Java Notes for Professionals

Content list......Page 2
About......Page 25
Section 1.1: Creating Your First Java Program......Page 26
Section 2.3: Non-numeric primitive casting......Page 32
Section 2.5: Testing if an object can be cast using instanceof......Page 33
Section 3.2: Why Use Getters and Setters?......Page 34
Section 3.3: Adding Getters and Setters......Page 35
Section 4.2: Instantiating a reference type......Page 37
Section 5.1: The 'javac' command - getting started......Page 38
Section 5.2: Compiling for a dierent version of Java......Page 40
Section 6.2: Class Documentation......Page 42
Section 6.3: Method Documentation......Page 43
Section 6.5: Links......Page 44
Section 6.6: Code snippets inside documentation......Page 45
Section 6.8: Inline Code Documentation......Page 46
Section 7.2: Processing arguments by hand......Page 48
Section 8.2: Troubleshooting the 'java' command......Page 51
Section 8.3: Running a Java application with library dependencies......Page 53
Section 8.4: Java Options......Page 54
Section 8.5: Spaces and other special characters in arguments......Page 55
Section 8.7: Running a Java applications via a "main" class......Page 57
Section 9.2: Hexadecimal, Octal and Binary literals......Page 59
Section 9.4: String literals......Page 60
Section 9.6: Escape sequences in literals......Page 61
Section 9.8: Decimal Integer literals......Page 62
Section 9.9: Floating-point literals......Page 63
Section 10.2: Primitive Types Cheatsheet......Page 66
Section 10.3: The float primitive......Page 67
Section 10.4: The int primitive......Page 68
Section 10.6: Memory consumption of primitives vs. boxed primitives......Page 69
Section 10.7: The double primitive......Page 70
Section 10.8: The long primitive......Page 71
Section 10.10: The byte primitive......Page 72
Section 10.11: Negative value representation......Page 73
Section 10.12: The short primitive......Page 74
Section 11.1: Comparing Strings......Page 75
Section 11.2: Changing the case of characters within a String......Page 77
Section 11.3: Finding a String Within Another String......Page 79
Section 11.4: String pool and heap storage......Page 80
Section 11.5: Splitting Strings......Page 81
Section 11.6: Joining Strings with a delimiter......Page 83
Section 11.7: String concatenation and StringBuilders......Page 84
Section 11.8: Substrings......Page 85
Section 11.10: Reversing Strings......Page 86
Section 11.11: Adding toString() method for custom objects......Page 87
Section 11.13: Case insensitive switch......Page 88
Section 11.14: Replacing parts of Strings......Page 89
Section 11.17: Counting occurrences of a substring or character in a string......Page 90
Section 12.1: String Buer class......Page 92
Section 13.1: Comparing StringBuer, StringBuilder, Formatter and StringJoiner......Page 93
Section 13.2: Repeat a String n times......Page 94
Section 14.2: StringTokenizer Split by comma ','......Page 95
Section 15.2: Break a string up into substrings all of variable length......Page 96
Section 16.2: A basic date output......Page 97
Section 16.3: Java 8 LocalDate and LocalDateTime objects......Page 98
Section 16.5: Converting Date to a certain String format......Page 99
Section 16.7: Convert formatted string representation of date to Date object......Page 100
Section 16.9: Comparing Date objects......Page 101
Section 16.11: Time Zones and java.util.Date......Page 104
Section 17.4: Instant......Page 106
Section 17.5: Usage of various classes of Date Time API......Page 107
Section 17.7: Simple Date Manipulations......Page 109
Section 18.1: Amount of time between two LocalTime......Page 111
Section 18.4: Time Zones and their time dierence......Page 112
Section 19.2: Using BigDecimal instead of float......Page 114
Section 19.4: Mathematical operations with BigDecimal......Page 115
Section 19.6: BigDecimal objects are immutable......Page 118
Section 20.1: Initialization......Page 120
Section 20.2: BigInteger Mathematical Operations Examples......Page 121
Section 20.3: Comparing BigIntegers......Page 123
Section 20.4: Binary Logic Operations on BigInteger......Page 124
Section 20.5: Generating random BigIntegers......Page 125
Section 21.1: NumberFormat......Page 127
Section 22.2: java.util.BitSet class......Page 128
Section 22.3: Checking if a number is a power of 2......Page 129
Section 22.5: Expressing the power of 2......Page 131
Section 22.6: Packing / unpacking values as bit fragments......Page 132
Section 23.1: Creating and Initializing Arrays......Page 133
Section 23.2: Creating a List from an Array......Page 139
Section 23.4: Multidimensional and Jagged Arrays......Page 141
Section 23.5: ArrayIndexOutOfBoundsException......Page 143
Section 23.6: Array Covariance......Page 144
Section 23.8: Iterating over arrays......Page 145
Section 23.9: Arrays to a String......Page 147
Section 23.10: Sorting arrays......Page 148
Section 23.12: Finding an element in an array......Page 150
Section 23.13: How do you change the size of an array?......Page 151
Section 23.14: Converting arrays between primitives and boxed types......Page 152
Section 23.15: Remove an element from an array......Page 153
Section 23.17: Copying arrays......Page 154
Section 23.18: Casting Arrays......Page 155
Section 24.1: Removing items from a List within a loop......Page 157
Section 24.2: Constructing collections from existing data......Page 159
Section 24.4: Iterating over Collections......Page 161
Section 24.6: Sub Collections......Page 163
Section 24.7: Unmodifiable Collection......Page 164
Section 24.9: Removing matching items from Lists using Iterator......Page 165
Section 24.11: Creating your own Iterable structure for use with Iterator or for-each loop......Page 166
Section 24.12: Collections and Primitive Values......Page 168
Section 25.1: Sorting a generic list......Page 170
Section 25.3: Classes implementing List - Pros and Cons......Page 171
Section 25.5: In-place replacement of a List element......Page 174
Section 25.7: Moving objects around in the list......Page 175
Section 25.9: Creating a List......Page 176
Section 25.10: Positional Access Operations......Page 177
Section 25.12: Removing elements from list B that are present in the list A......Page 179
Section 26.2: Basics of Set......Page 181
Section 26.3: Types and Usage of Sets......Page 182
Section 26.5: Eliminating duplicates using Set......Page 183
Section 26.6: Declaring a HashSet with values......Page 184
Section 27.1: List vs Set......Page 185
Section 28.1: Iterating Map Entries Eciently......Page 186
Section 28.2: Usage of HashMap......Page 188
Section 28.3: Using Default Methods of Map from Java 8......Page 189
Section 28.4: Iterating through the contents of a Map......Page 191
Section 28.5: Merging, combine and composing Maps......Page 192
Section 28.6: Add multiple items......Page 193
Section 28.7: Creating and Initializing Maps......Page 195
Section 28.9: Add an element......Page 196
Section 28.11: Use custom object as key......Page 197
Section 29.1: Java LinkedHashMap class......Page 199
Section 30.1: Concepts of WeakHashmap......Page 200
Section 31.1: Introduction to sorted Map......Page 201
Section 32.2: TreeSet of a simple Java Type......Page 202
Section 32.3: TreeMap/TreeSet of a custom Java type......Page 203
Section 32.4: TreeMap and TreeSet Thread Safety......Page 204
Section 33.2: Deque......Page 206
Section 33.3: Stacks......Page 207
Section 33.4: BlockingQueue......Page 208
Section 33.5: LinkedList as a FIFO Queue......Page 209
Section 33.6: Queue Interface......Page 210
Section 34.4: Iterating through Deque......Page 211
Section 35.1: Declaring and using a basic enum......Page 213
Section 35.2: Enums with constructors......Page 216
Section 35.3: Enums with Abstract Methods......Page 217
Section 35.4: Implements Interface......Page 218
Section 35.5: Implement Singleton pattern with a single-element enum......Page 219
Section 35.7: Zero instance enum......Page 220
Section 35.9: Documenting enums......Page 221
Section 35.10: Enum constant specific body......Page 222
Section 35.11: Getting the values of an enum......Page 223
Section 35.12: Enum Polymorphism Pattern......Page 224
Section 35.14: Get enum constant by name......Page 225
Section 35.15: Enum with properties (fields)......Page 226
Section 35.17: Enums with static fields......Page 227
Section 36.1: Enum Map Book Example......Page 229
Section 37.1: Enum Set Example......Page 230
Section 38.1: Enum with name at beginning......Page 231
Section 39.1: Hashtable......Page 232
Section 40.2: The Conditional Operator (? :)......Page 233
Section 40.3: The Bitwise and Logical Operators (~, &, |, ^)......Page 235
Section 40.4: The String Concatenation Operator (+)......Page 236
Section 40.5: The Arithmetic Operators (+, -, *, /, %)......Page 238
Section 40.6: The Shift Operators (<<, >> and >>>)......Page 240
Section 40.7: The Instanceof Operator......Page 241
Section 40.8: The Assignment Operators (=, +=, -=, *=, /=, %=, <<=, >>= , >>>=, &=, |= and ^=)......Page 242
Section 40.9: The conditional-and and conditional-or Operators ( && and || )......Page 244
Section 40.10: The Relational Operators (<, <=, >, >=)......Page 245
Section 40.11: The Equality Operators (==, !=)......Page 246
Section 40.12: The Lambda operator ( -> )......Page 248
Section 41.1: Default Constructor......Page 249
Section 41.2: Call parent constructor......Page 250
Section 41.3: Constructor with Arguments......Page 251
Section 42.1: hashCode() method......Page 253
Section 42.2: toString() method......Page 255
Section 42.3: equals() method......Page 256
Section 42.4: wait() and notify() methods......Page 258
Section 42.5: getClass() method......Page 260
Section 42.6: clone() method......Page 261
Section 42.7: Object constructor......Page 262
Section 42.8: finalize() method......Page 263
Section 43.2: Defining annotation types......Page 265
Section 43.4: Built-in annotations......Page 267
Section 43.5: Compile time processing using annotation processor......Page 270
Section 43.6: Repeating Annotations......Page 274
Section 43.7: Inherited Annotations......Page 275
Section 43.8: Getting Annotation values at run-time......Page 276
Section 43.9: Annotations for 'this' and receiver parameters......Page 277
Section 43.10: Add multiple annotation values......Page 278
Section 44.3: Rules to define immutable classes......Page 279
Section 44.4: Example with mutable refs......Page 280
Section 45.2: The recipe for an immutable class......Page 281
Section 45.3: Typical design flaws which prevent a class from being immutable......Page 282
Section 46.2: Public Visibility......Page 286
Section 46.4: Protected Visibility......Page 287
Section 46.6: Interface members......Page 288
Section 47.1: Creating a Generic Class......Page 289
Section 47.2: Deciding between `T`, `? super T`, and `? extends T`......Page 291
Section 47.4: Declaring a Generic Method......Page 293
Section 47.6: Obtain class that satisfies generic parameter at runtime......Page 294
Section 47.7: Benefits of Generic class and interface......Page 295
Section 47.9: Creating a Bounded Generic Class......Page 296
Section 47.10: Referring to the declared generic type within its own declaration......Page 298
Section 47.11: Binding generic parameter to more than 1 type......Page 299
Section 47.13: Use of instanceof with Generics......Page 300
Section 47.14: Dierent ways for implementing a Generic Interface (or extending a Generic Class)......Page 302
Section 48.1: Overloading Methods......Page 304
Section 48.2: Explaining what is method overloading and overriding......Page 305
Section 48.3: Constructors......Page 307
Section 48.4: Initializing static final fields using a static initializer......Page 308
Section 48.5: Basic Object Construction and Use......Page 309
Section 48.7: Object Member vs Static Member......Page 311
Section 49.1: Local Inner Class......Page 313
Section 50.2: Static vs Non Static Nested Classes......Page 314
Section 50.3: Access Modifiers for Inner Classes......Page 316
Section 50.4: Anonymous Inner Classes......Page 317
Section 50.5: Create instance of non-static inner class from outside......Page 318
Section 50.7: Accessing the outer class from a non-static inner class......Page 319
Section 51.2: Objects.nonNull() method reference use in stream api......Page 321
Section 52.2: Accessing overridden default methods from implementing class......Page 322
Section 52.4: Accessing other interface methods within default method......Page 323
Section 52.5: Default method multiple inheritance collision......Page 324
Section 52.6: Class, Abstract class and Interface method precedence......Page 325
Section 53.2: Using Package Protected Scope......Page 327
Section 54.1: Inheritance......Page 329
Section 54.2: Abstract Classes......Page 330
Section 54.3: Using 'final' to restrict inheritance and overriding......Page 332
Section 54.4: The Liskov Substitution Principle......Page 333
Section 54.5: Abstract class and Interface usage: "Is-a" relation vs "Has-a" capability......Page 334
Section 54.6: Static Inheritance......Page 337
Section 54.7: Programming to an interface......Page 338
Section 54.8: Overriding in Inheritance......Page 340
Section 54.10: Narrowing and Widening of object references......Page 341
Section 54.11: Inheritance and Static Methods......Page 342
Section 55.1: Dierent Reference Types......Page 344
Section 56.1: Reading user input from the console......Page 346
Section 56.2: Aligning strings in console......Page 347
Section 56.3: Implementing Basic Command-Line Behavior......Page 348
Section 57.1: Using Streams......Page 350
Section 57.2: Consuming Streams......Page 352
Section 57.4: Infinite Streams......Page 354
Section 57.5: Collect Elements of a Stream into a Collection......Page 355
Section 57.7: Flatten Streams with flatMap()......Page 358
Section 57.8: Parallel Stream......Page 359
Section 57.9: Creating a Stream......Page 360
Section 57.12: Using IntStream to iterate over indexes......Page 361
Section 57.14: Reduction with Streams......Page 362
Section 57.17: Finding the First Element that Matches a Predicate......Page 365
Section 57.18: Using Streams and Method References to Write Self-Documenting Processes......Page 366
Section 57.21: Create a Map based on a Stream......Page 367
Section 57.22: Joining a stream to a single String......Page 368
Section 57.23: Sort Using Stream......Page 369
Section 57.25: Stream operations categories......Page 370
Section 57.27: Generating random Strings using Streams......Page 371
Section 58.2: Reading InputStream into a String......Page 373
Section 58.3: Wrapping Input/Output Streams......Page 374
Section 58.6: Copying Input Stream to Output Stream......Page 375
Section 59.1: BueredReader......Page 377
Section 59.2: StringWriter Example......Page 378
Section 60.2: Adding event listeners......Page 379
Section 60.3: Getting sub-nodes of Preferences......Page 380
Section 60.5: Exporting preferences......Page 381
Section 60.6: Importing preferences......Page 382
Section 60.7: Removing event listeners......Page 383
Section 60.9: Setting preferences values......Page 384
Section 61.3: Map Factory Method Examples......Page 385
Section 62.1: Multimap in Guava, Apache and Eclipse Collections......Page 386
Section 62.2: Apache HashBag, Guava HashMultiset and Eclipse HashBag......Page 388
Section 62.3: Compare operation with collections - Create collections......Page 390
Section 63.2: Insertion into ConcurrentHashMap......Page 395
Section 63.3: Concurrent Collections......Page 396
Section 64.1: Java Collections Flowchart......Page 398
Section 65.1: Super keyword use with examples......Page 399
Section 66.1: Basic Serialization in Java......Page 402
Section 66.2: Custom Serialization......Page 403
Section 66.3: Versioning and serialVersionUID......Page 406
Section 66.4: Serialization with Gson......Page 407
Section 66.5: Custom JSON Deserialization with Jackson......Page 408
Section 67.1: Map......Page 411
Section 67.4: Lazily provide a default value using a Supplier......Page 412
Section 67.6: Using Optional containers for primitive number types......Page 413
Section 67.8: FlatMap......Page 414
Section 68.1: Object References as method parameters......Page 415
Section 69.1: Catching an exception with try-catch......Page 418
Section 69.2: The try-with-resources statement......Page 419
Section 69.3: Custom Exceptions......Page 422
Section 69.4: Handling InterruptedException......Page 424
Section 69.5: Return statements in try catch block......Page 425
Section 69.6: Introduction......Page 426
Section 69.7: The Java Exception Hierarchy - Unchecked and Checked Exceptions......Page 427
Section 69.8: Creating and reading stacktraces......Page 430
Section 69.9: Throwing an exception......Page 433
Section 69.10: Advanced features of Exceptions......Page 435
Section 69.11: The try-finally and try-catch-finally statements......Page 436
Section 69.12: The 'throws' clause in a method declaration......Page 438
Section 70.4: Finding AM/PM......Page 440
Section 71.2: Using static to declare constants......Page 442
Section 72.2: Saving Properties as XML......Page 444
Section 72.3: Property files caveat: trailing whitespace......Page 445
Section 73.1: Introduction to Java lambdas......Page 448
Section 73.2: Using Lambda Expressions to Sort a Collection......Page 451
Section 73.3: Method References......Page 452
Section 73.5: Lambda - Listener Example......Page 454
Section 73.6: Java Closures with lambda expressions......Page 455
Section 73.7: Lambdas and memory utilization......Page 456
Section 73.9: Traditional style to Lambda style......Page 457
Section 73.10: `return` only returns from the lambda, not the outer method......Page 458
Section 73.12: Using lambda expressions & predicates to get a certain value(s) from a list......Page 460
Section 74.1: Switch statement......Page 462
Section 74.2: do...while Loop......Page 463
Section 74.3: For Each......Page 464
Section 74.6: For Loops......Page 465
Section 74.7: Ternary Operator......Page 466
Section 74.9: Break......Page 467
Section 74.12: Nested break / continue......Page 468
Section 75.1: Write a line of text to File......Page 470
Section 76.3: Retrieving information about a path......Page 471
Section 76.4: Retrieving information using the filesystem......Page 472
Section 76.6: Writing files......Page 473
Section 77.1: Migrating from java.io.File to Java 7 NIO (java.nio.file.Path)......Page 474
Section 77.3: File Read/Write Using FileInputStream/FileOutputStream......Page 476
Section 77.4: Reading all bytes to a byte[]......Page 477
Section 77.6: Writing a byte[] to a file......Page 478
Section 77.7: Stream vs Writer/Reader API......Page 479
Section 77.8: Reading a file with a Scanner......Page 480
Section 77.11: Reading a file using Channel and Buer......Page 481
Section 77.12: Adding Directories......Page 482
Section 77.13: Blocking or redirecting standard output / error......Page 483
Section 77.16: Reading a file using BueredInputStream......Page 484
Section 77.18: Writing a file using Channel and Buer......Page 485
Section 77.20: Iterating over a directory and filter by file extension......Page 486
Section 77.21: Accessing the contents of a ZIP file......Page 487
Section 78.1: General Pattern that does most commonly asked about tasks......Page 488
Section 78.4: Reading file input using Scanner......Page 490
Section 78.6: Carefully Closing a Scanner......Page 491
Section 78.7: Read an int from the command line......Page 492
Section 79.1: Implementing multiple interfaces......Page 493
Section 79.3: Extending an interface......Page 494
Section 79.4: Usefulness of interfaces......Page 495
Section 79.5: Default methods......Page 497
Section 79.7: Using Interfaces with Generics......Page 499
Section 79.9: Implementing interfaces in an abstract class......Page 502
Section 80.1: Using capture groups......Page 504
Section 80.3: Escape Characters......Page 505
Section 80.6: Matching a backslash......Page 506
Section 81.1: Sorting a List using Comparable or a Comparator......Page 508
Section 81.2: The compareTo and compare Methods......Page 511
Section 81.3: Natural (comparable) vs explicit (comparator) sorting......Page 512
Section 81.5: Sorting Map entries......Page 513
Section 82.1: Comparing floating point values......Page 515
Section 82.2: OverFlow and UnderFlow......Page 517
Section 82.4: Strict Adherence to the IEEE Specification......Page 518
Section 83.1: Add custom currency......Page 520
Section 84.1: Cloning performing a deep copy......Page 521
Section 84.4: Cloning by implementing Clonable interface......Page 522
Section 84.5: Cloning performing a shallow copy......Page 523
Section 85.2: Deep recursion is problematic in Java......Page 525
Section 85.4: Computing the Nth Fibonacci Number......Page 527
Section 85.5: StackOverflowError & recursion to loop......Page 528
Section 85.7: Traversing a Tree data structure with recursion......Page 530
Section 85.9: Computing the sum of integers from 1 to N......Page 531
Section 86.1: Converting String to other datatypes......Page 532
Section 86.3: Base64 Encoding / Decoding......Page 533
Section 86.4: Converting other datatypes to String......Page 534
Section 86.5: Getting a `String` from an `InputStream`......Page 535
Section 87.2: Pseudo Random Numbers in Specific Range......Page 536
Section 87.4: Generating Random Numbers with a Specified Seed......Page 537
Section 87.5: Select random numbers without duplicates......Page 538
Section 87.6: Generating Random number using apache-common lang3......Page 539
Section 88.2: Singleton without use of Enum (eager initialization)......Page 540
Section 88.4: Thread safe Singleton with double checked locking......Page 541
Section 88.5: Extending singleton (singleton inheritance)......Page 542
Section 89.1: Using int and Integer interchangeably......Page 545
Section 89.4: Dierent Cases When Integer and int can be used interchangeably......Page 546
Section 89.5: Memory and Computational Overhead of Autoboxing......Page 548
Section 90.1: Example 1: Draw and Fill a Rectangle Using Java......Page 549
Section 90.2: Example 2: Drawing and Filling Oval......Page 551
Section 91.2: Writing an XML file (marshalling an object)......Page 552
Section 91.3: Manual field/property XML mapping configuration......Page 553
Section 91.5: Using XmlAdapter to generate desired xml format......Page 554
Section 91.7: Automatic field/property XML mapping configuration (@XmlAccessorType)......Page 556
Section 91.8: Specifying a XmlAdapter instance to (re)use existing data......Page 558
Section 92.1: getClass() method of Object class......Page 561
Section 93.1: Basic Client and Server Communication using a Socket......Page 562
Section 93.2: Basic Client/Server Communication using UDP (Datagram)......Page 564
Section 93.3: Loading TrustStore and KeyStore from InputStream......Page 565
Section 93.4: Socket example - reading a web page using a simple socket......Page 566
Section 93.6: Downloading a file using Channel......Page 567
Section 93.7: Multicasting......Page 568
Section 94.1: Using Selector to wait for events (example with OP_CONNECT)......Page 571
Section 95.1: Get response body from a URL as a String......Page 573
Section 95.3: Delete resource......Page 574
Section 95.4: Check if resource exists......Page 575
Section 96.1: Basic Authentication......Page 577
Section 97.2: Intercept script output......Page 578
Section 97.5: Set global variables......Page 579
Section 97.7: Usage of Java objects in JavaScript in Nashorn......Page 580
Section 97.8: Implementing an interface from script......Page 581
Section 98.1: Calling C++ methods from Java......Page 582
Section 98.2: Calling Java methods from C++ (callback)......Page 583
Section 98.3: Loading native libraries......Page 585
Section 99.1: List of standard Java Runtime Library functional interfaces by signature......Page 587
Section 100.1: Fluent programming style......Page 589
Section 100.2: Truth - Fluent Testing Framework......Page 590
Section 101.1: Callback: invoking methods on a "client"......Page 591
Section 101.2: Simple RMI example with Client and Server implementation......Page 595
Section 101.3: Client-Server: invoking methods in one JVM from another......Page 597
Section 102.2: Creating your own Iterable......Page 600
Section 102.3: Using Iterable in for loop......Page 601
Section 102.4: Using the raw iterator......Page 602
Section 103.1: Dynamic Proxies......Page 603
Section 103.2: Introduction......Page 604
Section 103.3: Evil Java hacks with Reflection......Page 605
Section 103.4: Misuse of Reflection API to change private and final variables......Page 607
Section 103.5: Getting and Setting fields......Page 608
Section 103.6: Call constructor......Page 609
Section 103.8: Invoking a method......Page 610
Section 103.10: Getting the Constants of an Enumeration......Page 611
Section 103.11: Call overloaded constructors using reflection......Page 612
Section 104.2: Basic Usage - Creating a ByteBuer......Page 614
Section 104.3: Basic Usage - Write Data to the Buer......Page 615
Section 105.1: Minimal Applet......Page 616
Section 105.3: Open links from within the applet......Page 617
Section 105.4: Loading images, audio and other resources......Page 618
Section 106.1: Operator Precedence......Page 620
Section 106.2: Expression Basics......Page 621
Section 106.3: Expression evaluation order......Page 622
Section 106.4: Constant Expressions......Page 623
Section 107.1: Using Jackson Object Mapper......Page 625
Section 107.3: JSONObject.NULL......Page 626
Section 107.6: JSON Iteration......Page 627
Section 107.9: JsonArray to Java List (Gson Library)......Page 628
Section 107.11: Decoding JSON data......Page 629
Section 108.1: Parsing a document using the StAX API......Page 631
Section 108.2: Parsing and navigating a document using the DOM API......Page 632
Section 109.2: Parsing single XPath Expression multiple times in an XML......Page 634
Section 109.3: Evaluating a NodeList in an XML document......Page 635
Section 110.1: Reading a XML file......Page 636
Section 110.2: Writing to a XML File......Page 638
Section 111.1: Method Overriding......Page 641
Section 111.2: Method Overloading......Page 642
Section 111.3: Polymorphism and dierent types of overriding......Page 643
Section 111.4: Virtual functions......Page 646
Section 111.5: Adding behaviour by adding classes without touching existing code......Page 647
Section 112.1: Encapsulation to maintain invariants......Page 649
Section 112.2: Encapsulation to reduce coupling......Page 650
Section 113.2: Adding an agent at runtime......Page 651
Section 113.3: Setting up a basic agent......Page 652
Section 114.2: Specifying a varargs parameter......Page 653
Section 115.1: Logging complex messages (eciently)......Page 654
Section 115.2: Using the default logger......Page 655
Section 115.3: Logging levels......Page 656
Section 116.2: How to get Log4j......Page 658
Section 116.3: Setting up property file......Page 659
Section 116.5: How to use Log4j in Java code......Page 660
Section 116.6: Migrating from log4j 1.x to 2.x......Page 661
Section 116.7: Filter Logoutput by level (log4j 1.x)......Page 662
Section 117.1: Naming Conventions......Page 663
Section 117.2: Class Structure......Page 664
Section 117.4: Import statements......Page 665
Section 117.5: Braces......Page 666
Section 117.7: Modifiers......Page 667
Section 117.11: Lambda Expressions......Page 668
Section 117.13: Wrapping statements......Page 669
Section 117.15: Wrapping Expressions......Page 670
Section 117.17: Special Characters......Page 671
Section 117.18: Variable Declarations......Page 672
Section 118.2: Writing text to a file in UTF-8......Page 673
Section 118.3: Getting byte representation of a string in UTF-8......Page 674
Section 119.2: Implement hashCode() method......Page 675
Section 119.3: Implement toString() method......Page 676
Section 120.1: Locale......Page 678
Section 120.3: String Comparison......Page 679
Section 121.1: Fork/Join Tasks in Java......Page 680
Section 122.1: final......Page 682
Section 122.2: static......Page 683
Section 122.3: abstract......Page 684
Section 122.5: volatile......Page 685
Section 122.6: synchronized......Page 686
Section 122.7: transient......Page 687
Section 123.1: Pitfall: Runtime.exec, Process and ProcessBuilder don't understand shell syntax......Page 688
Section 123.2: Simple example (Java version < 1.5)......Page 690
Section 124.1: Introduction to JNA......Page 691
Section 125.1: Defining a basic module......Page 692
Section 126.1: Callable and Future......Page 693
Section 126.2: CountDownLatch......Page 694
Section 126.3: Basic Multithreading......Page 696
Section 126.4: Locks as Synchronisation aids......Page 697
Section 126.5: Semaphore......Page 698
Section 126.6: Synchronization......Page 699
Section 126.7: Runnable Object......Page 700
Section 126.8: Creating basic deadlocked system......Page 701
Section 126.9: Creating a java.lang.Thread instance......Page 703
Section 126.10: Atomic operations......Page 704
Section 126.11: Exclusive write / Concurrent read access......Page 705
Section 126.12: Producer-Consumer......Page 706
Section 126.13: Visualizing read/write barriers while using synchronized / volatile......Page 708
Section 126.14: Get status of all threads started by your program excluding system threads......Page 709
Section 126.15: Using ThreadLocal......Page 710
Section 126.16: Multiple producer/consumer example with shared global queue......Page 711
Section 126.17: Add two `int` arrays using a Threadpool......Page 712
Section 126.18: Pausing Execution......Page 713
Section 126.19: Thread Interruption / Stopping Threads......Page 714
Section 127.1: ThreadPoolExecutor......Page 717
Section 127.2: Retrieving value from computation - Callable......Page 718
Section 127.3: submit() vs execute() exception handling dierences......Page 719
Section 127.5: Fire and Forget - Runnable Tasks......Page 721
Section 127.6: Use cases for dierent types of concurrency constructs......Page 722
Section 127.7: Wait for completion of all tasks in ExecutorService......Page 723
Section 127.8: Use cases for dierent types of ExecutorService......Page 725
Section 127.9: Scheduling tasks to run at a fixed time, after a delay or repeatedly......Page 727
Section 127.10: Using Thread Pools......Page 728
Section 128.1: Basic ThreadLocal usage......Page 729
Section 128.2: ThreadLocal Java 8 functional initialization......Page 730
Section 128.3: Multiple threads with one shared object......Page 731
Section 129.1: Performing Asynchronous Tasks Where No Return Value Is Needed Using a Runnable Class Instance......Page 733
Section 129.2: Performing Asynchronous Tasks Where a Return Value Is Needed Using a Callable Class Instance......Page 734
Section 129.3: Defining Asynchronous Tasks Inline using Lambdas......Page 737
Section 130.2: Pitfall: using == to compare strings......Page 739
Section 130.3: Pitfall: forgetting to free resources......Page 741
Section 130.4: Pitfall: testing a file before attempting to open it......Page 742
Section 130.5: Pitfall: thinking of variables as objects......Page 743
Section 130.6: Pitfall: memory leaks......Page 746
Section 130.7: Pitfall: Not understanding that String is an immutable class......Page 747
Section 130.8: Pitfall: combining assignment and side-eects......Page 748
Section 131.1: Pitfall - Catching Throwable, Exception, Error or RuntimeException......Page 749
Section 131.2: Pitfall - Ignoring or squashing exceptions......Page 750
Section 131.3: Pitfall - Throwing Throwable, Exception, Error or RuntimeException......Page 751
Section 131.4: Pitfall - Using exceptions for normal flowcontrol......Page 752
Section 131.6: Pitfall - Catching InterruptedException......Page 753
Section 131.7: Pitfall - Excessive or inappropriate stacktraces......Page 755
Section 132.2: Pitfall - Declaring classes with the same names as standard classes......Page 756
Section 132.3: Pitfall - Leaving out braces: the "dangling if" and "dangling else" problems......Page 757
Section 132.5: Pitfall - Using '==' to test a boolean......Page 759
Section 132.7: Pitfall: Using 'assert' for argument or user input validation......Page 760
Section 132.8: Pitfall - Wildcard imports can make your code fragile......Page 761
Section 132.9: Pitfall - Misplaced semicolons and missing braces......Page 762
Section 132.10: Pitfall - Overloading instead of overriding......Page 763
Section 132.11: Pitfall of Auto-Unboxing Null Objects into Primitives......Page 764
Section 133.1: Pitfall - Extending 'java.lang.Thread'......Page 765
Section 133.2: Pitfall - Too many threads makes an application slower......Page 766
Section 133.4: Pitfall: Shared variables require proper synchronization......Page 767
Section 133.5: Pitfall - Thread creation is relatively expensive......Page 770
Section 134.1: Pitfall - "Making good" unexpected nulls......Page 773
Section 134.2: Pitfall - Using null to represent an empty array or collection......Page 774
Section 134.4: Pitfall - Returning null instead of throwing an exception......Page 775
Section 134.5: Pitfall - Unnecessary use of Primitive Wrappers can lead to NullPointerExceptions......Page 776
Section 134.6: Pitfall - Using "Yoda notation" to avoid NullPointerException......Page 777
Section 135.1: Pitfall - String concatenation in a loop does not scale......Page 778
Section 135.3: Pitfall - Interning strings so that you can use == is a bad idea......Page 779
Section 135.5: Pitfall - Eciency concerns with regular expressions......Page 781
Section 135.6: Pitfall - Small reads / writes on unbuered streams are inecient......Page 784
Section 135.7: Pitfall - Over-use of primitive wrapper types is inecient......Page 786
Section 135.8: Pitfall - The overheads of creating log messages......Page 787
Section 135.10: Pitfall - Calling System.gc() is inecient......Page 788
Section 135.11: Pitfall - Calling 'new String(String)' is inecient......Page 789
Section 136.1: Simple ServiceLoader Example......Page 790
Section 136.2: Logger Service......Page 791
Section 137.2: Loading an external .class file......Page 793
Section 137.3: Instantiating and using a classloader......Page 794
Section 138.1: Creating a simple image programmatically and displaying it......Page 796
Section 138.3: Setting individual pixel's color in BueredImage......Page 797
Section 138.4: Specifying image rendering quality......Page 798
Section 138.5: Creating an image with BueredImage class......Page 800
Section 138.6: Editing and re-using image with BueredImage......Page 801
Section 138.7: How to scale a BueredImage......Page 802
Section 139.2: Motivation for Atomic Types......Page 803
Section 140.1: An example using a hybrid cryptosystem consisting of OAEP and GCM......Page 807
Section 141.2: SignedObject (java.security.SignedObject)......Page 812
Section 142.2: Encrypt and Decrypt Data with Public / Private Keys......Page 814
Section 142.4: Generate Public / Private Key Pairs......Page 815
Section 142.5: Compute and Verify Digital Signatures......Page 816
Section 143.6: Hashing and Validation......Page 817
Section 144.1: Sandboxing classes loaded by a ClassLoader......Page 819
Section 144.3: Implementing policy deny rules......Page 820
Section 145.1: RMI through JNDI......Page 828
Section 146.3: Getting Instance of Unsafe......Page 832
Section 146.4: Uses of Unsafe......Page 833
Section 147.1: Motivation for the Memory Model......Page 834
Section 147.2: Happens-before relationships......Page 836
Section 147.3: How to avoid needing to understand the Memory Model......Page 837
Section 147.4: Happens-before reasoning applied to some examples......Page 838
Section 148.1: Making an executable JAR from the command line......Page 841
Section 148.2: Creating an UberJAR for an application and its dependencies......Page 842
Section 148.3: Creating JAR, WAR and EAR files......Page 843
Section 148.4: Introduction to Java Web Start......Page 844
Section 149.1: Using URLClassLoader......Page 847
Section 150.1: Basic Java Bean......Page 851
Section 151.3: The try-with-resources statement......Page 852
Section 151.6: Strings in switch Statements......Page 853
Section 152.1: New Java SE 8 programming language features......Page 855
Section 153.1: Dynamic Method Dispatch - Example Code......Page 856
Section 154.1: Generate POJO From JSON......Page 859
Section 155.1: Editting Snippets......Page 860
Section 155.3: Expressions......Page 861
Section 155.5: Variables......Page 862
Section 156.1: Print all stack frames of the current thread......Page 863
Section 156.3: Showing reflection and other hidden frames......Page 864
Section 157.1: Read from socket......Page 866
Section 158.1: A simple TCP echo back server......Page 867
Section 159.1: Connecting and Logging Into a FTP Server......Page 870
Section 160.1: Evaluating A JavaScript file in -scripting mode of nashorn......Page 875
Section 161.2: Classes Defined within Other Constructs......Page 878
Section 161.3: Pass-by-value & Pass-by-reference......Page 880
Section 161.6: Abstract Methods & Classes......Page 881
Section 162.1: Play a MIDI file......Page 883
Section 162.3: Basic audio output......Page 884
Section 162.4: Bare metal sound......Page 885
Section 163.2: Discovering the available print services......Page 887
Section 163.4: Listening print job request status change......Page 888
Section 163.6: Creating a print job from a print service......Page 890
Section 164.1: Simple Example of CompletableFuture......Page 892
Section 165.1: Adding shutdown hooks......Page 893
Section 166.1: What is Unit Testing?......Page 894
Section 167.1: Checking arithmetic with assert......Page 897
Section 168.2: Creating a multi-release Jar using the jar tool......Page 898
Section 168.3: URL of a loaded class inside a multi-release Jar......Page 899
Section 169.1: Overview......Page 901
Section 170.1: What is Bytecode?......Page 903
Section 170.2: How to edit jar files with ASM......Page 904
Section 170.3: How to load a ClassNode as a Class......Page 906
Section 170.5: Javassist Basic......Page 907
Section 171.1: Viewing bytecode with javap......Page 909
Section 172.1: Simple example with Platform MBean Server......Page 916
Section 173.1: These are the basics......Page 920
Section 174.1: Generating Java code from simple XSD file......Page 921
Section 175.4: -XXcallProfiling......Page 924
Section 175.7: -XXdumpSize......Page 925
Section 175.8: -XXexitOnOutOfMemory......Page 926
Section 176.1: Iterate over objects reachable from object (Heap 1.0)......Page 927
Section 176.3: Example of initialization inside of Agent_OnLoad method......Page 929
Section 177.1: Setting the Heap, PermGen and Stack sizes......Page 931
Section 177.2: Garbage collection......Page 932
Section 177.3: Memory leaks in Java......Page 934
Section 177.4: Finalization......Page 935
Section 177.5: Manually triggering GC......Page 936
Section 178.1: An evidence-based approach to Java performance tuning......Page 937
Section 178.3: General approach......Page 938
Section 179.1: Simple JMH example......Page 940
Section 180.1: Upload file to s3 bucket......Page 943
Section 181.1: Example of Instrumentation of all BW Applications in a Single Step for Appdynamics......Page 945
Section A.1: Setting %PATH% and %JAVA_HOME% after installing on Windows......Page 946
Section A.2: Installing a Java JDK on Linux......Page 947
Section A.3: Installing a Java JDK on macOS......Page 949
Section A.4: Installing a Java JDK or JRE on Windows......Page 950
Section A.5: Configuring and switching Java versions on Linux using alternatives......Page 951
Section A.7: Selecting an appropriate Java SE release......Page 952
Section A.9: Installing Oracle Java on Linux with latest tar file......Page 953
Section A.10: Post-installation checking and configuration on Linux......Page 954
Section B.1: Dierences between Java SE JRE or Java SE JDK distributions......Page 957
Section B.2: Java SE Versions......Page 958
Section B.3: Dierences between Java EE, Java SE, Java ME and JavaFX......Page 959
Section C.2: Adding all JARs in a directory to the classpath......Page 961
Section C.4: Classpath path syntax......Page 962
Section C.7: The bootstrap classpath......Page 963
Section C.8: What the classpath means: how searches work......Page 964
Section D.3: Finding and reading resources using a classloader......Page 965
Section D.4: Loading same-name resource from multiple JARs......Page 967
Credits......Page 968
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