Program: 38108
Project: 38108
Buggy source:
@Override public void handle(HttpExchange exchange){
  Debug.log("String_Node_Str" + exchange.getRequestMethod() + "String_Node_Str"+ exchange.getRequestURI().toString());
  String key=exchange.getRequestMethod() + "String_Node_Str" + exchange.getHttpContext().getPath();
  Class<? extends Command> commandClass=CommandClasses.get(key);
  Debug.log("String_Node_Str" + commandClass);
  String uuid=Authenticate.performAuthentication(exchange);
  if (uuid == null && !commandClass.equals(PostLoginCommand.class)) {
    Debug.log("String_Node_Str");
    respond(new ErrorResponse(HttpStatusCode.UNAUTHORIZED,"String_Node_Str"),exchange);
    return;
  }
 else   if (commandClass == null && !key.equals("String_Node_Str") && !key.equals("String_Node_Str") && !key.equals("String_Node_Str")) {
    Debug.log("String_Node_Str" + exchange.getRequestMethod() + "String_Node_Str"+ exchange.getRequestURI());
    respond(new ErrorResponse(HttpStatusCode.BAD_REQUEST,"String_Node_Str" + "String_Node_Str"),exchange);
    return;
  }
  try {
switch (key) {
case ("String_Node_Str"):
      downloadHandler.handleGET(exchange);
    return;
case ("String_Node_Str"):
  uploadHandler.handleGET(exchange);
return;
case ("String_Node_Str"):
uploadHandler.handlePOST(exchange);
return;
}
}
 catch (Exception e) {
Debug.log("String_Node_Str");
return;
}
String json=readBody(exchange);
if (json.isEmpty()) json="String_Node_Str";
Debug.log("String_Node_Str" + json);
Command command=null;
try {
command=gson.fromJson(json,commandClass);
}
 catch (Exception e) {
Debug.log("String_Node_Str");
respond(new ErrorResponse(HttpStatusCode.INTERNAL_SERVER_ERROR,"String_Node_Str"),exchange);
return;
}
Debug.log("String_Node_Str" + command);
HashMap<String,String> query=new HashMap<>();
String uri;
try {
uri=Util.parseURI(exchange.getRequestURI(),query);
}
 catch (Exception e) {
Debug.log("String_Node_Str");
respond(new ErrorResponse(HttpStatusCode.INTERNAL_SERVER_ERROR,"String_Node_Str"),exchange);
return;
}
if (command.getExpectedNumberOfURIFields() != calculateURILength(uri)) {
Debug.log("String_Node_Str" + exchange.getRequestMethod() + "String_Node_Str"+ exchange.getRequestURI());
Debug.log("String_Node_Str" + command.getExpectedNumberOfURIFields() + "String_Node_Str"+ calculateURILength(uri));
respond(new ErrorResponse(HttpStatusCode.BAD_REQUEST,"String_Node_Str" + "String_Node_Str"),exchange);
return;
}
UserType userType=UserType.UNKNOWN;
if (!commandClass.equals(PostLoginCommand.class)) {
try (DatabaseAccessor db=Command.initDB()){
userType=db.getRole(Authenticate.getUsernameByID(uuid));
}
 catch (SQLException|IOException e) {
Debug.log(e.toString());
ErrorResponse errorResponse=new ErrorResponse(HttpStatusCode.INTERNAL_SERVER_ERROR,"String_Node_Str" + "String_Node_Str");
respond(errorResponse,exchange);
}
}
command.setFields(uri,query,Authenticate.getUsernameByID(uuid),userType);
try {
command.validate();
}
 catch (ValidateException e) {
Debug.log(e.getMessage());
ErrorLogger.log("String_Node_Str",e.getMessage());
respond(new ErrorResponse(e.getCode(),e.getMessage()),exchange);
return;
}
if (commandClass.equals(ProcessCommands.class)) {
respond(new ProcessResponse(HttpStatusCode.NOT_IMPLEMENTED),exchange);
}
 else {
respond(command.execute(),exchange);
}
}

Fixed version (ground truth):
@Override public void handle(HttpExchange exchange){
  Debug.log("String_Node_Str" + exchange.getRequestMethod() + "String_Node_Str"+ exchange.getRequestURI().toString());
  String key=exchange.getRequestMethod() + "String_Node_Str" + exchange.getHttpContext().getPath();
  Class<? extends Command> commandClass=CommandClasses.get(key);
  Debug.log(commandClass.getName());
  String uuid=Authenticate.performAuthentication(exchange);
  if (uuid == null && !commandClass.equals(PostLoginCommand.class)) {
    Debug.log("String_Node_Str");
    respond(new ErrorResponse(HttpStatusCode.UNAUTHORIZED,"String_Node_Str"),exchange);
    return;
  }
 else   if (commandClass == null && !key.equals("String_Node_Str") && !key.equals("String_Node_Str") && !key.equals("String_Node_Str")) {
    Debug.log("String_Node_Str" + exchange.getRequestMethod() + "String_Node_Str"+ exchange.getRequestURI());
    respond(new ErrorResponse(HttpStatusCode.BAD_REQUEST,"String_Node_Str" + "String_Node_Str"),exchange);
    return;
  }
  try {
switch (key) {
case ("String_Node_Str"):
      downloadHandler.handleGET(exchange);
    return;
case ("String_Node_Str"):
  uploadHandler.handleGET(exchange);
return;
case ("String_Node_Str"):
uploadHandler.handlePOST(exchange);
return;
}
}
 catch (Exception e) {
Debug.log("String_Node_Str");
return;
}
String json=readBody(exchange);
if (json.isEmpty()) json="String_Node_Str";
Debug.log("String_Node_Str" + json);
Command command=null;
try {
command=gson.fromJson(json,commandClass);
}
 catch (Exception e) {
Debug.log("String_Node_Str");
respond(new ErrorResponse(HttpStatusCode.INTERNAL_SERVER_ERROR,"String_Node_Str"),exchange);
return;
}
Debug.log(command.getClass().getName());
HashMap<String,String> query=new HashMap<>();
String uri;
try {
uri=Util.parseURI(exchange.getRequestURI(),query);
}
 catch (Exception e) {
Debug.log("String_Node_Str");
respond(new ErrorResponse(HttpStatusCode.INTERNAL_SERVER_ERROR,"String_Node_Str"),exchange);
return;
}
if (command.getExpectedNumberOfURIFields() != calculateURILength(uri)) {
Debug.log("String_Node_Str" + exchange.getRequestMethod() + "String_Node_Str"+ exchange.getRequestURI());
Debug.log("String_Node_Str" + command.getExpectedNumberOfURIFields() + "String_Node_Str"+ calculateURILength(uri));
respond(new ErrorResponse(HttpStatusCode.BAD_REQUEST,"String_Node_Str" + "String_Node_Str"),exchange);
return;
}
UserType userType=UserType.UNKNOWN;
if (!commandClass.equals(PostLoginCommand.class)) {
try (DatabaseAccessor db=Command.initDB()){
userType=db.getRole(Authenticate.getUsernameByID(uuid));
}
 catch (SQLException|IOException e) {
Debug.log(e.toString());
ErrorResponse errorResponse=new ErrorResponse(HttpStatusCode.INTERNAL_SERVER_ERROR,"String_Node_Str" + "String_Node_Str");
respond(errorResponse,exchange);
}
}
command.setFields(uri,query,Authenticate.getUsernameByID(uuid),userType);
try {
command.validate();
}
 catch (ValidateException e) {
Debug.log(e.getMessage());
ErrorLogger.log("String_Node_Str",e.getMessage());
respond(new ErrorResponse(e.getCode(),e.getMessage()),exchange);
return;
}
if (commandClass.equals(ProcessCommands.class)) {
respond(new ProcessResponse(HttpStatusCode.NOT_IMPLEMENTED),exchange);
}
 else {
respond(command.execute(),exchange);
}
}