Code:-
try { Assert.assertEquals("1", "2"); } catch (Exception e) { System.out.println("I am in error block"); }
If the assert statements fails, I would like to capture the error in the catch block. I am trying with the above code and its not happening.
Will the assertion error be caught by in a catch block for java exception?
In order to catch the assertion error, we need to declare the assertion statement in the try block with the second expression being the message to be displayed and catch the assertion error in the catch block.
Yes, we can catch an error. The Throwable class is the superclass of all errors and exceptions in the Java language. Only objects that are instances of this class (or one of its subclasses) are thrown by the Java Virtual Machine or can be thrown by the throw statement.
AssertionError is an Unchecked Exception which rises explicitly by programmer or by API Developer to indicate that assert statement fails. If x is not greater than 10 then you will get runtime exception saying AssertionError. Wrong. Errors are not Exceptions.
As is documented, try/catch blocks can't handle StackOverflowException and OutOfMemoryException.
You have almost answered your own question. Your catch block will not catch the AssertionError
that the Assert
throws if it fails, because it is an Error
(or, more specifically, it extends java.lang.Error
). See the docs for more information on this. Your catch block only catches Throwable
objects that extend java.lang.Exception
If you really want to catch it - you need to use
catch (AssertionError e) { ...
However, as others have mentioned, this is a very unusual way to use assertions - they should usually pass and if they fail it is very unusual for you to want to carry on program execution. That's why the failure throws an Error
rather than an Exception
. You can read more about (not) catching Error
in this question.
Are you sure you don't just want a test - if ( variableName == "1")
?
NB if you are testing unit-test helper code, like a matcher, it might make sense to catch the AssertionError
.
If you want to catch both Exception
and Error
instances use:
... catch (Throwable t) { ... }
Since both Exception
and Error
extend Throwable
.
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