Filebot null pointer exception code#

The times array is ready to be used, because it is made of a primitive type: they are initialized with a default value, which is 0 (zero) for int and float (and char, etc.), false for booleans, null for objects (including String). The arrays are an interesting special case. The most usual causes is forgetting to put the image, putting it at the wrong place (not in the data folder), mistyping the name (including case errors in non-Windows systems), having a corrupted file, etc. In this case, that's loadImage() that returned null because it couldn't load the image. You can also have a NPE when trying to use sprite. Player = new Player(width / 2, height / 2, true) The solution is simple: just remove the type, which transforms the re-declaration into a simple assignment: So, when setup() is finished, the global player remains uninitialized, and you will get the dreaded NPE when trying to use it. This line actually declares a ''''new'''' player local variable, that just hides the global variable of same name, and that disappears at the end of setup() (its scope). Can you see it? It is a quite common error meet by beginners. There is an error in the last line of setup() above. Of course, don't initialize twice: no need to do an init at declaration level if you need to initialize in setup(), the first value will just be lost. Player player = new Player(width / 2, height / 2, true) // Intentional mistake here! Positions = new PVector // width is known only after the call to size() Sprite = loadImage('scene.jpg') // Costly call Size(500, 500) // Remember! This call should be the first one of setup().

Idem when you need values available only when setup() is run.

Filebot null pointer exception code#

Sometime, you can initialize the object at the declaration site:Īnd sometime you need to initialize them in the code itself, usually in setup() as lot of objects are expensive to create (particularly when loading data from the disk) and this operation should be done once. You need to initialize them before using them. If you try to use these objects in this state, you will get NPEs:Īll these lines will raise a NullPointerException. So, when you declare a global object, it is null: Processing does that a lot, because it wants to avoid exposing exceptions to users, as they are quite complex to handle. It is also often used as return value from functions supposed to return an object, to indicate an error has happened and the object isn't available. Some of these errors come from a programming error, so you just fix the error to get rid of it (we will see that for NPE here), others, like not being able to open a file, must be handled by a try / catch construct, but that's outside of the scope of this article.Īnd what is Null, or, rather, null? It is a special Java value, indicating that an object reference hasn't been initialized yet (or have been reset). Your program, or some class, throws an exception when an unrecoverable error happens (programming mistake, file isn't there, program can't connect to network, etc.) and should be handled at a higher level (by the programmer).

Java has no pointers but references, which fill the same role, in a safer way (no risk of memory corruption!).Īn Exception is a language mechanism allowing to handle exceptional cases, usually errors. Null? Pointer? Exception?įirst, what is this name? It is one of the most misnamed class of Java, because this language has no pointers! This has probably historical roots, when people wrote the Java compiler in C or C++, where the word 'pointer' comes from. Fortunately, it is also one of the easiest to fix, once the most common cases are known. One of the most common errors in Java (hence, in Processing) is this NullPointerException (short-named NPE).