How do I create some variable type alias in Java

Question

let say I have this code

Map<String, String> list = new HashMap<String, String>(); list.put("number1", "one"); list.put("number2", "two"); 

how can I make some "alias" the type

Map<String, String> 

to something that easier to be rewritten like

// may be something like this theNewType = HashMap<String, String>;  theNewType list = new theNewType(); list.put("number1", "one"); list.put("number2", "two"); 

basically my question is, how to create "alias" to some "type", so i can make it easier to write and easier when need to change the whole program code.

Thanks, and sorry if this is silly question. I'm kinda new in Java.

Answer 1

There are no aliases in Java. You can extend the HashMap class with your class like this:

public class TheNewType extends HashMap<String, String> {     // default constructor     public TheNewType() {         super();     }     // you need to implement the other constructors if you need } 

But keep in mind that this will be a class it won't be the same as you type HashMap<String, String>

Answer 2

There is no typedef equivalent in Java, and there is no common idiom for aliasing types. I suppose you could do something like

class StringMap extends HashMap<String, String> {} 

but this is not common and would not be obvious to a program maintainer.