Convert Shaded Java class to its original

Casting the shaded class to its original is not possible, even though they are exactly similar. One will hit classCastExceptions while doing so

The simplest and easiest way is to serialize the shaded class is, using a serializer that doesn't encode the original class information in the serialized version and the deserialize it back. The default Java serializer cannot be used for this. However, gson is a good option.

import shade.prefix.com.company.Employee;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class ShadedEmployeeToVanillaEmployeeConverter {
  private static final Gson gson = createGson();
  private static final String packagePrefix = "shade.prefix.";
  
  public <U extends com.company.Employee> U convert(Employee shadedType) {
    String json = gson.toJson(shadedType);
    try {
      Class<?> clazz = Class.forName(shadedType.getClass().getTypeName().replaceAll(packagePrefix, ""));
      Object o = gson.fromJson(json, clazz);
      return (U) o;
    } catch (ClassNotFoundException e) {
      throw new RuntimeException(e);
    }
  }

  private static Gson createGson() {
    GsonBuilder builder = new GsonBuilder();
    return builder.create();
  }
}

Limitations: (Pointed out by @derek elkins)

This approach will only work for "value" objects, and even then it will have caveats, e.g. loss of numerical precision and the inability to handle objects with cyclic reference graphs. For example, this clearly won't work for a "service" object that holds, say, an open network connection.

posted 11 days ago

CC BY-SA 4.0

11d ago

Abbas Gadhia‭

89 reputation 5 4 11 5