Why are interface method invocations slower than concrete invocations?

by

There are many performance myths, and some were probably true several years ago, and some might still be true on VMs that don’t have a JIT.

The Android documentation (remember that Android don’t have a JVM, they have Dalvik VM) used to say that invoking a method on an interfaces was slower than invoking it on a class, so they were contributing to spreading the myth (it’s also possible that it was slower on the Dalvik VM before they turned on the JIT). The documentation does now say:

Performance Myths

Previous versions of this document made various misleading claims. We
address some of them here.

On devices without a JIT, it is true that invoking methods via a
variable with an exact type rather than an interface is slightly more
efficient. (So, for example, it was cheaper to invoke methods on a
HashMap map than a Map map, even though in both cases the map was a
HashMap.) It was not the case that this was 2x slower; the actual
difference was more like 6% slower. Furthermore, the JIT makes the two
effectively indistinguishable.

Source: Designing for performance on Android

The same thing is probably true for the JIT in the JVM, it would be very odd otherwise.

More Related Contents:

  1. Should methods that throw RuntimeException indicate it in method signature?
  2. how do I get file size of temp file in android?
  3. Error: Could not find com.google.gms:google-services:1.0. when adding google service plugin in build.gradle in android studio
  4. add an element to int [] array in java [duplicate]
  5. How to create my own java library(API)?
  6. Theoretical limit for number of keys (objects) that can be stored in a HashMap?
  7. Can there exist two main methods in a Java program?
  8. Is it good to set the max and min JVM heap size the same?
  9. Firebase Authentication FirebaseNetworkException: A network error (such as timeout, interrupted connection or unreachable host) has occurred
  10. Error:resource android:style/TextAppearance.Material.Widget.Button.Borderless.Colored not found
  11. Marshalling LocalDate using JAXB
  12. JUnit 4 @BeforeClass & @AfterClass when using Suites
  13. How can I measure time with microsecond precision in Java?
  14. Finding prime numbers with the Sieve of Eratosthenes (Originally: Is there a better way to prepare this array?)
  15. Which real-time (RTSJ) JVM is most preferred? [closed]
  16. “Fix” String encoding in Java
  17. org.hibernate.loader.MultipleBagFetchException: cannot simultaneously fetch multiple bags
  18. How to URL encode a URL in JSP / JSTL?
  19. Java: For-Each loop and references [duplicate]
  20. how to programatically theme an activity to be like a dialog?
  21. How do I create an XPath function in Groovy
  22. If-else working, switch not [duplicate]
  23. How to set a custom object in a JTable row
  24. Problem with Json plugin in Struts 2
  25. Generate Subject Hash of X509Certificate in Java
  26. myLocationOverlay change the marker
  27. Concurrent read/write of named pipe in Java (on windows)
  28. Recyclerview not call any Adapter method :onCreateViewHolder,onBindViewHolder,
  29. Where do resource files go in a Gradle project that builds a Java 9 module?
  30. Replace HTML codes with equivalent characters in Java [duplicate]

Leave a Comment