记录遍历到的当前List中的element,所以在 foreach中操作的对象是指向临时变量的,而不是List中的element实例对象的地址,结果自然就只是修改临时变量的值并没修改List中的element,所以才会出现:foreach增强for循环中修改List中element的值是无效的问题; 解决办法: 改用loop without size实行; 问题2:Itera
}// New Enhanced For loopSystem.out.println("\n===> 2. New Enhanced For loop Example..");for(String temp : crunchifyList) { System.out.println(temp); }// Iterator - Returns an iterator over the elements in this list in proper sequence.System.out.println("\n===> 3. Iterator Exa...
List<String> actors = Arrays.asList("Jack Nicholson", "Marlon Brando", "Robert De Niro", "Al Pacino", "Tom Hanks"); 1. Let’s start looking at the for loop evolution over different java releases. 让我们开始研究不同Java版本上的for循环演变。 (Basic for loop) Main elements of, “for...
1for(String s : listNames) {2System.out.println(s);3} The enhanced for loop actually uses an iterator behind the scenes. That means the Java compiler will convert the enhanced for loop syntax to iterator construct when compiling. The new syntax just gives the programmers a more convenient ...
原文链接:http://www.trinea.cn/android/arraylist-linkedlist-loop-performance/ 主要介绍ArrayList和LinkedList这两种list的五种循环遍历方式,各种方式的性能测试对比,根据ArrayList和LinkedList的源码实现分析性能结果,总结结论。 通过本文你可以了解(1)List的五种遍历方式及各自性能 (2)foreach及Iterator的实现 (3)加深...
System.out.println("over"); } if就是如果的意思。括号里边是条件表达式,只要是条件表达式,就会有true 和false。 那么我就通过if 语句控制来了某些语句的执行。条件满足就会执行if 控制区间内的代码,什么是控制区间,就是一对{}之间的。 如果if 控制的语句只有一条那么,括号可以省略不写.也就是说如果if 后没...
super E> action) { int i, hi, mc; // hoist accesses and checks from loop ArrayList<E> lst; Object[] a; if (action == null) throw new NullPointerException(); if ((lst = list) != null && (a = lst.elementData) != null) { if ((hi = fence) < 0) { mc = lst.modCount...
System.out.println("\n===> 2. New Enhanced For loop Example.."); for(Stringtemp : crunchifyList){ System.out.println(temp); } // Iterator - Returns an iterator over the elements in this list in proper sequence. System.out.println...
Loop over a collection of items and process each one in turn. choose (case statement) for conditional processing (section 9.2) Branch to one of multiple processing paths depending on an input value. Generating numbers (section 7.7) Dynamically generate numbered sections, numbered elements, and nume...
} // end of for loop over annotationMirrors // An @Entity annotation was encountered and is ready to be added to // the JAXB EntityMappings element as a sub-element. if ( (entity.getName() != null) && (!entity.getName().isEmpty()) ) ...