CODEWITHSUNDEEP
javacompilation
Aamir
Aamir

Reputation: 2424

Static Imports in Java

import static java.lang.Integer.*;
import static java.lang.Long.*;

public class StaticImortError  {

         public static void main(String args []) {
                 System.out.println(MAX_VALUE);
             }

}

Can anybody please explain why this program is showing compile time error, if I tried to use imports like import static java.lang.Integer.*; import static java.lang.Long.MAX_VALUE;, it ran fine and as expected displayed the maximum value of long data types, but with the above imports its showing error.

Upvotes: 1

Views: 3161

Answers (3)

Adam Arold
Adam Arold

Reputation: 30528

The problem is that you must explicitly state what to import in this case since both classes have a MAX_VALUE constant.

If you open the source code you'll see.

Since you can't assign an alias in java you are stuck with using Integer.MAX_VALUE/Long.MAX_VALUE.

Just a side note: I do not suggest a static import for Integer.MAX_VALUE (nor Long.MAX_VALUE) because if you have a rather big class and in the middle you reference MAX_VALUE then someone in the future will scratch his head asking "Whose max value are we talking about?"

Upvotes: 7

Andres
Andres

Reputation: 10707

You're importing MAX_VALUE twice.

It's included both on java.lang.Integer.*; and java.lang.Long.*;

Upvotes: 4

willeM_ Van Onsem
willeM_ Van Onsem

Reputation: 476493

In that case you import the static methods and fields associated with the given class.

For instance the Assert class contains a lot of methods like assertEquals.

Instead of writing each time Assert.assertEquals, you can write

import static org.junit.Assert.*;

and then use assertEquals in your code.

The reason why this doesn't work is because a call to MAX_VALUE is ambiguous between Long.MAX_VALUE and Integer.MAX_VALUE

Upvotes: 0

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