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Refactoring to Java 8 (Devoxx UK)
The document discusses the benefits and considerations of refactoring to Java 8, emphasizing performance improvements and the use of lambda expressions. It highlights the balance between automated and manual refactoring, stressing that while new features can simplify code, they may not always enhance performance. Ultimately, the decision to migrate to Java 8 should be based on specific goals and thorough performance evaluation.
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Refactoring to Java 8 (Devoxx UK)
- 1. @trisha_gee#DevoxxUK Refactoring to Java8 Trisha Gee, JetBrains @trisha_gee trishagee.com
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- 3. It’s Faster •Performance Improvementsin Common Data Structures •Fork/Join Speed Improvements •Changes to Support Concurrency •…and more http://bit.ly/refJ8
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- 5. Fewer lines ofcode
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- 10. Decide on theGoals
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- 19. Automatic Refactoring •For loopto collect •For loop to forEach •…with and without Streams
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- 23. But what aboutperformance?
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- 25. 0 20 40 60 80 100 120 140 160 180 Ops/ms Lambdas vsAnonymous Inner Classes Anonymous Inner Class Lambda
- 26. http://www.oracle.com/technetwork/java/jvmls2013kuksen-2014088.pdf 0 2 4 6 8 10 12 14 16 18 20 single thread maxthreads nsec/op Performance of Capture anonymous(static) anonymous(non-static) lambda
- 27. 0 50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000 500,000 Constant message Variablemessage Ops/ms Logging Performance Lambda Direct call
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- 29. 0 1 2 3 4 5 6 7 8 9 Ops/ms Iterator vsStream for loop forEach()
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- 34. 0 50,000 100,000 150,000 200,000 250,000 300,000 350,000 Value not nullValue null Ops/ms Compare Constant Field Value with Null Null check Optional
- 35. 0 50,000 100,000 150,000 200,000 250,000 300,000 Value not nullValue null Ops/ms Compare Variable Field Value with Null Null check Optional
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- 37. Sometimes new idiomsdecrease clutter
- 39. …but sometimes theydon’t
- 41. Sometimes the newfeatures improve performance
- 42. 0 20 40 60 80 100 120 140 160 180 Ops/ms Lambdas vsAnonymous Inner Classes Anonymous Inner Class Lambda
- 43. …and sometimes theydon’t
- 44. 0 50,000 100,000 150,000 200,000 250,000 300,000 Value not nullValue null Ops/ms Compare Variable Field Value with Null Null check Optional
- 45. Sometimes a newfeature makes life easier
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- 49. Some refactoring cansafely be done automatically
- 51. …often you needa human brain
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- 54. Should you migrateyour code to Java 8?
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- 56. Always remember whatyour goal is And compare results to it
- 57. Understand what mayimpact performance And if in doubt, measure
- 58. Code may magicallyimprove Or you may expose areas for improvement
- 59. Your tools canhelp you But you need to apply your brain too
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