[AVRO-2190] ReflectData...getSchema() produces bad output for abstract java classes

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.8.2
• Component/s: java

Environment

The working environment is Windows 10 with java 1.8 92 but I suspect this code will work on all systems.

• Assignee: Unassigned
• Reporter: Allan Wax
• Created: 21/Jun/18 02:05
• Updated: 17/Jul/23 12:30

Description

ReflectData produces 'invalid' type entries for Abstract objects.  An example is InetAddress.  What it produces is valid JSON but the schema cannot be used to deserialize/read the serialized/write output.  ReflectData produces is

{"type":"record","name":"InetAddress","namespace":"java.net","fields":[]}

but it should notice that InetAddress is an abstract class and go find the classes that extend the class.

{"type":"record","name":"Inet4Address","namespace":"java.net","fields":[]}

,{"type":"record","name":"Inet6Address","namespace":"java.net","fields":[]}

 

I have a current workaround for this with the following, but it is a little hacky and not that efficient if used alot.

private static String abstractInetAddress = "{\"type\":\"record\",\"name\":\"InetAddress\",\"namespace\":\"java.net\",\"fields\":[]}";

private static String abstractInetAddressReplacement = //
  "{\"type\":\"record\",\"name\":\"Inet4Address\",\"namespace\":\"java.net\",\"fields\":[]}" + //
  ",{\"type\":\"record\",\"name\":\"Inet6Address\",\"namespace\":\"java.net\",\"fields\":[]}";

public AvroUtil(Class<T> clazz) {
    schema = ReflectData.AllowNull.get().getSchema(clazz);
    String s = schema.toString().replace(abstractInetAddress, abstractInetAddressReplacement);
    schema = new Schema.Parser().parse(s);

    this.clazz = clazz;
}