Java optional field bug?

[Chengdu Huang]

I have a simple thrift file:

struct UserDataContent {
    1: i32 id,
    2: optional i32 value,
}

Java file generated by "thrift --gen java " doesn't seem to respect
the "optional" keyword:

  public void write(TProtocol oprot) throws TException {
    validate();

    oprot.writeStructBegin(STRUCT_DESC);
    oprot.writeFieldBegin(ID_FIELD_DESC);
    oprot.writeI32(this.id);
    oprot.writeFieldEnd();
    oprot.writeFieldBegin(VALUE_FIELD_DESC);
    oprot.writeI32(this.value);
    oprot.writeFieldEnd();
    oprot.writeFieldStop();
    oprot.writeStructEnd();
  }

However, java file generated using "thrift --gen java:beans" looks
correct to me:
 public void write(TProtocol oprot) throws TException {
    validate();

    oprot.writeStructBegin(STRUCT_DESC);
    oprot.writeFieldBegin(ID_FIELD_DESC);
    oprot.writeI32(this.id);
    oprot.writeFieldEnd();
    if (isSetValue()) {
      oprot.writeFieldBegin(VALUE_FIELD_DESC);
      oprot.writeI32(this.value);
      oprot.writeFieldEnd();
    }
    oprot.writeFieldStop();
    oprot.writeStructEnd();
  }

My question is that why "normal" java style files should be different
from "beans" style files in terms of handling optional fields?

The change is introduced in rev665308 (t_java_generator.cc:1105).

Thanks,
Chengdu