The principle behind using strings in JAVA7 switch statements

First look at the code and the post-compilation code:

/** * @author Doctor * * @time March 28, 2015 PM 3:26:06 */public class Stringforswitch {@Rulepublic expectedexception ex = EXP Ectedexception.none (); @Testpublic void Test_string_switch () {string result= ""; Switch ("Doctor") {case "doctor": Result = "Doctor"; break;default:break;} Assertthat (Result, Equalto ("Doctor")); }

Post-compilation Code:

public class stringforswitch {     @Rule     public  Expectedexception ex = expectedexception.none ();    public  Stringforswitch ()  {    }     @Test     public  void test_string_switch ()  {        string result  =  "";        string var2 =  "Doctor";         switch ("Doctor". Hashcode ())  {         case -1326477025:             if (Var2.equals ("Doctor"))  {                 result =  "Doctor";             }        default:             Assert.assertthat (Result, isequal.equalto ("Doctor"));         }     }}

1. The string type is implemented in a switch statement by comparing the value of hashcode with the content of the string.

2. Because the hash value of a string may be duplicated, the hash function is poorly designed. It is also necessary to further compare the contents of the string.

3. Compiler-level syntax sugar just doesn't change,switch is a comparison of integers.

4. JDK1.8.0_40 environment.

The principle behind using strings in JAVA7 switch statements