String b = new String("abc"); // DON'T DO THIS

  您可以用多种方式来创建字符串。每次创建字符串，Java虚拟机都会在背后创建一个String对象。下面有两种创建字符串对象的方式，并且将字符串对象赋值给一个变量：

String a = "abc";
String b = new String("abc"); // DON'T DO THIS

  避免使用第二种方式[2]。第二种方式创建了两个String对象，这样降低了性能：首先，Java虚拟机创建了String对象“abc”。然后，java虚拟机创建一个新的String对象，并把字符串“abc”传入构造函数。同样重要的是，这是一次不必要的构造，使得您的代码阅读起来更加困难。



  You can construct Strings in a number of ways. Any time you create a new String literal, the Java VM constructs a String object behind the scenes. Here are two ways to construct a String object and assign it to a reference variable:

String a = "abc";
String b = new String("abc"); // DON'T DO THIS

  Avoid the second technique.[2] It creates two String objects, which can degrade performance: First, the VM creates the literal String object "abc". Second, the VM constructs a new String object, passing the literal "abc" to its constructor. Equally as important, it is an unnecessary construct that makes your code more difficult to read.