type-erasure

问题 I am writing the function that can catch exceptions of the certain type only. def myFunc[A <: Exception]() { try { println("Hello world") // or something else } catch { case a: A => // warning: abstract type pattern A is unchecked since it is eliminated by erasure } } What is the corrent way to bypass jvm type erasure in such case? 回答1: You could use ClassTag like in this answer. But I'd prefer this approach: def myFunc(recover: PartialFunction[Throwable, Unit]): Unit = { try { println("Hello

问题 I was going through TypeErasure topic at http://download.oracle.com/javase/tutorial/java/generics/erasure.html which says that compiler removes all information related to type parameters and type arguments within a class or method. Now considering the code below public class Box<T> { private T t; // lineA, T stands for "Type" public void add(T t) { // lineB this.t = t; // lineC } public T get() { // lineD return t; // lineE } } Now inside main method I have below code snippet Box<String> box1

问题 I was going through TypeErasure topic at http://download.oracle.com/javase/tutorial/java/generics/erasure.html which says that compiler removes all information related to type parameters and type arguments within a class or method. Now considering the code below public class Box<T> { private T t; // lineA, T stands for "Type" public void add(T t) { // lineB this.t = t; // lineC } public T get() { // lineD return t; // lineE } } Now inside main method I have below code snippet Box<String> box1

问题 I am trying to understand why writing both methods in a class is not allowed public bool plus(List<String>) {return true;} public bool plus(List<Integer>) {return true;} I try to figure how it is related to type erasure but when I decompile the following code public class Test<T> { boolean plus2(List<T> ss) {return false;} boolean plus(List<String> ss) {return false;} boolean plus(Set<Integer> ss) {return false;} } I get the same when I decompile it with Java decompiler (jd) Even when I print

问题 This question already has answers here : Closed 9 years ago . Possible Duplicate: Java how to: Generic Array creation I want to create a Stack which contains 10 elements, I'm trying to do this with Generics. I started by creating a Stack class of Type T, but I'm getting compilation error when I try to instantiate the array of generic type. public class Stack<T>{ private T[] stk = new T[10]; } What I'm doing wrong here? 回答1: You can't do this. Not without using some hacky round about code, and

问题 This question already has answers here : Closed 9 years ago . Possible Duplicate: Java how to: Generic Array creation I want to create a Stack which contains 10 elements, I'm trying to do this with Generics. I started by creating a Stack class of Type T, but I'm getting compilation error when I try to instantiate the array of generic type. public class Stack<T>{ private T[] stk = new T[10]; } What I'm doing wrong here? 回答1: You can't do this. Not without using some hacky round about code, and

问题 I have two overloaded method having following signatures - def fun(x: Seq[String]): Future[Seq[Int]] = ??? def fun(x: Seq[(String, String)]): Future[Seq[Int]] = ??? Due to type erasure, these methods can't be overloaded and hence showing compilation error. I tried using typetags as a workaround - def fun[t: TypeTag](values: Seq[T]): Future[Seq[Int]] = { typeOf[T] match { case t if t =:= typeOf[String] => ??? case t if t =:= typeOf[(String, String)] => ??? case _ => ??? // Should not come here

问题 Sean Parent's talk, Inheritance is the base class of evil, says that polymorphism is not a property of the type, but rather a property of how it is used. As a thumb rule, don't use inheritance to implement interfaces. Among the many benefits of this is the devirtualization of classes which have virtual functions only because they were implementing an interface. Here's an example : class Drawable { public: virtual void draw() = 0; }; class DrawA : public Drawable { public: void draw() override

来源： https://stackoverflow.com/questions/61150873/how-to-deserialize-generic-listt-with-jackson

来源： https://stackoverflow.com/questions/62501668/type-erasure-in-a-nested-list-with-a-given-context-bound