primitive

Given a double variable named sizeValue and sizeValue contains something other than 0, what is the most efficient way to determine that sizeValue contains a value that is an integer? Currently i'm using sizeValue % 1 == 0 any other faster ways? give a try to Math.ceil : private static boolean isInt(double x) { return x == Math.ceil(x); } EDIT I've done some benchmarks with the following methods: private static boolean isInt1(double x) { return x == (int) x; } private static boolean isInt2(double x) { return x == Math.ceil(x); } private static boolean isInt3(double x) { return x % 1 == 0; }

BACKGROUND : I am trying to implement a tiny template, i.e. generic class, which would allow me to achieve a pass-by-reference functionality as follows. public static class Ref<T> { T value; public Ref(T InitValue) { this.set(InitValue); } public void set(T Value) { this.value = Value; } public T get() { return this.value; } } So, I could define a function that takes a 'Ref' where the value can actually be changed, e.g. public static void function(Ref<Byte> x) { x.set((byte)0x7E); } The initialization of the variable to be passed by reference looks not so elegant. Ref<Byte> to_be_changed = new

K.Sierra in her book "SCJP Study Guide" mentions "We know that a literal integer is always an int, but more importantly, the result of an expression involving anything int-sized or smaller is always an int." I've started experimenting and I'm a little bit confused with the below results: byte a = 1; // correct byte b = 1 + a; // incorrect (needs explicit casting) byte c = 1 + 1; // correct (I expected it to be incorrect) Could anyone explain to me why the last example does not require casting? Why does the Java compiler put the implicit cast? Is it because there are 2 int literals?

This question is derived from: How to get this Method object via reflection? I'm trying to do the following: Class c1 = Class.forName("[Ljava.lang.Integer;"); // works fine Class c1 = Class.forName("[Lint;"); // doesn't work, since it's primitive What is the workaround? int[].class is the only solution? Class c1 = Class.forName("[I"); See javadoc of Class.getName() for details. According to this page use: Class intArray = Class.forName("[I"); 来源： https://stackoverflow.com/questions/5076690/how-to-create-a-class-of-primitive-array

I am having a strange problem with ModelAttribute in Spring MVC 3.0. When I deploy the app at localhost, it works fine. But when I deploy the app on a remote server, it fails everytime user access a specific action, with the errors: ERROR: my.package.application.web.filter.ExceptionFilter - long.<init>() java.lang.NoSuchMethodException: long.<init>() at java.lang.Class.getConstructor0(Class.java:2706) at java.lang.Class.getDeclaredConstructor(Class.java:1985) at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:104) at org.springframework.web.bind.annotation.support

Example code : int main() { std::vector<int> v1{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; std::cout << "Printing v1" << std::endl; print(v1); std::vector<int> v2(std::make_move_iterator(v1.begin()), std::make_move_iterator(v1.end())); std::cout << "Printing v1" << std::endl; print(v1); std::cout << "Printing v2" << std::endl; print(v2); std::vector<std::string> v3{"some", "stuff", "to", "put", "in", "the", "strings"}; std::cout << "Printing v3" << std::endl; print(v3); std::vector<std::string> v4(std::make_move_iterator(v3.begin()), std::make_move_iterator(v3.end())); std::cout << "Printing v3" << std: