Well, I've tried to understand and read what could cause it but I just can't get it:
I have this somewhere in my code:
try{
..
m.invoke(testObject);
..
} catch(AssertionError e){
...
} catch(Exception e){
..
}
Thing is that, when it tries to invoke some method it throws InvocationTargetException
instead of some other expected exception (specifically ArrayIndexOutOfBoundsException
). As I actually know what method is invoked I went straight to this method code and added a try-catch block for the line that suppose to throw ArrayIndexOutOfBoundsException
and it really threw ArrayIndexOutOfBoundsException
as expected. Yet when going up it somehow changes to InvocationTargetException
and in the code above catch(Exception e)
e is InvocationTargetException
and not ArrayIndexOutOfBoundsException
as expected.
What could cause such a behavior or how can I check such a thing?
You've added an extra level of abstraction by calling the method with reflection. The reflection layer wraps any exception in an InvocationTargetException
, which lets you tell the difference between an exception actually caused by a failure in the reflection call (maybe your argument list wasn't valid, for example) and a failure within the method called.
Just unwrap the cause within the InvocationTargetException
and you'll get to the original one.
The exception is thrown if
InvocationTargetException - if the underlying method throws an exception.
So if the method, that has been invoked with reflection API, throws an exception (runtime exception for example), the reflection API will wrap the exception into an InvocationTargetException
.
Use the getCause()
method on the InvocationTargetException
to retrieve the original exception.
From the Javadoc of Method.invoke()
Throws: InvocationTargetException - if the underlying method throws an exception.
This exception is thrown if the method called threw an exception.
java.lang.reflect.Proxy
instances augmenting a wrapped object. Each Proxy
gracefully handles a specific exception (possibly thrown by the wrapped object) by using its own InvocationHandler
. For an exception to ripple through this cascade until reaching the correct invocation handler/proxy, in each InvocationHandler
, I would catch InvocationTargetException
, unwrap it, check if the wrapped exception is an instanceof
the exception to be handled by this InvocationHandler
. If it's not an instanceof
, I would throw the unwrapped exception... right?
This will print the exact line of code in the specific method, which when invoked, raised the exception:
try {
// try code
..
m.invoke(testObject);
..
} catch (InvocationTargetException e) {
// Answer:
e.getCause().printStackTrace();
} catch (Exception e) {
// generic exception handling
e.printStackTrace();
}
That InvocationTargetException
is probably wrapping up your ArrayIndexOutOfBoundsException
. There is no telling upfront when using reflection what that method can throw -- so rather than using a throws Exception
approach, all the exceptions are being caught and wrapped up in InvocationTargetException
.
This describes something like,
InvocationTargetException is a checked exception that wraps an exception thrown by an invoked method or constructor. As of release 1.4, this exception has been retrofitted to conform to the general purpose exception-chaining mechanism. The "target exception" that is provided at construction time and accessed via the getTargetException() method is now known as the cause, and may be accessed via the Throwable.getCause() method, as well as the aforementioned "legacy method."
You can compare with the original exception Class using getCause() method like this :
try{
...
} catch(Exception e){
if(e.getCause().getClass().equals(AssertionError.class)){
// handle your exception 1
} else {
// handle the rest of the world exception
}
}
I had a java.lang.reflect.InvocationTargetException
error from a statement calling a logger object in an external class
inside a try
/ catch
block in my class
.
Stepping through the code in the Eclipse debugger & hovering the mouse over the logger statement I saw the logger object
was null
(some external constants needed to be instantiated at the very top of my class
).
A problem can also be that the targetSdkVersion is upped and that you use deprecated Gradle manifest features. Try lowering the targetSdkVersion again and see if it works. In my case it was targetSdkVersion 31 -> 30
This exception is thrown if the underlying method(method called using Reflection) throws an exception.
So if the method, that has been invoked by reflection API, throws an exception (as for example runtime exception), the reflection API will wrap the exception into an InvocationTargetException.
I was facing the same problem. I used e.getCause().getCause() then I found that it was because of wrong parameters I was passing. There was nullPointerException in fetching the value of one of the parameters. Hope this will help you.
Invocation Target Exception:
I strongly believe that any naming convention has diligent thoughts invested in it. And, it is more than likely that our questions have their answers in the names, if we tried finding a rationale behind the name.
Let's break the name up into 3 parts. "Exception" has occurred when "Invoking" a "Target" method. And, the exception is thrown with this wrapper when, a method is invoked via reflection in Java. While executing the method, there could be any type of exception raised. It is by design, that the actual cause of the exception is abstracted away, to let the end user know that the exception was one that occurred during a reflection based method access. In order to get the actual cause, it is recommended that the exception is caught and ex.getCause()
is called. Best practice is to, in fact throw the cause from the catch block that caught the InvocationTargetException
try{
method.invoke();
} catch(InvocationTargetException ite) {
throw ite.getCause();
} catch(Exception e) {
// handle non-reflection originated exceptions
throw e;
}
I know it is similar to the other answers, but I wanted to make it more clear about "when" this exception type is generated by Java, so that it is a mystery to none.
List all jar files from the Eclipse Navigator mode Verify that all the jar files are in binary mode
The error vanished after I did Clean->Run xDoclet->Run xPackaging.
In my workspace, in ecllipse.
Success story sharing
InvocationTargetException
", I just discovered that if you've got it printed usingexception.printStackTrace()
, you just look at the "Caused By:" section instead of the top half/normal section.try {...} catch (InvocationTargetException ex) { log.error("oops!", ex.getCause()) }
or...catch... { throw ex.getCause() }
you just look at the "Caused By:" section instead of the top half/normal section