RandomPropertyOrderModule.java

import com.fasterxml.jackson.core.Version;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.Module;
import com.fasterxml.jackson.databind.SerializationConfig;
import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;
import com.fasterxml.jackson.databind.ser.BeanSerializerModifier;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Optional;

public class RandomPropertyOrderModule extends Module {

  @Override
  public String getModuleName() {
    return getClass().getSimpleName();
  }

  @Override
  public Version version() {
    return Version.unknownVersion();
  }

  @Override
  public void setupModule(SetupContext context) {
    context.addBeanSerializerModifier(new RandomPropertyOrderBeanSerializerModifier());
  }

  private static class RandomPropertyOrderBeanSerializerModifier
    extends BeanSerializerModifier {

    @Override
    public List<BeanPropertyWriter> orderProperties(
      SerializationConfig config,
      BeanDescription beanDesc,
      List<BeanPropertyWriter> beanProperties
    ) {
      if (shouldSortAlphabetically(config, beanDesc)) {
        return beanProperties;
      } else {
        beanProperties = new ArrayList<>(beanProperties);
        Collections.shuffle(beanProperties);

        return beanProperties;
      }
    }
  }

  private static boolean shouldSortAlphabetically(
    SerializationConfig config,
    BeanDescription beanDesc
  ) {
    Optional<Boolean> sortAlphabetically = Optional.ofNullable(
      config
        .getAnnotationIntrospector()
        .findSerializationSortAlphabetically(beanDesc.getClassInfo())
    );

    return sortAlphabetically.orElseGet(config::shouldSortPropertiesAlphabetically);
  }
}