CODEWITHSUNDEEP
javaimport
Akiner Alkan
Akiner Alkan

Reputation: 6912

Grouping Imports at Java

Does Java support grouping the imports like following:

import package.{Class1,Class2}

I know that * operator imports sub packages but I want to import specific ones.

In Rust or some modern languages it is supported like following:

use package::{Class1, Class2};

Are there any alternative instead of writing each import line by line specifically like this?

import package.Class1;
import package.Class2;

Upvotes: 3

Views: 1078

Answers (3)

Andreas
Andreas

Reputation: 159135

Java Language Specification, section 7.5. Import Declarations, shows:

An import declaration allows a named type or a static member to be referred to by a simple name (§6.2) that consists of a single identifier.

[...]

  • A single-type-import declaration (§7.5.1) imports a single named type, by mentioning its canonical name (§6.7).

  • A type-import-on-demand declaration (§7.5.2) imports all the accessible types of a named type or named package as needed, by mentioning the canonical name of a type or package.

  • A single-static-import declaration (§7.5.3) imports all accessible static members with a given name from a type, by giving its canonical name.

  • A static-import-on-demand declaration (§7.5.4) imports all accessible static members of a named type as needed, by mentioning the canonical name of a type.

As you can see, it's either a single named type, or all accessible types. No syntax for a list of types.

Side note: I almost never look at the import statements of my code. I let Eclipse manage that for me (Source > Organize Imports... (Ctrl+Shift+O)), so I don't really care about having many single-type import statements. The section with the imports is collapsed anyway, so I don't even have to scroll past them. Oh the joy of using a good IDE.

Upvotes: 2

ernest_k
ernest_k

Reputation: 45329

No. Java doesn't have a construct to import a set of select classes using one statement. You either import all types from the package, or you import them one by one.

Using * lets you import all classes from the same package (not to import sub-packages, as you mentioned):

import package.*; //Both Class1 and Class2 are imported
import static package.Class1.* //All static members of Class1 are imported

The first form import package.* is usually discouraged because of the increased potential for name clashes (same class names from different packages). This is probably where import package.{Class1,Class2} would have helped, but there's no such construct in Java.

Upvotes: 1

www.hybriscx.com
www.hybriscx.com

Reputation: 1129

In java, only supported ways to import multiple classes are as follows :

A - import individual classes

import package.Class1;
import package.Class2;

B - import all classes in a package or subpackage

import package.*;
import package.subpackage.*;

Refer Oracle doc for more information : https://docs.oracle.com/javase/tutorial/java/package/usepkgs.html

Upvotes: 1

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