Program: 11816
Project: 11816
Buggy source:
@Override public void handleReceived(ClientConnection connection){
  if (connection.getAddress().getHostString().equals("String_Node_Str")) {
    UUID id;
    try {
      URL url=new URL("String_Node_Str");
      HttpsURLConnection c=(HttpsURLConnection)url.openConnection();
      c.setRequestMethod("String_Node_Str");
      c.setRequestProperty("String_Node_Str","String_Node_Str");
      c.setRequestProperty("String_Node_Str","String_Node_Str");
      c.setDoOutput(true);
      c.setDoInput(true);
      c.getOutputStream().write(String.format("String_Node_Str",name()).getBytes());
      c.getOutputStream().close();
      int responseCode=c.getResponseCode();
      if (responseCode != 200) {
        connection.sendPacket(new PacketLoginOutDisconnect().setJsonMessage("String_Node_Str"));
        connection.logout();
        return;
      }
      StringBuilder sb=new StringBuilder();
      BufferedReader reader=new BufferedReader(new InputStreamReader(c.getInputStream()));
      String line;
      while ((line=reader.readLine()) != null) {
        sb.append(line);
        sb.append('\n');
      }
      reader.close();
      JsonArray array=PacketLoginInEncryptionResponse.GSON.fromJson(sb.toString(),JsonArray.class);
      id=UUID.fromString(PacketLoginInEncryptionResponse.idDash.matcher(array.getAsJsonArray().get(0).getAsJsonObject().get("String_Node_Str").getAsString()).replaceAll("String_Node_Str"));
    }
 catch (    Exception e) {
      TridentLogger.error(e);
      return;
    }
    PacketLoginOutSuccess success=new PacketLoginOutSuccess();
    success.uuid=id.toString();
    success.username=name();
    success.connection=connection;
    connection.enableCompression();
    connection.sendPacket(success);
    connection.setStage(Protocol.ClientStage.PLAY);
    TridentPlayer.spawnPlayer(connection,id);
    return;
  }
  LoginHandler.getInstance().initLogin(connection.getAddress(),this.name());
  PacketLoginOutEncryptionRequest p=new PacketLoginOutEncryptionRequest();
  connection.generateToken();
  p.set("String_Node_Str",connection.getVerificationToken());
  try {
    KeyPair pair=RSA.generate(1024);
    p.set("String_Node_Str",pair.getPublic().getEncoded());
    connection.setLoginKeyPair(pair);
  }
 catch (  NoSuchAlgorithmException ignored) {
  }
  connection.sendPacket(p);
}

Fixed version (ground truth):
@Override public void handleReceived(ClientConnection connection){
  if (connection.getAddress().getHostString().equals("String_Node_Str")) {
    UUID id;
    try {
      URL url=new URL("String_Node_Str");
      HttpsURLConnection c=(HttpsURLConnection)url.openConnection();
      c.setRequestMethod("String_Node_Str");
      c.setRequestProperty("String_Node_Str","String_Node_Str");
      c.setRequestProperty("String_Node_Str","String_Node_Str");
      c.setDoOutput(true);
      c.setDoInput(true);
      c.getOutputStream().write(String.format("String_Node_Str",name()).getBytes());
      c.getOutputStream().close();
      int responseCode=c.getResponseCode();
      if (responseCode != 200) {
        connection.sendPacket(new PacketLoginOutDisconnect().setJsonMessage("String_Node_Str"));
        connection.logout();
        return;
      }
      StringBuilder sb=new StringBuilder();
      BufferedReader reader=new BufferedReader(new InputStreamReader(c.getInputStream()));
      String line;
      while ((line=reader.readLine()) != null) {
        sb.append(line);
        sb.append('\n');
      }
      reader.close();
      JsonArray array=PacketLoginInEncryptionResponse.GSON.fromJson(sb.toString(),JsonArray.class);
      id=UUID.fromString(PacketLoginInEncryptionResponse.idDash.matcher(array.getAsJsonArray().get(0).getAsJsonObject().get("String_Node_Str").getAsString()).replaceAll("String_Node_Str"));
    }
 catch (    Exception e) {
      TridentLogger.error(e);
      return;
    }
    if (TridentServer.WORLD == null) {
      connection.sendPacket(new PacketLoginOutDisconnect().setJsonMessage("String_Node_Str"));
      TridentLogger.error("String_Node_Str");
      return;
    }
    PacketLoginOutSuccess success=new PacketLoginOutSuccess();
    success.uuid=id.toString();
    success.username=name();
    success.connection=connection;
    connection.enableCompression();
    connection.sendPacket(success);
    connection.setStage(Protocol.ClientStage.PLAY);
    TridentPlayer.spawnPlayer(connection,id);
    return;
  }
  LoginHandler.getInstance().initLogin(connection.getAddress(),this.name());
  PacketLoginOutEncryptionRequest p=new PacketLoginOutEncryptionRequest();
  connection.generateToken();
  p.set("String_Node_Str",connection.getVerificationToken());
  try {
    KeyPair pair=RSA.generate(1024);
    p.set("String_Node_Str",pair.getPublic().getEncoded());
    connection.setLoginKeyPair(pair);
  }
 catch (  NoSuchAlgorithmException ignored) {
  }
  connection.sendPacket(p);
}