How to avoid GeneratedSerializationConstructorAccessor problems?

Question

We have a Java App that receives SOAP requests, and after a lot of requests we notice that the GC stops the world to unload a lot of GeneratedSerializationConstructorAccessor classes. This is a big performance impact.

Does anyone know how to avoid this or at least significantly reduce the count of GeneratedSerializationConstructorAccessor classes created?

Answer 1

Use one of the options:

-Dsun.reflect.inflationThreshold=30

Increases the number of calls through a Constructor/Method/Field before a native accessor will be "inflated" to a generated accessor. The default is 15.

-Dsun.reflect.inflationThreshold=0

Disables inflation altogether. Interestingly, this option does not seem to affect constructors, but it does work for methods.

You can test the options with a simple test app:

public class a {
  public static void main(String[] args) throws Exception {
    for (int i = 0; i < 20; i++) {
      a.class.getDeclaredConstructor(null).newInstance(null);
    }
  }

  private static int x;
  public a() {
    new Throwable("" + x++).printStackTrace();
  }
}

Edit (29-Dec-2013): The -Dsun.reflect.noInflation=true option disables the inflation mechanism and instead immediately uses generated accessors, so you don't want that option.

Answer 2

[...] we notice that the GC stops the world to unload a lot of GeneratedSerializationConstructorAccessor classes. This is a big performance impact.

As it is impossible to avoid if your application is using reflection, you may try using CMS garbage collector to minimize the impact of the stop-the-world GC.