finally

public void testFinally(){ System.out.println(setOne().toString()); } protected StringBuilder setOne(){ StringBuilder builder=new StringBuilder(); try{ builder.append("Cool"); return builder.append("Return"); }finally{ builder=null; /* ;) */ } } why output is CoolReturn, not null? Regards, Mahendra Athneria The expression is evaluated to a value in the return statement, and that's the value which will be returned. The finally block is executed after the expression evaluation part of the return statement. Of course, the finally block could modify the contents of the object referred to by the

Inspired from the other topic , I wrote this code which simulates a finally block: #include <cassert> #include <iostream> struct base { virtual ~base(){} }; template<typename TLambda> struct exec : base { TLambda lambda; exec(TLambda l) : lambda(l){} ~exec() { lambda(); } }; class lambda{ base *pbase; public: template<typename TLambda> lambda(TLambda l): pbase(new exec<TLambda>(l)){} ~lambda() { delete pbase; } }; class A{ int a; public: void start(){ int a=1; lambda finally = [&]{a=2; std::cout<<"finally executed";}; try{ assert(a==1); //do stuff } catch(int){ //do stuff } } }; int main() { A

#揭开JVM所看到的try/catch/finally 最近有一位朋友发了一段代码给我，这个方法很简单，具体内容大致如下： int num = 5000000;//500万 long begin = System.currentTimeMillis(); for(int i=0; i<num; i++){ try{ //do something }catch(Exception e){ } } long end = System.currentTimeMillis(); System.out.println("==============使用时间：" + (end - begin) + " 毫秒"); 上面代码可以看到是通过执行该循环体所消耗的时间，通过和把 try/cache 注释掉进行对比，最后得到的结果时间比较随机，执行的耗时和 try/cache 没有必然的联系，那 try/cache 究竟会不会影响代码的执行效率呢？从java语言的源码上看貌似多执行了一些指令，实际上是怎么样的呢？下面我分几个场景来分析一下jvm对 try/cache 的处理过程。 ##单层的try/catch 下面是一个只有单层的 try/catch 代码块 public int test(int a,int b){ try{ return a+b; }catch (Exception e){

Bjarne Stroustrup writes in his C++ Style and Technique FAQ , emphasis mine: Because C++ supports an alternative that is almost always better : The "resource acquisition is initialization" technique (TC++PL3 section 14.4). The basic idea is to represent a resource by a local object, so that the local object's destructor will release the resource. That way, the programmer cannot forget to release the resource. For example: class File_handle { FILE* p; public: File_handle(const char* n, const char* a) { p = fopen(n,a); if (p==0) throw Open_error(errno); } File_handle(FILE* pp) { p = pp; if (p==0

来源： https://www.cnblogs.com/wqbin/p/11803948.html

This question already has answers here : In Java, what purpose do the keywords `final`, `finally` and `finalize` fulfil? (6 answers) Often these keywords confuse me. Can any one tell me exactly what the difference between them is? final keyword class On a class it means you forbid to have a child class extending yours. public final class finalClass Attribute/Field final MyObject value = new MyObject() means you won't be able to modify the instance of the object. value = xxxx won't be allowed, but you still can modify the object itself value.field = "xxx"; Method When you use final on a method,