This is the third question I’ve seen in two days that’s been caused by people re-initializing fields that have been @FXML-injected by the FXMLLoader. The point of @FXML is that you tell the FXMLLoader to initialize that field with the object that was created by parsing the FXML file. When you then execute btnBrowse = … Read more
Try removing the .metadata folder from your workspace. This holds all your configurations, even after a new install. I think if you just delete this folder, assuming everything is in place, you should be up and running again.
The return type of the conditional expression b ? d1.doubleValue : d2 is double. A conditional expression must have a single return type. Following the rules for binary numeric promotion, d2 is autounboxed to a double, which causes a NullPointerException when d2 == null. From the language spec, section §15.25: Otherwise, if the second and … Read more
The null pointer exception is a result of unboxing the result of inverse.get(animal). If inverse doesn’t contain the key animal, it returns null, “of type” Integer. Given that the assignment is to an int reference, Java unboxes the value into an int, resulting in a null pointer exception. You should either check for inverse.containsKey(animal) or … Read more
This happens because Gson uses an unsafe (as in java.misc.Unsafe) instance construction mechanism to create instances of classes, bypassing their constructors, and then sets their fields directly. See this Q&A for some research: Gson Deserialization with Kotlin, Initializer block not called. As a consequence, Gson ignores both the construction logic and the class state invariants, … Read more
Now with the 23.1.1 release of the design support library, you can use View header = navigationView.getHeaderView(0) TextView text = (TextView) header.findViewById(R.id.textView);
I had exactly the same error, although with other and more simpler code than yours. I found out that the problem occurred only if I didn’t close the app in the emulator after re-run it from eclipse. So if I close it before run it from eclipse, everything works fine. But since I am really … Read more
NullPointerException means that mp is null. This means the MediaPlayer.create() failed. Does R.raw.alarm exist?
I would recommend you never throw NullPointerException by yourself. The main reason not to do this, as Thorbjørn Ravn Andersen says in a comment below, is that you don’t wan’t to mix ‘real, bad NPEs’ with NPEs thrown intentionally. So, until you’re confident that you’re able to recognize ‘valid’ NPE, I’d recommend to use IllegalArgumentException … Read more
NullPointerException is a run-time exception which is not recommended to catch it, but instead avoid it: if(someVariable != null) someVariable.doSomething(); else { // do something else }