By using a cast you’re essentially telling the compiler “trust me. I’m a professional, I know what I’m doing and I know that although you can’t guarantee it, I’m telling you that this animal variable is definitely going to be a dog.” Since the animal isn’t actually a dog (it’s an animal, you could do … Read more
Ok, I figured this one out. I got rid of the runtime error by programatically setting the View’s LayoutParams to ListView LayoutParams, like so: headerView.setLayoutParams(new ListView.LayoutParams(ListView.LayoutParams.FILL_PARENT, ListView.LayoutParams.WRAP_CONTENT)); before adding the view. The reason being is found in the Android docs: http://developer.android.com/reference/android/view/View.html#setLayoutParams(android.view.ViewGroup.LayoutParams) which states that: These supply parameters to the parent of this view specifying how … Read more
This can happen if two different classloaders load a class named AutocompleteResult. These two classes are then treated as entirely different classes, even if they have the same package and name (and even implementation/fields/methods). A common cause for this is if you use some kind of plugin system and both your base classes and the … Read more
With the following method call List<MyModelClass> myModelClass=(List<MyModelClass>) restTemplate.postForObject(url,mvm,List.class); All Jackson knows is that you want a List, but doesn’t have any restriction on the type. By default Jackson deserializes a JSON object into a LinkedHashMap, so that’s why you are getting the ClassCastException. If your returned JSON is an array, one way to get it … Read more
You are passing the Application Context not the Activity Context with getApplicationContext(); Wherever you are passing it pass this or ActivityName.this instead. Since you are trying to cast the Context you pass (Application not Activity as you thought) to an Activity with (Activity) you get this exception because you can’t cast the Application to Activity … Read more
We can cast an int to a double but we can’t do the same with the wrapper classes Integer and Double: int a = 1; Integer b = 1; // inboxing, requires Java 1.5+ double c = (double) a; // OK Double d = (Double) b; // No way. This shows the compile time error … Read more
It looks like this has been reported as a Java bug. It appears to be caused by using annotations from a 3rd party library (like JUnit) and not including the jar with that annotation in the javadoc invocation. If that is the case, just use the -classpath option on javadoc and include the extra jar … Read more
One reason could be that the part of the code inserting the object uses a different classloader than the code retrieving it. An instance of a class can not be cast to the same class loaded by a different classloader. Response to the edit: What would you do if this happened in production? This generally … Read more
I am not quite following your description of the program flow, but usually when you get ClassCastExceptions you cannot explain you have loaded the class with one classloader then try to cast it to the same class loaded by another classloader. This will not work – they are represented by two different Class objects inside … Read more
Straight from the API Specifications for the ClassCastException: Thrown to indicate that the code has attempted to cast an object to a subclass of which it is not an instance. So, for example, when one tries to cast an Integer to a String, String is not an subclass of Integer, so a ClassCastException will be … Read more