Created
February 5, 2015 11:09
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Is reflection really that slow?
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import java.lang.reflect.InvocationTargetException; | |
import java.lang.reflect.Method; | |
public class TestReflection { | |
public static long INC = 0; | |
public static final int COUNT = 100000000; | |
private static class Dummy { | |
public void doSomething(String s1, String s2, String s3) { | |
INC++; | |
} | |
} | |
public static void main(String[] args) throws NoSuchMethodException { | |
Dummy obj = new Dummy(); | |
Method method = obj.getClass().getMethod("doSomething", String.class, String.class, String.class); | |
String s1 = "string1"; | |
String s2 = "string2"; | |
String s3 = "string3"; | |
//warmup | |
runReflection(obj, method, s1, s2, s3, COUNT / 10); | |
runStatic(obj, s1, s2, s3, COUNT/10); | |
///realtest | |
long reftime = System.nanoTime(); | |
runReflection(obj, method, s1, s2, s3, COUNT); | |
reftime = System.nanoTime() - reftime; | |
long time = System.nanoTime(); | |
runStatic(obj, s1, s2, s3, COUNT); | |
time = System.nanoTime() - time; | |
System.out.println(reftime); | |
System.out.println(time); | |
//1000 *1000 *1000 nanoseconds in a second | |
System.out.println(reftime / (1000 *1000 *1000)); | |
System.out.println(time / (1000 *1000 *1000)); | |
System.out.println((double)reftime/ (double)time ); | |
System.out.println("percentage speed decrease from using reflection:"+(((double)reftime/(double)time)-1)*100); | |
} | |
private static void runReflection(Dummy obj, Method method, String s1, String s2, String s3, int count) { | |
for (int i = 0; i < count; i++) { | |
try { | |
method.invoke(obj, s1, s2, s3); | |
} catch (IllegalArgumentException e) { | |
} catch (IllegalAccessException e) { | |
} catch (InvocationTargetException e) { | |
} | |
} | |
} | |
private static void runStatic(Dummy obj, String s1, String s2, String s3, int count) { | |
for (int i = 0; i < count; i++) { | |
obj.doSomething(s1,s2,s3); | |
} | |
} | |
} |
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