Which library implementation to use/work on?

Sun Apr 8 13:18:00 GMT 2012

Thanks, I got it to work eventually. That switch disables building of
ecj so I had to first compile without it, then install, then adjust my
path, then reconfigure/make/make install - bit confusing.
I then encountered a couple of other issues. Firstly it seems there's
something odd about the Google protocol buffers library that gcj does
not like:
com/google/protobuf/SingleFieldBuilder.java: In method
'com.google.protobuf.SingleFieldBuilder.mergeFrom(com.google.protobuf.GeneratedMessage)':
com/google/protobuf/SingleFieldBuilder.java:192:0: error: class
'com.google.protobuf.GeneratedMessage' has no method named
'getDefaultInstanceForType' matching signature
'()Lcom/google/protobuf/Message;'
The code is some morass of generics so it's hard for me to figure out
what the issue is here. The relevant code is:
public class SingleFieldBuilder
 <MType extends GeneratedMessage,
 BType extends GeneratedMessage.Builder,
 IType extends MessageOrBuilder>
 implements GeneratedMessage.BuilderParent {
 ....
 private MType message;
 public SingleFieldBuilder<MType, BType, IType> mergeFrom(
 MType value) {
 if (builder == null && message == message.getDefaultInstanceForType()) {
 message = value;
 } else {
 getBuilder().mergeFrom(value);
 }
 onChanged();
 return this;
 }
}
Sure enough the GeneratedMessage class doesn't have
getDefaultInstanceForType - it's implemented by subclasses.
GeneratedMessage says this at the top:
/**
 * All generated protocol message classes extend this class. This class
 * implements most of the Message and Builder interfaces using Java reflection.
 * Users can ignore this class and pretend that generated messages implement
 * the Message interface directly.
 *
 * @author kenton@google.com Kenton Varda
 */
I suspect the reference to "implementing most of the interfaces using
reflection" is key. I don't know what that means exactly, the class is
very large and complicated:
http://code.google.com/p/protobuf/source/browse/trunk/java/src/main/java/com/google/protobuf/GeneratedMessage.java
I switched to the "lite" runtime which is simpler and the issue went away.
The next problem is more stubs in classpath: specifically the elliptic
curve related classes in java.security.spec. I'm already using
BouncyCastle to implement the EC crypto - these classes are literally
just data structures. They're probably quite trivial to do.
I'll try copying the equivalent code from openjdk and see if that works.