Java Exception Handling and streams - exception

Before closing the stream and after reaching the end of stream marker, a program tries to read the stream again.
__error
__checked exception
__compile error
__no exception

Use the following code :
try{
// your code
} catch ( Exception e ) {
throws RuntimeException(e);
}
I hope this works

you can also try this...
I have personal experience this will surely work.
public static void main(String Args[]) throws Exception

Related

AssertJ assert on Exception covered another Exception

I'm a beginner of AssertJ. I encountered some issue when I use AssertJ to do Unit Testing.
JAVA: version 8
AssertJ: 3.11.1
I have a source code as below, to capture an exception and throw another exception.
try {
Integer.valueOf(valueA);
} catch(Exception e) {
throw new XXXException("value is not valid", e);
}
My test case as below failed, and I was told wrong exception assert, it's a bit confusing.
Throwable thrown = catchThrowable(() -> {
contract.init(ctx, "A", "100A", "B", "200");
});
assertThat(thrown).isInstanceOf(XXXException.class);
The error message as below, it seems like the original exception was captured by AssertJ. Anyone can help? Is it a bug or my mistake of AssertJ API usage? Many Thanks.
java.lang.AssertionError:
Expecting:
<java.util.IllegalFormatConversionException: d != java.lang.String>
to be an instance of:
<xxxx.XXXException>
but was:
<"java.util.IllegalFormatConversionException: d != java.lang.String
Here's my attempt to reproduce the issue, the test passes as expected:
#Test
public void test() {
Throwable thrown = catchThrowable(() -> f());
assertThat(thrown).isInstanceOf(RuntimeException.class);
}
private void f() {
try {
Integer.valueOf("100A");
} catch (Exception e) {
throw new RuntimeException("value is not valid", e);
}
}
Can you show us what contract.init is doing?
Another possibility would be in the stack trace, if it contains a %d somewhere stack trace it might be interpreted by a String.format but hard to say without more details.

How to catch the original Exception, when using WebServices?

After searching for days now and reading pretty much everything related to that, I'm finally posting my question here, since I couldn't find a solution for my specific problem.
I want my REST WebServices to return the original Exception, that has been thrown or at least the correct StackTrace. To test this, I'm using JUnit integrationtests and Wildfly 13 as app-server. After researching I found 2 possible solutions.
1.Using Exception Mappers
While this magical thing catches all of my Exceptions and allows me to return a Response, I've noticed that my StackTrace is changed if I use it like in the example. For example, "com.test.TestClass" is turned into "null.thread" or "null.interceptor". It seems like somehow the exception is changed on the way and the paths to the class are lost or censored, but I can't make sense of it.
Also I couldn't find any restrictions for the Response.entity, be it size, datatype or security.
As far as I understand, you can catch the ExceptionMapper Response OR a WebApplicationException, which contains the response. In my case, the response in the WebApplicationException contains all the relevant data except the (correct) StackTrace.
2.Using WebApplicationException
Another Solution would be to simply throw WebApplicationException instead of ECEException and not using a mapper. If I do that and catch it, the Exception is empty though. It doesn't contain any of the data set, it's always 500 - InternalServerError (I guess, Wildfly couldn't handle it then and threw an exception itself).
Or is it not supposed to be catched/thrown like that? Do I need to convert it to JSon or can I expect it to simply work out of the box with my annotations in the WebServiceInterface and the Response MediaType? Does it even make sense to put a full Response within a WebApplicationException? I mean, both contain fields for the ErrorCode, which seems redundand, even though there is a constructor for that approach.
Long story short:
What's the best approach to catch all possible exceptions and retrieve the full stack trace? Reading this post, I guess catching all "Exception"s is fine and they are always returned as WebApplicationExceptions, but the stack trace is still gone/malformed... your thoughts?
**JUnitTest**
#Test
public void testCreateTask_ClusterInvalid() throws IOException {
final RPETask taskToCreate = new RPETask();;
try
{
final long tid = taskManagerWebService.createTask(taskToCreate);
}
catch (WebApplicationException e) //Responses are ALWAYS catched as WebApplicationException
{
Response response = e.getResponse();
String emString = response.readEntity(String.class);
Gson gson = new Gson();
ECEWebErrorMessage errorMessage = gson.fromJson(emString, ECEWebErrorMessage.class);
errorMessage.displayErrorInformationOnConsole();
}
}
**WebServiceInterface**
#POST
#Path(URI_CREATE_TASK)
#Consumes(WebServiceNames.JSON)
#Produces(WebServiceNames.JSON)
long createTask(final RPETask task) throws ECEException;
**WebService**
#Override
public long createTask(final RPETask task) throws ECEException {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("createTask(" + task + ")");
}
return taskManager.createTask(task);
}
**ManagerBeanInterface**
long createTask(RPETask task) throws ECEException;
**ManagerBean**
#Override
public long createTask(final RPETask task) throws ECEException {
final ClusterEngineBean cluster = find(ClusterEngineBean.class, task.getCluster());
if (cluster == null) {
throw new ECEObjectNotFoundException(ClusterEngineBean.class, task.getCluster());
}
}
**ExceptionMapper**
#Provider
public class GenericWebExceptionMapper implements ExceptionMapper<Exception> {
final Log logger = LogFactory.getLog(getClass());
#Override
public Response toResponse(Exception ex) {
//At this point, the Exception is fully available -> Sending it as Response breaks it!
logger.error("GenericWebExceptionMapper -> toResponse(Throwable ex)", ex);
ECEWebErrorMessage errorMessage = new ECEWebErrorMessage(500,
ex.getMessage(),
ex.getClass().getCanonicalName(),
ex.getStackTrace());
return Response.status(Status.INTERNAL_SERVER_ERROR)
.entity(errorMessage)
.type(MediaType.APPLICATION_JSON)
.build();
}
}
After more research I've finally found a solution for myself.
Why is the StackTrace gone/malformed?
It's for security reasons. Wildfly automatically detects outgoing StackTraces and censors them, using interceptors. Im not sure if you can do anything about that, but I guess you shouldn't do that anyway.
What is the best approach?
Using Exception Mappers worked for me. Instead of catching them as WebApplicationException, you can always expect a response with the appropriote error code and handle them that way. For example error code 200 = OK, do this... error code 404 = NOTFOUND, do that...I that case your WebServices should always return Responses and contain the object you want to retreive in the entity field of the Response.
Feel free to add additional information to this solution.

Webdriver test Script Does not stop after assert failure

In my webdriver script I have the three methods
setup, test and tearDown
following the junit convention.
In the test method I have few asserts like this
#Test
public void testStudentHome() throws Exception {
String classCode = "I6OWW";
Utilities.studentSignin(driver, baseUrl);
assertEquals(true, sth.openNotification());
assertEquals("My Scores", sth.myScores(true));
}
The sth is the PageObject on which I am performing the tests and that I have created in the setup method.
I am calling all these three methods from a main method like this:
public static void main(String[] args) {
StudentHomeTest sht = new StudentHomeTest();
try {
sht.setup();
sht.testStudentHome();
sht.tearDown();
} catch (Exception ex) {
Logger.getLogger(StudentHomeTest.class.getName()).log(Level.SEVERE, null, ex);
sht.tearDown();
}
}
Now while running the test if some assertion fails the test method should (this is what I expect) throw an exception and the main method should call the tearDown method. But this does not happen. and the browser window continues to stay there.
I am using the netbeans ide for running the test.
following the junit convention
If you follow the jUnit convention, then you will know that teardown methods belong in the #After method as this method will always run after your tests.
create a new method with the #After jUnit annotation.
#After
public void tearDown() {
sht.tearDown();
}
Edit
You know what, I believe that you are running into a classic issue of assertEquals in jUnit.
Stolen from this answer...:
JUnit calls the .equals() method to determine equality in the method assertEquals(Object o1, Object o2).
So, you are definitely safe using assertEquals(string1, string2). (Because Strings are Objects)
--
Instead of using assertEquals on these calls, use assertTrue() instead.
assertTrue(sth.openNotification());
assertTrue("My Scores".equals(sth.myScores(true)));
AssertionError doesn't extend Exception - it's a Throwable.
But in any case, you should have
try {
sht.setup();
sht.testStudentHome();
} finally {
sht.tearDown();
}
No need for a catch block. main can throw Exception.

Exception assertion along with other assertions jUnit

I have a method that throws exception. And i have a test like this.
#Rule
public ExpectedException expectedEx = ExpectedException.none();
#Test
public void shouldThrowExceptionIfValidationFails() throws Exception {
doThrow(new InvalidException("Invalid Token")).when(obj).foo(any());
expectedEx.expect(InvalidException.class);
expectedEx.expectMessage("Invalid Token");
// my method call
// verify DB save doesn't happens
assertTrue(false);
}
The test assert for exception, and since the exception is thrown the test passes. It doesn't care about the last line assertTrue(false)
How can i make sure that my other assertions are also satisfied.
This is the pattern I follow for this case. It uses ExpectedException as designed. I like the throw e rather than failing after method method call in the try because it will not result in a false-positive if someone decides to delete the fail (which people have a tendency to do when they see fail() or if a test is failing because it hits a fail()).
#Test
public void shouldThrowExceptionIfValidationFails() throws Exception {
doThrow(new InvalidException("Invalid Token")).when(obj).foo(any());
expectedEx.expect(InvalidException.class);
expectedEx.expectMessage("Invalid Token");
try{
// my method call
}catch(InvalidException e){
// verify DB save doesn't happens
assertTrue(false);
throw e;
}
}

How can I test if a particular exception is not thrown?

Can I test whether a particular Exception is not thrown?
The other way round is easy using #Test[expect=MyException].
But how can I negate this?
If you want to test if a particular Exception is not thrown in a condition where other exceptions could be thrown, try this:
try {
myMethod();
}
catch (ExceptionNotToThrow entt){
fail("WHOOPS! Threw ExceptionNotToThrow" + entt.toString);
}
catch (Throwable t){
//do nothing since other exceptions are OK
}
assertTrue(somethingElse);
//done!
You can do the following using assertj
if you want to check if exception is not thrown then
Throwable throwable = catchThrowable(() -> sut.method());
assertThat(throwable).isNull();
or you expect to throw
Throwable throwable = catchThrowable(() -> sut.method());
assertThat(throwable).isInstanceOf(ClassOfExecption.class)
.hasMessageContaining("expected message");
catch-exception makes the example of Freiheit a bit more concise:
catchException(a).myMethod();
assertFalse(caughtException() instanceof ExceptionNotToThrow);
Another latest solution could be using Junit5 assertDoesNotThrow:
assertDoesNotThrow( () -> myMethod() , "MyException is not thrown")
Use #Test(expected = Test.None::class) (in Kotlin)