May be the title will misguide you.
String str ="abcd";
In the above code String is a class and without using new we can create an object with value. Now I have a class Number.java in which I have to assign some number as shown below.
Number no = 23;
How to create such class.
I would normally say that you should be using Operator Overloading. But this feature does not exist in Java.
See here: Operator overloading in Java
You can't directly assign value to Object like Strings.
If you really want to achieve the same thing, I would suggest you to create a Factory of pre-defined initialized objects and get the required object from Factory by using Prototype pattern or FactoryMethod pattern.
Sample code:
import java.util.concurrent.atomic.*;
public class PrototypeFactory
{
public class NumberPrototype
{
public static final String THIRTY_TWO = "32";
public static final String FORTY_ONE = "41";
}
private static java.util.Map<String , AtomicInteger> prototypes = new java.util.HashMap<String , AtomicInteger>();
static
{
prototypes.put(NumberPrototype.THIRTY_TWO, new AtomicInteger(32));
prototypes.put(NumberPrototype.FORTY_ONE, new AtomicInteger(43));
}
public static AtomicInteger getInstance( final String s) {
//return (AtomicInteger)(prototypes.get(s)).clone();
return ((AtomicInteger)prototypes.get(s));
}
public static void main(String args[]){
System.out.println("Prototype.get(32):"+PrototypeFactory.getInstance(NumberPrototype.THIRTY_TWO));
}
}
output:
Prototype.get(32):32
You can't.
The Java compiler is just providing you with a syntactical shortcut.
From the Java Tutorial:
[...] a string literal [is] a series of characters in your code that is enclosed in double quotes. Whenever it encounters a string literal in your code, the compiler creates a String object with its value
Actually this type of assignment does work for the primitive wrapper classes due to auto-boxing
Integer n = 23;
You can't since the primitive values are part of the java language, if you wanted to make a class to be "initialized" like that you should add it to the java parse or something like that.
