imports

[Lovleen Gupta]

import static java.lang.System.out;
import static java.lang.Integer.*;
 
class staticimport{
public static void main(String[] args){
    out.println(MAX_VALUE);
    out.println(toHexString(42));
}
}    

In this program -- they are importing static System.out and using only out.println..
Also, they are importing static Integer.* and using MAX_VALUE..
However, if we import staic Integer and use Integer.MAX_VALUE..why does it not work??
Please explain.

Thanks,
Lovleen.

[sharan vasandani]

its working dear

regards,
Sharan

[Vishal K Patel]

yes....its working fine...!!!

[Lovleen Gupta]

rigth you are..its working..
but my question is why will it not work if we do import static java.lang.Integer instead of java.lang.Integer.* ?

Thanks.

[Sourin K. Sen]

Just think about it. What's the purpose of a static import ? To import the static members of a particular class.

When you write

import static java.lang.Integer.*;

you are telling the compiler that you want to import all the static members of Integer class so that you can call them directly without having to write "Integer." infront of them.

But when you try to write

import static java.lang.Integer;

you are actually telling the compiler to import a static top level class & if you remember, top level classes can never be static which means that you cannot ever import a top level class which is static. But by writing the preceding you are trying to do just that & hence the compiler wont allow you to do so.

Regards,
Sourin.

[Lovleen Gupta]

Originally posted by Sourin K. Sen:
Just think about it. What's the purpose of a static import ? To import the static members of a particular class.

When you write

import static java.lang.Integer.*;

you are telling the compiler that you want to import all the static members of Integer class so that you can call them directly without having to write "Integer." infront of them.

But when you try to write

import static java.lang.Integer;

you are actually telling the compiler to import a static top level class & if you remember, top level classes can never be static which means that you cannot ever import a top level class which is static. But by writing the preceding you are trying to do just that & hence the compiler wont allow you to do so.

Regards,
Sourin.

All right, Sourin..Got your point..
But why does it then work in case of import static System.out?

[Sourin K. Sen]

That's because out is a static field in System class. Again, the static import, imports only the static members in a class, be it a field, a method or a static inner class.

If you write it this way :
import static java.lang.System.out;

it means you are telling the compiler that you want to import only the static "out" field in the System class & you dont want to import any other static member of that class.

This is just a way of importing static members individually.

[Lovleen Gupta]

All rightie..
Thanks Souren.

[Ankith suresh]

import static java.lang.System.out;
import static java.lang.Integer.*;

class staticimport11{
public static void main(String[] args){
out.println(MAX_VALUE);
out.println(toHexString(42));
}
}

For me the above code is not compiling...
I am getting the following error...help me

---------- compiler ----------
staticimport11.java:1: <identifier> expected
import static java.lang.System.out;
^
staticimport11.java:1: '.' expected
import static java.lang.System.out;
^
staticimport11.java:2: <identifier> expected
import static java.lang.Integer.*;
^
staticimport11.java:2: '.' expected
import static java.lang.Integer.*;
^
4 errors

Output completed (0 sec consumed) - Normal Termination

[Thillakan Saba]

It is working, DEAR

[Thillakan Saba]

ANS :
2147483647
2a

[Mohammed Niaz M.]

import static java.lang.System.out;
------

Im getting syntax error static 'Identifier ' expected.

[Ankith suresh]

Hi Mohammed Niaz

Only both of us getting this error!!!
anybody else..???
Please help us..
Is it version problem???

[anil kumar]

Hi

If its a version problem we will get the error like this

C:\practice\basics>javac -source 1.4 static1.java
static1.java:1: static import declarations are not supported in -source 1.4
(try -source 1.5 to enable static import declarations)
import static java.lang.System.out;
^
static1.java:4: variable-arity methods are not supported in -source 1.4
(try -source 1.5 to enable variable-arity methods)
public static void main(String... args)
^
2 errors


Thanks

Anil Kumar

[thiagarajan saravanakumar]

yes it is working fine and i got output as
2147483647
2a
it is better to check verison ,
have you installed jdk 1.5 or not??

[Ankith suresh]

Hi thiagarajan

I am using jdk1.4

[Henry Wong]

Originally posted by Ankith suresh:
Hi thiagarajan

I am using jdk1.4

Static imports were added in Java 5.0.

Henry