import

Learn to import packages with import.

import: Bringing in

An import declaration makes a class or function from another namespace available in the file. The declaration goes after package and before any definitions. The imported type can be used by its simple name.

package com.example.app

import java.io.File

fun main() {
    val f = File("record.txt")
}

Here java.io.File is imported; now it can be written short as File. It is also possible to write the fully qualified name: java.io.File("record.txt"). But this is long and hard to read; import is preferred.

Wildcard import

To import all types in a namespace, write import package.*. This is called a wildcard import. It is practical when many types are needed; however it can increase the risk of name clashes.

import java.io.*   // File, BufferedReader, InputStream etc.
import kotlinx.coroutines.flow.*

Wildcards shorten the code but can make it unclear which type comes from where. IDEs usually suggest single imports; this is clearer and more traceable. If two types with the same simple name are imported from different namespaces, one must be imported with an alias.

Exercise Import File and use it

At the top write package com.example.app. Then add the line import java.io.File. In main create a File with val f = File("kayit.txt") and print it with println(f) (File toString returns the path).

Show example solution

package com.example.app

import java.io.File

fun main() {
    val f = File("kayit.txt")
    println(f)
}

Test yourself

Import a class
```
____ java.io.File
```
Show answer
```
import java.io.File
```
Match the import concepts

import java.io.File

Single type
import kotlinx.*

Wildcard
simple name

Short name
fully qualified

Full path
What does import java.io.File do?
- Defines a new File class
- Renames the package
- Creates a File instance
- Makes File usable by its simple name
Show answer

Makes File usable by its simple name — import makes File usable by its simple name.

Next lesson: internal

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