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Why isn't try/catch Exceptions working for Gson.fromJson()?

I've been getting com.google.gson.JsonSyntaxException from calling Gson.fromJson(), so added a catch(Exception) logic, but the error is never getting caught and just getting thrown!
Here's what I have:
Request request = new Request.Builder()
.url(getOrderUrlWithId)
.get()
.build();
try {
Response response = this.okHttpClient.newCall(request).execute();
GetOrderResult orderResult = gson.fromJson(gson.toJson(response.body().string()), GetOrderResult.class);
response.close();
} catch (IOException e) {
log.error("Error retrieving order : " + e.getMessage(), e);
throw new RuntimeException(e);
} catch (Exception e) {
log.error("Error happening for client PO: " + clientPO, e);
return null;
}
When I run the test I get "com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
"
Why isn't the error getting caught?
Here's the Stack trace:
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:226)
at com.google.gson.Gson.fromJson(Gson.java:927)
at com.google.gson.Gson.fromJson(Gson.java:892)
at com.google.gson.Gson.fromJson(Gson.java:841)
at com.google.gson.Gson.fromJson(Gson.java:813)
at com.hub.fulfill.circlegraphics.getOrdersByCgOrderId(CircleGraphicsApi.java:164)

You need to catch JsonSyntaxException like this
For Kotlin
catch(e: JsonSyntaxException){
//show toast/snackabar/log here
}
For Java
catch(JsonSyntaxException e){
//show toast/snackabar/log here
}
Earlier I was also catching java.lang.IllegalStateException but it didn't worked.
Seems the root exception here is JsonSyntaxException and thus, we need to catch this one.
It worked for me!

when(...).thenReturn(null) points that you use some mocking library (jMock, Mockery or simular). And you define that if fromJson("test", Fulfillment.class) is called mock should return null. Actual method fromJson is not invoked as you already defined result.
If you want expection to be thrown, then remove line
when(gson.fromJson("test", Fulfillment.class)).thenReturn(null);

Figured it out. So turns out #Slf4j's log.error() call shows the exception as an error in Google StackDriver, hence telling me I've been getting millions of errors.

Parallel processing using collection of CompletableFuture supplyAsync then collecting results

//Unit of logic I want to make it to run in parallel
public PagesDTO convertOCRStreamToDTO(String pageId, Integer pageSequence) throws Exception {
LOG.info("Get OCR begin for pageId [{}] thread name {}",pageId, Thread.currentThread().getName());
OcrContent ocrContent = getOcrContent(pageId);
OcrDTO ocrData = populateOCRData(ocrContent.getInputStream());
PagesDTO pageDTO = new PagesDTO(pageId, pageSequence.toString(), ocrData);
return pageDTO;
}
Logic to execute convertOCRStreamToDTO(..) in parallel then collect its results when individuals thread execution is done
List<PagesDTO> pageDTOList = new ArrayList<>();
//javadoc: Creates a work-stealing thread pool using all available processors as its target parallelism level.
ExecutorService newWorkStealingPool = Executors.newWorkStealingPool();
Instant start = Instant.now();
List<CompletableFuture<PagesDTO>> pendingTasks = new ArrayList<>();
List<CompletableFuture<PagesDTO>> completedTasks = new ArrayList<>();
CompletableFuture<<PagesDTO>> task = null;
for (InputPageDTO dcInputPageDTO : dcReqDTO.getPages()) {
String pageId = dcInputPageDTO.getPageId();
task = CompletableFuture
.supplyAsync(() -> {
try {
return convertOCRStreamToDTO(pageId, pageSequence.getAndIncrement());
} catch (HttpHostConnectException | ConnectTimeoutException e) {
LOG.error("Error connecting to Redis for pageId [{}]", pageId, e);
CaptureException e1 = new CaptureException(Error.getErrorCodes().get(ErrorCodeConstants.REDIS_CONNECTION_FAILURE),
" Connecting to the Redis failed while getting OCR for pageId ["+pageId +"] " + e.getMessage(), CaptureErrorComponent.REDIS_CACHE, e);
exceptionMap.put(pageId,e1);
} catch (CaptureException e) {
LOG.error("Error in Document Classification Engine Service while getting OCR for pageId [{}]",pageId,e);
exceptionMap.put(pageId,e);
} catch (Exception e) {
LOG.error("Error getting OCR content for the pageId [{}]", pageId,e);
CaptureException e1 = new CaptureException(Error.getErrorCodes().get(ErrorCodeConstants.TECHNICAL_FAILURE),
"Error while getting ocr content for pageId : ["+pageId +"] " + e.getMessage(), CaptureErrorComponent.REDIS_CACHE, e);
exceptionMap.put(pageId,e1);
}
return null;
}, newWorkStealingPool);
//collect all async tasks
pendingTasks.add(task);
}
//TODO: How to avoid unnecessary loops which is happening here just for the sake of waiting for the future tasks to complete???
//TODO: Looking for the best solutions
while(pendingTasks.size() > 0) {
for(CompletableFuture<PagesDTO> futureTask: pendingTasks) {
if(futureTask != null && futureTask.isDone()){
completedTasks.add(futureTask);
pageDTOList.add(futureTask.get());
}
}
pendingTasks.removeAll(completedTasks);
}
//Throw the exception cought while getting converting OCR stream to DTO - for any of the pageId
for(InputPageDTO dcInputPageDTO : dcReqDTO.getPages()) {
if(exceptionMap.containsKey(dcInputPageDTO.getPageId())) {
CaptureException e = exceptionMap.get(dcInputPageDTO.getPageId());
throw e;
}
}
LOG.info("Parallel processing time taken for {} pages = {}", dcReqDTO.getPages().size(),
org.springframework.util.StringUtils.deleteAny(Duration.between(Instant.now(), start).toString().toLowerCase(), "pt-"));
Please look at my above code base todo items, I have below two concerns for which I am looking for advice over stackoverflow:
1) I want to avoid unnecessary looping (happening in while loop above), what is the best way for optimistically I wait for all threads to complete its async execution then collect my results out of it??? Please anybody has an advice?
2) ExecutorService instance is created at my service bean class level, thinking that, it will be re-used for every requests, instead create it local to the method, and shutdown in finally. Am I doing right here?? or any correction in my thought process?

Simply remove the while and the if and you are good:
for(CompletableFuture<PagesDTO> futureTask: pendingTasks) {
completedTasks.add(futureTask);
pageDTOList.add(futureTask.get());
}
get() (as well as join()) will wait for the future to complete before returning a value. Also, there is no need to test for null since your list will never contain any.
You should however probably change the way you handle exceptions. CompletableFuture has a specific mechanism for handling them and rethrowing them when calling get()/join(). You might simply want to wrap your checked exceptions in CompletionException.

Java ProgramCall.run hangs

Busy trying to Call RPG function from Java and got this example from JamesA. But now I am having trouble, here is my code:
AS400 system = new AS400("MachineName");
ProgramCall program = new ProgramCall(system);
try
{
// Initialise the name of the program to run.
String programName = "/QSYS.LIB/LIBNAME.LIB/FUNNAME.PGM";
// Set up the 3 parameters.
ProgramParameter[] parameterList = new ProgramParameter[2];
// First parameter is to input a name.
AS400Text OperationsItemId = new AS400Text(20);
parameterList[0] = new ProgramParameter(OperationsItemId.toBytes("TestID"));
AS400Text CaseMarkingValue = new AS400Text(20);
parameterList[1] = new ProgramParameter(CaseMarkingValue.toBytes("TestData"));
// Set the program name and parameter list.
program.setProgram(programName, parameterList);
// Run the program.
if (program.run() != true)
{
// Report failure.
System.out.println("Program failed!");
// Show the messages.
AS400Message[] messagelist = program.getMessageList();
for (int i = 0; i < messagelist.length; ++i)
{
// Show each message.
System.out.println(messagelist[i]);
}
}
// Else no error, get output data.
else
{
AS400Text text = new AS400Text(50);
System.out.println(text.toObject(parameterList[1].getOutputData()));
System.out.println(text.toObject(parameterList[2].getOutputData()));
}
}
catch (Exception e)
{
//System.out.println("Program " + program.getProgram() + " issued an exception!");
e.printStackTrace();
}
// Done with the system.
system.disconnectAllServices();
The application Hangs at this lineif (program.run() != true), and I wait for about 10 minutes and then I terminate the application.
Any idea what I am doing wrong?
Edit
Here is the message on the job log:
Client request - run program QSYS/QWCRTVCA.
Client request - run program LIBNAME/FUNNAME.
File P6CASEL2 in library *LIBL not found or inline data file missing.
Error message CPF4101 appeared during OPEN.
Cannot resolve to object YOBPSSR. Type and Subtype X'0201' Authority
FUNNAME insert a row into table P6CASEPF through a view called P6CASEL2. P6CASEL2 is in a different library lets say LIBNAME2. Is there away to maybe set the JobDescription?

Are you sure FUNNAME.PGM is terminating and not hung with a MSGW? Check QSYSOPR for any messages.
Class ProgramCall:
NOTE: When the program runs within the host server job, the library list will be the initial library list specified in the job description in the user profile.

So I saw that my problem is that my library list is not setup, and for some reason, the user we are using, does not have a Job Description. So to over come this I added the following code before calling the program.run()
CommandCall command = new CommandCall(system);
command.run("ADDLIBLE LIB(LIBNAME)");
command.run("ADDLIBLE LIB(LIBNAME2)");
This simply add this LIBNAME, and LIBNAME2 to the user's library list.

Oh yes, the problem is Library list not set ... take a look at this discussion on Midrange.com, there are different work-around ...
http://archive.midrange.com/java400-l/200909/msg00032.html
...
Depe

JAVA::CORBA NameComponent nameService.rebind results in an exception java.lang.NullPointerException

I got the following JAVA CORBA Server code which I am trying to debug.
Code snippet (not the all code) is below. The code is running without any problem. But, When I uncomment the "nameService.rebind(countName" I get the following exception:
java.lang.NullPointerException
It looks to me that the issue related to the countName array. Any idea what can cause to the Exception?
// bind the Count object in the Naming service
NameComponent[] countName = new NameComponent [1000];
for(int i=1;i<1000;i++){
countName[i] = new NameComponent ("+i+", "");
}
// nameService.rebind(countName,
// myPOA.servant_to_reference(countServant));
System.out.println(myPOA.servant_to_reference(countServant)
+ " is ready.");

Your NameComponent[0] is NULL here. Change the code to
NameComponent[] countName = new NameComponent [1000];
for(int i=0;i<1000;i++){
countName[i] = new NameComponent ("+i+", "");
}
In your code you starting your loop from 1 , but you should have started from 0

Java Play framework parsing JSON error

I want to setup Janrain authentication to my Play! project which is hosted on GAE and uses GAE module. But I get the following error while I try to login:
RuntimeException occured : Cannot parse JSON (check logs)
And Play highlighs the following line as error:
JsonElement rpxJson = rpxRequest.get().getJson();
Here is method that I use for token callback:
public static void tokenCallback(String token) {
Properties p = Play.configuration;
// Try the driver
String rpxApi = p.getProperty("login.rpx.apiKey");
WSRequest rpxRequest = WS.url("http://rpxnow.com/api/v2/auth_info");
// get RPX
rpxRequest.setParameter("token", token);
rpxRequest.setParameter("apiKey", rpxApi);
JsonElement rpxJson = rpxRequest.get().getJson();
JsonElement profile = rpxJson.getAsJsonObject().get("profile");
String identifier = profile.getAsJsonObject().getAsJsonPrimitive("identifier").getAsString();
welcome(identifier);
}
And here is the error that I get from terminal:
Internal Server Error (500) for request POST /login/tokencallback
Execution exception (In /app/controllers/Login.java around line 27)
RuntimeException occured : Cannot parse JSON (check logs)
play.exceptions.JavaExecutionException: Cannot parse JSON (check logs)
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:237)
at Invocation.HTTP Request(Play!)
Caused by: java.lang.RuntimeException: Cannot parse JSON (check logs)
at play.libs.WS$HttpResponse.getJson(WS.java:668)
at controllers.Login.tokenCallback(Login.java:27)
at play.mvc.ActionInvoker.invokeWithContinuation(ActionInvoker.java:557)
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:508)
at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:484)
at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:479)
at play.mvc.ActionInvoker.invoke(ActionInvoker.java:161)
... 1 more
Caused by: com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Expected EOF at line 2 column 1
at com.google.gson.JsonParser.parse(JsonParser.java:65)
at com.google.gson.JsonParser.parse(JsonParser.java:45)
at play.libs.WS$HttpResponse.getJson(WS.java:665)
... 7 more
Caused by: com.google.gson.stream.MalformedJsonException: Expected EOF at line 2 column 1
at com.google.gson.stream.JsonReader.syntaxError(JsonReader.java:1310)
at com.google.gson.stream.JsonReader.peek(JsonReader.java:390)
at com.google.gson.JsonParser.parse(JsonParser.java:60)
... 9 more
What can I do? Please, help me to solve this problem.
Thanks in advance.

OK, Here is my first suggestion. Try using the HTTPS connection for the URL. I ran into some problems with the HTTP connection. Here is how I do the Janrain connection:
WSRequest rpxRequest = WS.url("https://rpxnow.com/api/v2/auth_info");
// get RPX
rpxRequest.setParameter("token", token);
rpxRequest.setParameter("apiKey", rpxApi);
HttpResponse res = null;
try {
res = rpxRequest.post();
} catch (JavaExecutionException ex) {
Log.error("unknown error ", ex);
Validation.addError("", "Unknown Error: please try again");
Validation.keep();
Secure.login();
} catch (Exception ex) {
Log.error("Most likely SSL error", ex);
Validation.addError("", "SSL Error: please try again");
Validation.keep();
Secure.login();
}
if (res.getStatus() != 200) {
Log.error("status 200 error");
Validation.addError("", "Status 200 error: please try again");
Validation.keep();
Secure.login();
}
JsonElement rpxJson = res.getJson();
JsonElement profile = rpxJson.getAsJsonObject().get("profile");
JsonObject profileJson = profile.getAsJsonObject();

Having called the URL http://rpxnow.com/api/v2/auth_info , it immediately redirects to https://rpxnow.com/api/v2/auth_info (http s ). I suspect you don't get the JSON answer, but a http redirect code in your call to the web service.
Two possibilites:
1) Change the web service call to https://rpxnow.com/api/v2/auth_info , this probably solves your problem, failing that;
2) Change the line JsonElement rpxJson = rpxRequest.get().getJson(); into something like
HttpResponse httpResponse = rpxRequest.get();
Logger.log ( httpResponse.getString() );
if ( httpResponse.success() ) {
JsonElement rpxJson = httpResponse.getJson();
} else {
// fail gracefully
}
and report back on the contents of the answer which gets logged in the second line.