Why does hashmap map report an error during compilation?

Hashmap <int, string> map = new hashmap <int, string> (); <br/> map. put (1, "A"); <br/> map. put (2, "B"); <br/> map. put (1, "AQ"); <br/> system. out. println (map. get (0); <br/> system. out. println (map. get (1); <br/> system. out. println (map. get (2 ));

This piece of code is interesting. You can guess the answer. The logic is okay, but the compilation won't work.

Error: syntax error on token "int", dimensions expected after this token

Cause:Reference TypeAndOriginal TypeNot clear!

Java provides two different types:Reference TypeAndOriginal Type (or built-in type).IntYesJavaThe original data type,IntegerYesJavaIsIntProvided encapsulation class.JavaEncapsulation classes are provided for each original type.

Original Type encapsulation class

Boolean

Char character

Byte byte

Short short

Int integer

Long long

Float float

Double double

The behavior of the reference type and the original type is completely different, and they have different semantics. The reference type and the original type have different features and usage, they include: size and speed problems, which type of data structure is stored, the default value specified when the reference type and original type are used as instance data of a class. The default value of the instance variables referenced by the object is null, and the default value of the original type of instance variables is related to their types.

Hashmap <integer, string> map = new hashmap <integer, string> (); <br/> map. put (1, "A"); <br/> map. put (2, "B"); <br/> map. put (1, "AQ"); <br/> system. out. println (map. get (0); <br/> system. out. println (map. get (1); <br/> system. out. println (map. get (2 ));