https:\/\/builds.shipilev.net\/openjdk-jdk-valhalla\/<\/div><\/div>\n\n<\/a><\/p>\n\n\n\n
Wanted to compare the difference in memory \/ speed of using the value and primitive types. Here is simple test program I used.<\/p>\n\n\n\n
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As Regular Object (With Identity and Nullability)<\/strong><\/p>\n\n\n\npublic class Main {\n\n \/\/ Ensure you are using the valhalla jdk build\n \/\/ run with this command :\n \/\/ javac -XDenablePrimitiveClasses Main.java\n \/\/ then \n \/\/ java -XX:+EnablePrimitiveClasses Main\n\n static public class Point {\n private final double x ;\n private final double y ;\n\n public Point(double x, double y) {\n this.x = x;\n this.y = y;\n }\n }\n\n public static void main(String[] args) {\n\n long start = System.currentTimeMillis<\/em>();\n\n Point[] myArray = new Point[10_000_000];\n for (int i = 0; i < myArray.length; i++) {\n myArray[i]=new Point(2d,3d);\n }\n\n Runtime.getRuntime<\/em>().gc();\n\n printMemoryUsage<\/em>();\n\n System.out<\/em>.println(\"Array length : \"+myArray.length);\n\n System.out<\/em>.println(\"Total time \"+(System.currentTimeMillis<\/em>() - start)+ \" ms\");\n\n }\n\n private static void printMemoryUsage() {\n System.out<\/em>.println(\"MB: \" + (double) (Runtime.getRuntime<\/em>().totalMemory() - Runtime.getRuntime<\/em>().freeMemory()) \/ (1024*1024));\n }\n\n}<\/pre>\n\n\n\n<\/p>\n\n\n\n
If I run this above example (using regular java objects) these are the numbers I’m getting<\/p>\n\n\n\n
java Main.java<\/p>\n\n\n\n
MB: 346.2878112792969
Array length : 10000000
Total time 250 ms<\/em><\/p>\n\n\n\n<\/p>\n\n\n\n
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Now if we change the above Point class by making a primitive class (giving up Identity and Nullability) . To make it easy to do this, they have provided temporary keywords <\/p>\n\n\n\n
primitive <\/strong>to declare the class as primitive type (giving up identity and nullability)<\/p>\n\n\n\nvalue<\/strong> to declare the class as value type (giving up identity)<\/p>\n\n\n\n<\/p>\n\n\n\n
As Primitive Type<\/strong><\/p>\n\n\n\npublic class Main {\n\n \/\/ Ensure you are using the valhalla jdk build\n \/\/ run with this command :\n \/\/ javac -XDenablePrimitiveClasses Main.java\n \/\/ then \n \/\/ java -XX:+EnablePrimitiveClasses Main\n\n static public primitive class Point {\n private final double x ;\n private final double y ;\n\n public Point(double x, double y) {\n this.x = x;\n this.y = y;\n }\n }\n\n public static void main(String[] args) {\n\n long start = System.currentTimeMillis<\/em>();\n\n Point[] myArray = new Point[10_000_000];\n for (int i = 0; i < myArray.length; i++) {\n myArray[i]=new Point(2d,3d);\n }\n\n Runtime.getRuntime<\/em>().gc();\n\n printMemoryUsage<\/em>();\n\n System.out<\/em>.println(\"Array length : \"+myArray.length);\n\n System.out<\/em>.println(\"Total time \"+(System.currentTimeMillis<\/em>() - start)+ \" ms\");\n\n }\n\n private static void printMemoryUsage() {\n System.out<\/em>.println(\"MB: \" + (double) (Runtime.getRuntime<\/em>().totalMemory() - Runtime.getRuntime<\/em>().freeMemory()) \/ (1024*1024));\n }\n\n}<\/pre>\n\n\n\n<\/p>\n\n\n\n
This are the results if Point is primitive class<\/p>\n\n\n\n
java Main.java<\/p>\n\n\n\n
MB: 158.47823333740234
Array length : 10000000
Total time 72 ms<\/em><\/p>\n\n\n\n<\/p>\n\n\n\n
By turning the Point class into primitive class, it uses less than half the memory and it is 3x faster<\/p>\n\n\n\n
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As Value Type<\/strong> ( using “value” instead)<\/p>\n\n\n\nMB: 347.8201599121094
Array length : 10000000
Total time 224 ms<\/em><\/p>\n\n\n\n<\/p>\n\n\n\n
Declaring class as value type didn’t yield any memory saving, but did make code run slightly faster.<\/p>\n\n\n\n
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<\/p>\n","protected":false},"excerpt":{"rendered":"
The vallhalla project will hopefully bring lower cost objects (at the expense of giving up Object Identity and\/or nullability) Shipilev provides daily Valhalla builds, you can download from here : https:\/\/builds.shipilev.net\/openjdk-jdk-valhalla\/ Wanted to compare the difference in memory \/ speed of using the value and primitive types. Here is simple test program I used. As … <\/p>\n
Continue reading “Experimenting with Java Valhalla”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[3],"tags":[],"class_list":["post-833","post","type-post","status-publish","format-standard","hentry","category-java"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/833","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/comments?post=833"}],"version-history":[{"count":15,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/833\/revisions"}],"predecessor-version":[{"id":868,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/833\/revisions\/868"}],"wp:attachment":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/media?parent=833"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/categories?post=833"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/tags?post=833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}