What is the equivalent of Java static methods in Kotlin?

Question

There is no static keyword in Kotlin.

What is the best way to represent a static Java method in Kotlin?

Answer 1

There is no static keyword in kotlin. kotlin docs recommends to use package-level functions if u want to follow DRY. Create a file with .kt extension and put your method in it.

package p
    fun m(){
    //fun body
    }

after compilation m will have a signature of public static final void

and

import p.m

☺

Answer 2

A. Old Java Way :

1. Declare a companion object to enclose a static method / variable

   class Foo{
   companion object {
       fun foo() = println("Foo")
       val bar ="bar"  
       }
   }
   

2. Use :

   Foo.foo()        // Outputs Foo    
   println(Foo.bar) // Outputs bar
   

---

---

B. New Kotlin way

1. Declare directly on file without class on a .kt file.

   fun foo() = println("Foo")
   val bar ="bar"
   

2. Use the methods/variables with their names. (After importing them)

   Use :

   foo()        // Outputs Foo          
   println(bar) // Outputs bar     
   

---

Answer 3

Use @JVMStatic Annotation

companion object {

    // TODO: Rename and change types and number of parameters
    @JvmStatic
    fun newInstance(param1: String, param2: String) =
            EditProfileFragment().apply {
                arguments = Bundle().apply {
                    putString(ARG_PARAM1, param1)
                    putString(ARG_PARAM2, param2)
                }
            }
}

Answer 4

Docs recommends to solve most of the needs for static functions with package-level functions. They are simply declared outside a class in a source code file. The package of a file can be specified at the beginning of a file with the package keyword.

Declaration

package foo

fun bar() = {}

Usage

import foo.bar

Alternatively

import foo.*

You can now call the function with:

bar()

or if you do not use the import keyword:

foo.bar()

If you do not specify the package the function will be accessible from the root.

If you only have experience with java, this might seem a little strange. The reason is that kotlin is not a strictly object-oriented language. You could say it supports methods outside of classes.

Edit: They have edited the documentation to no longer include the sentence about recommending package level functions. This is the original that was referred to above.

Answer 5

object objectName {
    fun funName() {

    }
}

Answer 6

Simply you need to create a companion object and put the function in it

  class UtilClass {
        companion object {
  //        @JvmStatic
            fun repeatIt5Times(str: String): String = str.repeat(5)
        }
    }

---

To invoke the method from a kotlin class:

class KotlinClass{
  fun main(args : Array<String>) { 
    UtilClass.repeatIt5Times("Hello")
  }
}

or Using import

import Packagename.UtilClass.Companion.repeatIt5Times
class KotlinClass{
  fun main(args : Array<String>) { 
     repeatIt5Times("Hello")
  }
}

---

To invoke the method from a java class:

 class JavaClass{
    public static void main(String [] args){
       UtilClass.Companion.repeatIt5Times("Hello");
    }
 }

or by adding @JvmStatic annotation to the method

class JavaClass{
   public static void main(String [] args){
     UtilClass.repeatIt5Times("Hello")
   }
}

or both by adding @JvmStatic annotation to the method and making static import in java

import static Packagename.UtilClass.repeatIt5Times
class JavaClass{
   public static void main(String [] args){
     repeatIt5Times("Hello")
   }
}