boxing

I'm new to programming, As per MSDN , Boxing is the process of converting a value type to the type object or to any interface type implemented by this value type. When the CLR boxes a value type, it wraps the value inside a System.Object and stores it on the managed heap. Unboxing extracts the value type from the object. Boxing is implicit; unboxing is explicit. I knew We can store any objects in an arraylist, because system.object is a base for all all types. Boxing and unboxing happens in array list. I agree with that. Will boxing and unboxing happens in an array? Because We can create

I'm having trouble understanding how values of boxed traits come into existence. Consider the following code: trait Fooer { fn foo(&self); } impl Fooer for i32 { fn foo(&self) { println!("Fooer on i32!"); } } fn main() { let a = Box::new(32); // works, creates a Box<i32> let b = Box::<i32>::new(32); // works, creates a Box<i32> let c = Box::<Fooer>::new(32); // doesn't work let d: Box<Fooer> = Box::new(32); // works, creates a Box<Fooer> let e: Box<Fooer> = Box::<i32>::new(32); // works, creates a Box<Fooer> } Obviously, variant a and b work, trivially. However, variant c does not, probably

I have some questions about the following code: using System; namespace ConsoleApplication2 { public struct Disposable : IDisposable { public void Dispose() { } } class Program { static void Main(string[] args) { using (Test()) { } } static Disposable Test() { return new Disposable(); } } } My questions are: Will the using-statement that operates on the Disposable struct, returned from Test() box the struct, or not? How can I find the answer myself? To try to find out myself, I inspected the IL produced by the above code, and here's the IL for the Main(...) method: .method private hidebysig

I am little bit confused in boxing and unboxing. According to its definition Boxing is implicit conversion of ValueTypes to Reference Types (Object). UnBoxing is explicit conversion of Reference Types (Object) to its equivalent ValueTypes. the best example for describing this is int i = 123; object o = i; // boxing and o = 123; i = (int)o; // unboxing But my question is that whether int is value type and string is reference type so int i = 123; string s = i.ToString(); and s = "123"; i = (int)s; Is this an example of boxing and unboxing or not??? Calling ToString is not boxing. It creates a

Is there a standard method I can use in place of this custom method? public static Byte[] box(byte[] byteArray) { Byte[] box = new Byte[byteArray.length]; for (int i = 0; i < box.length; i++) { box[i] = byteArray[i]; } return box; } Joachim Sauer No, there is no such method in the JDK. As it's often the case, however, Apache Commons Lang provides such a method . Enter Java 8, and you can do following (boxing): int [] ints = ... Integer[] boxedInts = IntStream.of(ints).boxed().toArray(Integer[]::new); However, this only works for int[] , long[] , and double[] . This will not work for byte[] .

####关于Arrays.asList(T)这个API 参考: https://docs.oracle.com/javase/tutorial/java/generics/why.html https://docs.oracle.com/javase/tutorial/java/data/autoboxing.html 所以会研究这个问题,是因为在写代码的时候遇到了这个,很反直觉. 同样都是{120,130}竟然返回了不同的类型. public static void main(String[] args) { Integer[] pangs = {120, 130}; int[] fats = {120, 130}; List<Integer> pangList = Arrays.asList(pangs); List<int[]> fatsList = Arrays.asList(fats); } Auto boxing is the automatic conversion that the Java compiler makes, between the primitive types and their corresponding object wrapper classes . Generic Types A generic type is a generic

My question is somewhat related to this one: Explicitly implemented interface and generic constraint . My question, however, is how the compiler enables a generic constraint to eliminate the need for boxing a value type that explicitly implements an interface. I guess my question boils down to two parts: What is going on with the behind-the-scenes CLR implementation that requires a value type to be boxed when accessing an explicitly implemented interface member, and What happens with a generic constraint that removes this requirement? Some example code: internal struct TestStruct : IEquatable