and Implementing the Pet interface......Page 259 Chapter 9. Constructors and Garbage Collection: Life and Death of an Object......Page 269 The Stack and the Heap: where things live......Page 270 Methods are stacked......Page 271 What about local variables that are objects?......Page 272 If local variables live on the stack, where do instance variables live?......Page 273 The miracle of object creation......Page 274 Construct a Duck......Page 276 Initializing the state of a new Duck......Page 277 Using the constructor to initialize important Duck state*......Page 278 Make it easy to make a Duck......Page 279 Doesn’t the compiler always make a no-arg constructor for you?......Page 280 Nanoreview: four things to remember about constructors......Page 283 Wait a minute... we never DID talk about superclasses and inheritance and how that all fits in with constructors.......Page 284 The role of superclass constructors in an object’s life.......Page 285 Making a Hippo means making the Animal and Object parts too.........Page 286 How do you invoke a superclass constructor?......Page 287 Can the child exist before the parents?......Page 288 Superclass constructors with arguments......Page 289 Invoking one overloaded constructor from another......Page 290 Now we know how an object is born, but how long does an object live ?......Page 292 What about reference variables?......Page 294 Chapter 10. Numbers and Statics: Numbers Matter......Page 307 MATH methods: as close as you’ll ever get to a global method......Page 308 The difference between regular (non-static) and static methods......Page 309 What it means to have a class with static methods.......Page 310 Static methods can’t use non-static (instance) variables!......Page 311 Static methods can’t use non-static methods, either!......Page 312 Static variable: value is the same for ALL instances of the class......Page 313 Initializing a static variable......Page 315 static final variables are constants......Page 316 final isn’t just for static variables.........Page 317 Math methods......Page 320 Wrapping a primitive......Page 321 Before Java 5.0, YOU had to do the work.........Page 322 Autoboxing: blurring the line between primitive and object......Page 323 Autoboxing works almost everywhere......Page 324 But wait! There’s more! Wrappers have static utility methods too!......Page 326 And now in reverse... turning a primitive number into a String......Page 327 Number formatting......Page 328 Formatting deconstructed.........Page 329 The percent (%) says, “insert argument here”......Page 330 The format String uses its own little language syntax......Page 331 The format specifier......Page 332 The only required specifier is for TYPE......Page 333 What happens if I have more than one argument?......Page 334 So much for numbers, what about dates?......Page 335 Moving backward and forward in time......Page 337 Getting an object that extends Calendar......Page 338 Working with Calendar objects......Page 339 Highlights of the Calendar API......Page 340 Even more Statics!... static imports......Page 341 Chapter 11. Exception Handling: Risky Behavior......Page 349 Let’s make a Music Machine......Page 350 We’ll start with the basics......Page 351 First we need a Sequencer......Page 352 What happens when a method you want to call (probably in a class you didn’t write) is risky?......Page 353 Methods in Java use exceptions to tell the calling code, “Something Bad Happened. I failed.”......Page 354 The compiler needs to know that YOU know you’re calling a risky method.......Page 355 An exception is an object... of type Exception.......Page 356 If it’s your code that catches the exception, then whose code throws it?......Page 357 Flow control in try/catch blocks......Page 360 Finally: for the things you want to do no matter what.......Page 361 Did we mention that a method can throw more than one exception?......Page 363 Exceptions are polymorphic......Page 364 Multiple catch blocks must be ordered from smallest to biggest......Page 366 You can’t put bigger baskets above smaller baskets.......Page 367 When you don’t want to handle an exception.........Page 369 Ducking (by declaring) only delays the inevitable......Page 370 Getting back to our music code.........Page 372 Making actual sound......Page 374 Your very first sound player app......Page 376 Making a MidiEvent (song data)......Page 377 MIDI message: the heart of a MidiEvent......Page 378 Change a message......Page 379 Chapter 12. Getting GUI: A Very Graphic Story......Page 387 It all starts with a window......Page 388 Your first GUI: a button on a frame......Page 389 But nothing happens when I click it.........Page 390 Getting a user event......Page 391 Listeners, Sources, and Events......Page 395 Getting back to graphics.........Page 397 Make your own drawing widget......Page 398 Fun things to do in paintComponent()......Page 399 Behind every good Graphics reference is a Graphics2D object.......Page 400 Because life’s too short to paint the circle a solid color when there’s a gradient blend waiting for you.......Page 401 We can get an event. We can paint graphics. But can we paint graphics when we get an event?......Page 403 GUI layouts: putting more than one widget on a frame......Page 404 Let’s try it with TWO buttons......Page 406 Inner class to the rescue!......Page 410 An inner class instance must be tied to an outer class instance*.......Page 411 How to make an instance of an inner class......Page 412 Using an inner class for animation......Page 416 Listening for a non-GUI event......Page 421 An easier way to make messages / events......Page 422 Example: how to use the new static makeEvent() method......Page 423 Version Two: registering and getting ControllerEvents......Page 424 Version Three: drawing graphics in time with the music......Page 425 Chapter 13. Using Swing: Work on Your Swing......Page 433 Swing components......Page 434 Layout Managers......Page 435 How does the layout manager decide?......Page 436 The Big Three layout managers: border, flow, and box.......Page 437 Playing with Swing components......Page 447 Making the BeatBox......Page 453 Chapter 14. Serialization and File I/O: Saving Objects......Page 463 Capture the Beat......Page 464 Saving State......Page 465 Writing a serialized object to a file......Page 466 Data moves in streams from one place to another.......Page 467 What really happens to an object when it’s serialized?......Page 468 But what exactly IS an object’s state?What needs to be saved?......Page 469 If you want your class to be serializable, implement Serializable......Page 471 Deserialization: restoring an object......Page 475 What happens during deserialization?......Page 476 Saving and restoring the game characters......Page 478 Writing a String to a Text File......Page 481 Text File Example: e-Flashcards......Page 482 Quiz Card Builder (code outline)......Page 483 The java.io.File class......Page 486 Reading from a Text File......Page 488 Quiz Card Player (code outline)......Page 489 Parsing with String split()......Page 492 Version ID: A Big Serialization Gotcha......Page 494 Using the serialVersionUID......Page 495 Saving a BeatBox pattern......Page 497 Restoring a BeatBox pattern......Page 498 Chapter 15. Networking and Threads: Make a Connection......Page 505 Real-time Beat Box Chat......Page 506 Connecting, Sending, and Receiving......Page 508 Make a net work Socket connection......Page 509 A TCP port is just a number.......Page 510 To read data from a Socket, use a BufferedReader......Page 512 To write data to a Socket, use a PrintWriter......Page 513 The DailyAdviceClient......Page 514 DailyAdviceClient code......Page 515 Writing a simple server......Page 517 DailyAdviceServer code......Page 518 Writing a Chat Client......Page 520 Java has multiple threads but only one Thread class......Page 524 What does it mean to have more than one call stack?......Page 525 Every Thread needs a job to do. A method to put on the new thread stack.......Page 527 To make a job for your thread, implement the Runnable interface......Page 528 The Thread Scheduler......Page 531 Putting a thread to sleep......Page 535 Using sleep to make our program more predictable.......Page 536 What will happen?......Page 537 Um, yes. There IS a dark side. Threads can lead to concurrency 'issues'.......Page 538 The Ryan and Monica problem, in code......Page 540 We need the makeWithdrawal ( ) method to run as one atomic thing.......Page 544 Using an object’s lock......Page 545 The dreaded “Lost Update” problem......Page 546 Let’s run this code.........Page 547 Make the increment() method atomic. Synchronize it!......Page 548 The deadly side of synchronization......Page 550 New and improved SimpleChatClient......Page 552 The really really simple Chat Server......Page 554 Chapter 16. Collections and Generics: Data Structures......Page 563 Tracking song popularity on your jukebox......Page 564 Here’s what you have so far, without the sort:......Page 565 But the ArrayList class does NOT have a sort() method!......Page 566 ArrayList is not the only collection......Page 567 You could use a TreeSet... Or you could use the Collections.sort() method......Page 568 Adding Collections.sort() to the Jukebox code......Page 569 But now you need Song objects, not just simple Strings.......Page 570 Changing the Jukebox code to use Songs instead of Strings......Page 571 It won’t compile !......Page 572 Generics means more type-safety......Page 574 Learning generics......Page 575 Using generic CLASSES......Page 576 Using type parameters with ArrayList......Page 577 Using generic METHODS......Page 578 Here’s where it gets weird.........Page 579 Revisiting the sort( ) method......Page 581 In generics, “extends” means“ extends or implements”......Page 582 Finally we know what’s wrong... The Song class needs to implement Comparable......Page 583 The new, improved, comparable Song class......Page 584 We can sort the list, but.........Page 585 Using a custom Comparator......Page 586 Updating the Jukebox to use a Comparator......Page 587 Uh-oh. The sorting all works, but now we have duplicates.........Page 590 We need a Set instead of a List......Page 591 The Collection API (part of it)......Page 592 Using a HashSet instead of ArrayList......Page 593 What makes t wo objects equal?......Page 594 How a HashSet checks for duplicates: hashCode() and equals()......Page 595 The Song class with overridden hashCode() and equals()......Page 596 And if we want the set to stay sorted, we’ve got TreeSet......Page 598 What you MUST know about TreeSet.........Page 599 TreeSet elements MUST be comparable......Page 600 We’ve seen Lists and Sets, now we’ll use a Map......Page 601 Finally, back to generics......Page 602 Using polymorphic arguments and generics......Page 603 But will it work with ArrayList ?......Page 604 What could happen if it were allowed.........Page 605 Wildcards to the rescue......Page 608 Alternate syntax for doing the same thing......Page 609 Chapter 17. Package, Jars and Deployment: Release Your Code......Page 615 Deploying your application......Page 616 Separate source code and class files......Page 618 Put your Java in a JAR......Page 619 Running (executing) the JAR......Page 620 Put your classes in packages!......Page 621 Preventing package name conflicts......Page 622 Compiling and running with packages......Page 624 The -d flag is even cooler than we said......Page 625 Making an executable JAR with packages......Page 626 So where did the manifest file go?......Page 627 Java Web Start......Page 631 The .jnlp file......Page 633 Chapter 18. Remote Deployment with RMI: Distributed Computing......Page 641 Method calls are always between two objects on the same heap.......Page 642 What if you want to invoke a method on an object running on another machine?......Page 643 But you can’t do that.......Page 644 The role of the ‘helpers’......Page 646 Java RMI gives you the client and service helper objects!......Page 648 How does the client get the stub object?......Page 654 How does the client get the stub class?......Page 655 Be sure each machine has the class files it needs.......Page 656 Yeah, but who really uses RMI?......Page 658 What about Servlets?......Page 659 Just for fun, let’s make the Phrase-O-Matic work as a servlet......Page 663 Phrase-O-Matic code, servlet-friendly......Page 664 Enterprise JavaBeans: RMI on steroids......Page 665 For our final trick... a little Jini......Page 666 Final Project: the Universal Service browser......Page 670 Appendix A:Final Code Kitchen......Page 683 Final BeatBox client program......Page 684 Final BeatBox server program......Page 691 Appendix B: The Top Ten Topics that almost made it into the Real Book.........Page 693 #10 Bit Manipulation......Page 694 #9 Immutability......Page 695 #8 Assertions......Page 696 #7 Block Scope......Page 697 #6 Linked Invocations......Page 698 #5 Anonymous and Static Nested Classes......Page 699 #5 Anonymous and Static Nested Classes, continued......Page 700 #4 Access Levels and Access Modifiers (Who Sees What)......Page 701 #4 Access Levels and Access Modifiers, cont.......Page 702 #3 String and StringBuffer/StringBuilder Methods......Page 703 #2 Multidimensional Arrays......Page 704 #1 Enumerations (also called Enumerated Types or Enums)......Page 705 A......Page 711 C......Page 712 E......Page 713 G......Page 714 I......Page 715 L......Page 716 O......Page 717 P......Page 718 S......Page 719 W......Page 721 Intro Breaking the Surface: a quick dip A Trip to Objectville: yes, there will be objects Know Your Variables: primitives and references How Objects Behave: object state affects method behavior Extra-Strength Methods: flow control, operations, and more Using the Java Library: so you don't have to write it all yourself Better Living in Objectville: planning for the future Serious Polymorphism: exploiting abstract classes and interfaces Life and Death of an Object: constructors and memory management Numbers Matter: math, formattng, wrappers, and statics Risky Behavior: exception handling A Very Graphic Story: intro to GUI, event handling, and inner classes Work on Your Swing: layout managers and components Saving Objets: serialization and I/O Make a Connection: networking sockets and multithreading Data Structures: collections and generics Release Your Code: packaging and deployment Distributed Computing: RMI with a dash of servlets, EJB, and Jini Appendix A: Final code kitchen Appendix B: Top Ten Things that didn't make it into the rest of the book Index "Learning a complex new language is no easy task, especially when it's an object-oriented computer programming language like Java. Your brain doesn't always want to take in the dry, technical stuff you're forced to study. Your brain craves novelty. Head First Java combines puzzles, strong visuals, mysteries, and soul-searching interviews with famous Java objects to engage you in many different ways. Despite its playful appearance, Head First Java is serious: a complete introduction to object-oriented programming and Java. Its unique approach not only shows you what you need to know about Java syntax, it teaches you to think like a Java programmer. You'll learn everything from the fundamentals to advanced topics, including threads, network sockets, and distributed programming with RMI. The second edition focuses on Java 5.0, a major update to the platform, with deep, code-level changes."--Résumé de l'éditeur