Evolving with Java - How to remain Relevant and Effective
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Slides from my GIDS 2019 presentation - Evolving with Java - How to remain relevant and effective. In this presentation, I share examples of evolving with Java to overcome the pain points.
![public static void main(String[] args) {
List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6);
List<Integer> result = numbers.stream()
.map(ParallelStreams::computeHeavyArithmetic)
.collect(Collectors.toList());
System.out.println(result);
}
public static void main(String[] args) {
List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6);
List<Integer> result = numbers.parallelStream()
.map(ParallelStreams::computeHeavyArithmetic)
.collect(Collectors.toList());
System.out.println(result);
}](https://image.slidesharecdn.com/gids2019evolvingwithjavaslideshare-190423170327/85/Evolving-with-Java-How-to-remain-Relevant-and-Effective-18-320.jpg)
![public static void main(String[] args) {
List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6);
List<Integer> result = numbers.stream()
.map(ParallelStreams::computeHeavyArithmetic)
.collect(Collectors.toList());
System.out.println(result);
}
public static void main(String[] args) {
List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6);
List<Integer> result = numbers.parallelStream()
.map(ParallelStreams::computeHeavyArithmetic)
.collect(Collectors.toList());
System.out.println(result);
}](https://image.slidesharecdn.com/gids2019evolvingwithjavaslideshare-190423170327/85/Evolving-with-Java-How-to-remain-Relevant-and-Effective-19-320.jpg)
![public static String concatWithPlus(String[]
values) {
String result = "";
for (int i = 0; i < values.length; i++) {
result += values[i];
}
return result;
}](https://image.slidesharecdn.com/gids2019evolvingwithjavaslideshare-190423170327/85/Evolving-with-Java-How-to-remain-Relevant-and-Effective-27-320.jpg)
![public static String
concatWithStringBuffer(String[] values) {
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < values.length; i++) {
buffer.append(values[i]);
}
return buffer.toString();
}](https://image.slidesharecdn.com/gids2019evolvingwithjavaslideshare-190423170327/85/Evolving-with-Java-How-to-remain-Relevant-and-Effective-28-320.jpg)
![public static void main(String[] args) {
List numbers = Arrays.asList(1, 2, 3, 4, 5);
Iterator iterator = numbers.iterator();
while (iterator.hasNext()) {
Number number =
(Number) iterator.next();
System.out.println(number);
}
}
Java 1.4](https://image.slidesharecdn.com/gids2019evolvingwithjavaslideshare-190423170327/85/Evolving-with-Java-How-to-remain-Relevant-and-Effective-41-320.jpg)
![public static void main(String[] args) {
List numbers = Arrays.asList(1, 2, 3, 4, 5);
Iterator iterator = numbers.iterator();
while (iterator.hasNext()) {
Number number =
(Number) iterator.next();
System.out.println(number);
}
} List<Number> numbers =
Arrays.asList(1, 2, 3, 4, 5);
for(Number number : numbers) {
System.out.println(number);
}
Java 1.4
Java 5](https://image.slidesharecdn.com/gids2019evolvingwithjavaslideshare-190423170327/85/Evolving-with-Java-How-to-remain-Relevant-and-Effective-42-320.jpg)
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Evolving with Java - How to remain Relevant and Effective
- 1. Evolving with Java - How to Remain Relevant & Effective Naresha K, Technical Excellence Coach | Consultant | Agile & Cloud Transformation Catalyst @naresha_k https://blog.nareshak.com/
- 4. Business
- 5. Time to Market | Speed of Delivery
- 6. Economy
- 8. About Me
- 15. Relevant?
- 17. Effective?
- 18. public static void main(String[] args) { List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); List<Integer> result = numbers.stream() .map(ParallelStreams::computeHeavyArithmetic) .collect(Collectors.toList()); System.out.println(result); } public static void main(String[] args) { List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); List<Integer> result = numbers.parallelStream() .map(ParallelStreams::computeHeavyArithmetic) .collect(Collectors.toList()); System.out.println(result); }
- 19. public static void main(String[] args) { List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); List<Integer> result = numbers.stream() .map(ParallelStreams::computeHeavyArithmetic) .collect(Collectors.toList()); System.out.println(result); } public static void main(String[] args) { List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); List<Integer> result = numbers.parallelStream() .map(ParallelStreams::computeHeavyArithmetic) .collect(Collectors.toList()); System.out.println(result); }
- 21. private static Logger LOGGER = LoggerFactory .getLogger(MyClass.class);
- 23. All models are wrong, but some are useful. George Box https://en.wikipedia.org/wiki/All_models_are_wrong
- 24. Pain!
- 25. Suffering Pain!
- 26. Pain is the hammer of the gods to break A dead resistance in the mortal’s heart https://dhavaldalal.wordpress.com/2006/08/02/pain-and-suffering/
- 27. public static String concatWithPlus(String[] values) { String result = ""; for (int i = 0; i < values.length; i++) { result += values[i]; } return result; }
- 28. public static String concatWithStringBuffer(String[] values) { StringBuffer buffer = new StringBuffer(); for (int i = 0; i < values.length; i++) { buffer.append(values[i]); } return buffer.toString(); }
- 29. Java 1.4
- 30. Java 5
- 32. Maintainability?
- 33. ‘+’ vs StringBuffer Level of Abstraction API Contract Concatenation Concatenation Thread Safety
- 34. Favour higher level of abstraction
- 35. Premature optimisation is the root of all evil ~ Donald Knuth
- 36. Rule 1: Don’t Rule 2: Don’t, yet Rule 3: Profile before optimising http://wiki.c2.com/?RulesOfOptimization
- 38. Make it work Make it Right Make it Fast http://wiki.c2.com/?MakeItWorkMakeItRightMakeItFast
- 40. Java 11
- 41. public static void main(String[] args) { List numbers = Arrays.asList(1, 2, 3, 4, 5); Iterator iterator = numbers.iterator(); while (iterator.hasNext()) { Number number = (Number) iterator.next(); System.out.println(number); } } Java 1.4
- 42. public static void main(String[] args) { List numbers = Arrays.asList(1, 2, 3, 4, 5); Iterator iterator = numbers.iterator(); while (iterator.hasNext()) { Number number = (Number) iterator.next(); System.out.println(number); } } List<Number> numbers = Arrays.asList(1, 2, 3, 4, 5); for(Number number : numbers) { System.out.println(number); } Java 1.4 Java 5
- 43. Syntactic Sugar
- 44. Minimise Moving Parts Imperative -> Declarative
- 45. Fail fast Runtime -> Compile time
- 46. /** * * @param customer * @return This method returns orders * of customer */ public List getOrdersOfCustomer(Customer customer);
- 47. /** * This method returns orders of customer * @param customer Customer whose orders to be fetched * @return List containing Order objects of the * specified Customer */ public List getOrdersOfCustomer(Customer customer);
- 48. public List<Order> getOrdersOfCustomer(Customer customer); public List<OrderSummary> getOrdersOfCustomer(Customer customer);
- 50. DRY Principle
- 51. List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); int sumOfSquaresOfEvenNumbers = 0; for (Integer number : numbers) { if(number % 2 == 0) { sumOfSquaresOfEvenNumbers += number * number; } } System.out.println(sumOfSquaresOfEvenNumbers);
- 52. List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); int sumOfSquaresOfEvenNumbers = 0; for (Integer number : numbers) { if(number % 2 == 0) { sumOfSquaresOfEvenNumbers += number * number; } } System.out.println(sumOfSquaresOfEvenNumbers); Predicate<Integer> isEven = (number) -> number % 2 == 0; Function<Integer, Integer> square = (number) -> number * number; List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); Integer sum = numbers.stream() .filter(isEven) .map(square) .collect(Collectors. summingInt(Integer::intValue)); System.out.println(sum); Java 8
- 53. Declarative Code
- 54. Smaller Units
- 56. Easy to Modify
- 57. Are you confident enough to refactor? Tests give courage
- 58. Predicate<Integer> isEven = (number) -> number % 2 == 0; Function<Integer, Integer> square = (number) -> number * number; List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); Integer result = numbers.stream() .filter(isEven) .map(square) .findFirst().orElse(-1); System.out.println(result); Java 8
- 59. Predicate<Integer> isEven = (number) -> number % 2 == 0; Function<Integer, Integer> square = (number) -> number * number; List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); Integer result = numbers.stream() .filter(isEven) .map(square) .findFirst().orElse(-1); System.out.println(result); List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6); int suqareOfFirstEvenNumber = -1; for (Integer number : numbers) { if(number % 2 == 0) { suqareOfFirstEvenNumber += number * number; break; } } System.out.println(suqareOfFirstEvenNumber); Java 8
- 60. What you see is not what you get
- 61. Lazy Evaluation
- 62. Understand one level below the abstraction you deal with
- 63. Food pizza = new Pizza(); Person friend = new Person("Ravi"); friend.getMouth().setFood(pizza);
- 64. Food pizza = new Pizza(); Person friend = new Person("Ravi"); friend.getMouth().setFood(pizza); Person friend = new Person("Ravi"); Edible food = new Pizza(); friend.offer(food);
- 65. Encapsulation
- 66. public static String readTemplate(String path) { Path templatePath = Paths.get(path); BufferedReader bufferedReader = Files.newBufferedReader(templatePath); // read from bufferedReader return ""; }
- 67. public static String readTemplate(String path) { Path templatePath = Paths.get(path); try { BufferedReader bufferedReader = Files.newBufferedReader(templatePath); } catch (IOException e) { e.printStackTrace(); } // read from bufferedReader return ""; }
- 71. Most people talk about Java the language, and this may sound odd coming from me, but I could hardly care less. At the core of the Java ecosystem is the JVM. - James Gosling, Creator of the Java Programming Language(2011, TheServerSide)
- 81. package com.nareshak.demo data class Person(val firstName: String, val lastName: String)
- 82. package com.nareshak.demo; import lombok.Getter; import lombok.Setter; @Getter @Setter public class Person { private String firstName; private String lastName; }
- 83. package com.nareshak.demo; import lombok.Getter; import lombok.Setter; @Getter @Setter public class Person { private String firstName; private String lastName; }
- 84. package com.nareshak.demo; import lombok.Data; @Data public class Person { private String firstName; private String lastName; }
- 87. Feel the pain and act upon it
- 88. I have not experienced the pain, yet.
- 90. JPMS - Java Modules
- 93. Thank You