non-nullable

This is a question on how to gracefully circumvent the nullability of init in NSObject class. So here is a classic objective-c implementation: + (instancetype)sharedInstance { static dispatch_once_t onceToken; static id sharedInstance; dispatch_once(&onceToken, ^ { sharedInstance = [[self alloc] init]; }); return sharedInstance; } But now I want to declare it as nonnull , if possible: + (nonnull instancetype)sharedInstance; Unfortunately, init returns a nullable instancetype value. Should I add an NSAssert or something after calling init ? I noticed that some people even document nonnull

When configuring Eclipse 4.2.0 to perform a null analysis (configured to use @javax.annotation.Nonnull etc.), the following code will generate the warning Null type safety: The expression of type int needs unchecked conversion to conform to '@Nonnull Integer' class C { static void foo(int i) { bar(i); // Warning } static void bar(@javax.annotation.Nonnull Integer i) { } } How am I supposed to fix this (without using @SuppressWarnings("null") )? It seems that the analyzer does not know that boxed primitives cannot be null . I think it's a bug in Eclipse. I tried the same with IntelliJ, and it

Xcode has recently added __nonnull , __nullable , etc. attributes. However, they're not supported by older versions of clang and other compilers. How can I use these attributes in a compatible way? I hoped something like this would work: #ifndef NS_ASSUME_NONNULL_BEGIN #define __nonnull #endif but it seems that NS_ASSUME_NONNULL_BEGIN is not a real macro, and it's "not defined" in Xcode7. And it would make sense for this to work: #if !defined(__is_identifier) || __is_identifier(__nonnull) #define __nonnull #define __nullable #endif but Xcode 6 chokes on that with "token is not a valid binary

I get a warning from eclipse and I know I can remove it with suppress warning but I'd prefer to understand what makes it thing it could be null. package-info.java @ParametersAreNonnullByDefault package test; import javax.annotation.ParametersAreNonnullByDefault; test.java package test; public class Test { public static void main( final String[ ] args ) { System.out.println( new Test( "a" ).getS( ) ); } private final String s; public Test( final String s ) { this.s = s; } public String getS( ) { return this.s;//Null type safety: The expression of type String needs unchecked conversion to

I am trying to use django-orderedmodel ( https://github.com/kirelagin/django-orderedmodel ) in my project. Running makemigrations doesn't work: You are trying to add a non-nullable field 'order' to slide without a default; we can't do that (the database needs something to populate existing rows). Please select a fix: 1) Provide a one-off default now (will be set on all existing rows) 2) Quit, and let me add a default in models.py Select an option: I would like to know where I'm doing this wrong. Thanks As the order field is unique, you'll need to add the field in several migration steps,