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Mockito to test the catch block of private method

I need to write a test to verify that when an IOException is thrown by the private method_C, Method_B returns True.
But
public final class A{
public static Boolean Method_B(){
try{
//call a private method C which throws IOException
Method_C
}
catch(final IOException e) {
return Boolean.True
}
}
private static Method_C() throws IOException {
return something;
}
What I tried:
#Test
public void testSomeExceptionOccured() throws IOException {
A Amock = mock(A.class);
doThrow(IOException.class).when(Amock.Method_C(any(),any(),any(),any()));
Boolean x = A.Method_B(some_inputs);
Assert.assertEquals(Boolean.TRUE, x);
}
I am getting compilation errors :
1.Cannot mock a final class
2. Method_C has private access in A
Any suggestions on how this can be rectified?

you are required to use finally in try catch
import java.io.*;
public class Test {
public static Boolean Method_B() {
try {
System.out.println("Main working going..");
File file = new File("./nofile.txt");
FileInputStream fis = new FileInputStream(file);
} catch (IOException e) {
// Exceptiona handling
System.out.println("No file found ");
} catch (Exception e) {
// Exceptiona handling
System.out.println(e);
} finally {
return true;
}
}
public static void main(String args[]) {
if (Test.Method_B()) {
System.out.println("Show true ans");
} else {
System.out.println("Sorry error occure");
}
}
}

How to avoid dummy return in try catch block while a method which throws exception is called?

I know it is required that in a non-void method, return or throw is a must.
But I don't like the dummy return in catch block in such case:
public int call() throws Exception {
try {
return calcMethod();
} catch (Exception e) {
process(e);
return 0;
}
}
protected void process(Exception e) throws xxxException {
if ( isTypeAException(e) ) { throw new TypeAException() ; }
else if ( isTypeBException(e) ) { throw new TypeBException() ; }
else ( isTypeCException(e) ) { throw new TypeCException() ; }
}
...
process will certainly throws an exception, then why return is still required in catch block?

In one sense, throwing the exception in process() is to be construed as "a problem with processing", which is also not what you mean.
As you want the exception to be raised by call(), so the solution here is to make process() an exception factory:
public int call() throws Exception {
try {
return calcMethod();
} catch (Exception e) {
throw process(e);
}
}
protected xxxException process(Exception e) throws xxxException {
if (isTypeAException(e))
return new TypeAException();
else if (isTypeBException(e))
return new TypeBException();
else
return new TypeCException();
}

JUnit expected exception not working as expected

i am trying to test a private method inside an ActionListener. The method should throw an exception if an invalid url is passed:
Heres the code of my test:
#Rule
public ExpectedException expectedException = ExpectedException.none();
Map<JLabel, JTextField> inputs;
ActionListener listener;
AddStationWindow window;
ArrayList<Station> stationsToDelete;
#Before
public void setUp() throws IllegalAccessException, NoSuchFieldException,
InstantiationException, SQLException, ClassNotFoundException {
inputs = new HashMap<JLabel, JTextField>();
window = new AddStationWindow();
stationsToDelete = new ArrayList<>();
InitializeH2Database.initialiteDatabase();
}
#Test
public void saveStation() throws NoSuchFieldException,
IllegalAccessException, MalformedURLException, NoSuchMethodException,
InvocationTargetException {
Field f = window.getClass().getDeclaredField("inputElements");
f.setAccessible(true);
LinkedHashMap<JLabel, JTextField> inputs = (LinkedHashMap<JLabel,
JTextField>) f.get(window);
Field f2 = window.getClass().getDeclaredField("save");
f2.setAccessible(true);
JButton saveButton = (JButton) f2.get(window);
inputs.get(window.getInputLabels().get(0)).setText("Testsender");
inputs.get((window.getInputLabels().get(1))).setText("asdasdsa");
ActionListener listener = saveButton.getActionListeners()[0];
Method m = listener.getClass().getDeclaredMethod("saveStation");
m.setAccessible(true);
m.invoke(listener);
expectedException.expect(MalformedURLException.class);
}
#After
public void tearDown() {
stationsToDelete.forEach(s ->
H2DatabaseConnector.getInstance().deleteStation(s));
}
This is the tested method inside the ActionListener:
private boolean saveStation() {
List<JLabel> keys = new ArrayList<>();
for (Map.Entry<JLabel, JTextField> inputElement : inputElements.entrySet()) {
keys.add(inputElement.getKey());
}
String stationName = inputElements.get(keys.get(0)).getText();
String urlString = inputElements.get(keys.get(1)).getText();
URL stationURL = null;
try {
stationURL = new URL(urlString);
} catch (MalformedURLException e) {
JOptionPane.showMessageDialog(window, "Invalid URL!", "URL
not valid", JOptionPane.ERROR_MESSAGE);
e.printStackTrace();
return false;
}
Station s = new Station(stationName, stationURL);
if (checkStation(s)) {
return WebradioPlayer.addStation(s);
}
return false;
}
If i run the test, i can see that the stack tarce shows the malformed url exception with message no protocol: 'asdasdsa', but the test fails.
Can someone explain me why? JUnit version is 4.

You have to set the expected exception before you call the code that actually does throw the exception.
Instead of
#Test
public void saveStation() throws ... {
// code here
expectedException.expect(MalformedURLException.class);
}
you should write the test method as
#Test
public void saveStation() throws ... {
expectedException.expect(MalformedURLException.class);
// code here
}
Additionally, you have to change your method saveStation to not suppress the exception if you actually want to have it thrown. See #Leviand's answer for more details.

Your test is failing because you are expecting an exception to be thrown (you said invalid url exception), but you are wrapping that exception into a try catch, then you are printing the stacktrace.
try {
stationURL = new URL(urlString);
} catch (MalformedURLException e) {
JOptionPane.showMessageDialog(window, "Invalid URL!", "URL
not valid", JOptionPane.ERROR_MESSAGE);
e.printStackTrace();
return false;
}
you have to add the trown declaration in your catch, or not catch it at all, ie:
} catch (MalformedURLException e) {
JOptionPane.showMessageDialog(window, "Invalid URL!", "URL
not valid", JOptionPane.ERROR_MESSAGE);
e.printStackTrace();
throw new MalformedURLException(e);
}
and add the throw info to your method
private boolean saveStation() throws MalformedURLException{

Java - How to throw exception outside an anonymous class

try
{
if(ruleName.equalsIgnoreCase("RuleName"))
{
cu.accept(new ASTVisitor()
{
public boolean visit(MethodInvocation e)
{
if(rule.getConditions().verify(e, env, parentKeys, astParser, file, cu)) // throws ParseException
matches.add(getLinesPosition(cu, e));
return true;
}
});
}
// ...
}
catch(ParseException e)
{
throw AnotherException();
}
// ...
I need to catch thrown exception in the bottom catch, but I cannot overload method via throws construction. How to do with that, please advice? Thanks

Create custom exception, write try catch block in anonymous class and catch it in your catch block.
class CustomException extends Exception
{
//Parameterless Constructor
public CustomException () {}
//Constructor that accepts a message
public CustomException (String message)
{
super(message);
}
}
now
try
{
if(ruleName.equalsIgnoreCase("RuleName"))
{
cu.accept(new ASTVisitor()
{
try {
public boolean visit(MethodInvocation e)
{
if(rule.getConditions().verify(e, env, parentKeys, astParser, file, cu)) // throws ParseException
matches.add(getLinesPosition(cu, e));
return true;
}
catch(Exception e){
throw new CustomException();
}
});
}
// ...
}
catch(CustomException e)
{
throw AnotherException();
}

As suggested already, an unchecked exception could be used. Another option is to mutate a final variable. Eg:
final AtomicReference<Exception> exceptionRef = new AtomicReference<>();
SomeInterface anonymous = new SomeInterface() {
public void doStuff() {
try {
doSomethingExceptional();
} catch (Exception e) {
exceptionRef.set(e);
}
}
};
anonymous.doStuff();
if (exceptionRef.get() != null) {
throw exceptionRef.get();
}

Guice doesn't initialize property

I'm newly with Guice.
I want to use Guice for initializing object without writing new directly.
Here is my main():
public class VelocityParserTest {
public static void main(String[] args) throws IOException {
try {
PoenaRequestService poenaService = new PoenaRequestService();
System.out.println(poenaService.sendRequest("kbkCode"));
} catch (PoenaServiceException e) {
e.printStackTrace();
}
}
}
PoenaRequestService:
public class PoenaRequestService {
private static final String TEMPLATE_PATH = "resources/xml_messages/bp12/message01.xml";
public static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(PoenaRequestService.class);
#Inject
#Named("poena_service")
private HttpService poenaService;
public String sendRequest(/*TaxPayer taxPayer,*/ String kbk) throws PoenaServiceException {
LOG.info(String.format("Generating poena message request for string: %s", kbk));
Map<String, String> replaceValues = new HashMap<>();
replaceValues.put("guid", "guid");
replaceValues.put("iinbin", "iinbin");
replaceValues.put("rnn", "rnn");
replaceValues.put("taxOrgCode", "taxOrgCode");
replaceValues.put("kbk", "kbk");
replaceValues.put("dateMessage", "dateMessage");
replaceValues.put("applyDate", "applyDate");
ServiceResponseMessage result;
try {
String template = IOUtils.readFileIntoString(TEMPLATE_PATH);
Document rq = XmlUtil.parseDocument(StringUtils.replaceValues(template, replaceValues));
result = poenaService.execute(HttpMethod.POST, null, rq);
} catch (IOException e) {
throw new PoenaServiceException("Unable to read template file: " + TEMPLATE_PATH, e);
} catch (SAXException e) {
throw new PoenaServiceException("Unable to parse result document, please check template file: " + TEMPLATE_PATH, e);
} catch (HttpServiceException e) {
throw new PoenaServiceException(e);
}
if (result.isSuccess()) {
return (String) result.getResult();
}
throw new PoenaServiceException("HTTP service error code '" + result.getStatusCode() + "', message: " + result.getStatusMessage());
}
}
When I tried to debug this I see next picture:
As e result I got NullPointerException.
I couldn't figure out this behavior. Why does this exactly happen?
Any suggestions?

It's not working because you're not actually using Guice. You need to create an injector and bind your dependencies to something. Something akin to this:
public class VelocityParserTest {
public static void main(String[] args) throws IOException {
Injector injector = Guice.createInjector(new AbstractModule() {
#Override
protected void configure() {
bind(PoenaRequestService.class).asEagerSingleton();
bind(HttpService.class)
.annotatedWith(Names.named("poena_service"))
.toInstance(...);
}
});
try {
PoenaRequestService poenaService = injector.getInstance(PoenaRequestService.class);
System.out.println(poenaService.sendRequest("kbkCode"));
} catch (PoenaServiceException e) {
e.printStackTrace();
}
}
}