Java7 string in the switch statement of the syntax sugar

Jdk7 a constant in a new switch statement can be of type string,

For example:

@Testpublic void Test_1 () {String string = "Hello"; switch (string) {case "Hello": System.out.println (String); Default:throw New IllegalArgumentException ("illegal parameter");}}

Behind the syntactic sugar, its practical treatment of string types, using the Hashcode () method to convert.

Therefore, the string type cannot be null.

For example:

@Testpublic void Test_3 () {String string = Null;expectedexception.expect (nullpointerexception.class); switch (String) { Case "Hello": System.out.println (String); Break;default:throw new IllegalArgumentException ("illegal parameter");}}

Will throw an exception

NullPointerException

Java7 string in the switch statement of the syntax sugar