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scala-library-sjs/scala/scala.jdk/CollectionConverters

CollectionConverters

scala.jdk.CollectionConverters
object CollectionConverters extends AsJavaExtensions, AsScalaExtensions

This object provides extension methods that convert between Scala and Java collections.

When writing Java code, use the explicit conversion methods defined in javaapi.CollectionConverters instead.

Note: to create Java Streams that operate on Scala collections (sequentially or in parallel), use StreamConverters.

 import scala.jdk.CollectionConverters._
 val s: java.util.Set[String] = Set("one", "two").asJava

The conversions return adapters for the corresponding API, i.e., the collections are wrapped, not copied. Changes to the original collection are reflected in the view, and vice versa:

 scala> import scala.jdk.CollectionConverters._

 scala> val s = collection.mutable.Set("one")
 s: scala.collection.mutable.Set[String] = HashSet(one)

 scala> val js = s.asJava
 js: java.util.Set[String] = [one]

 scala> js.add("two")

 scala> s
 res2: scala.collection.mutable.Set[String] = HashSet(two, one)

The following conversions are supported via asScala and asJava:

 scala.collection.Iterable       <=> java.lang.Iterable
 scala.collection.Iterator       <=> java.util.Iterator
 scala.collection.mutable.Buffer <=> java.util.List
 scala.collection.mutable.Set    <=> java.util.Set
 scala.collection.mutable.Map    <=> java.util.Map
 scala.collection.concurrent.Map <=> java.util.concurrent.ConcurrentMap

The following conversions are supported via asScala and through specially-named extension methods to convert to Java collections, as shown:

 scala.collection.Iterable    <=> java.util.Collection   (via asJavaCollection)
 scala.collection.Iterator    <=> java.util.Enumeration  (via asJavaEnumeration)
 scala.collection.mutable.Map <=> java.util.Dictionary   (via asJavaDictionary)

In addition, the following one-way conversions are provided via asJava:

 scala.collection.Seq         => java.util.List
 scala.collection.mutable.Seq => java.util.List
 scala.collection.Set         => java.util.Set
 scala.collection.Map         => java.util.Map

The following one way conversion is provided via asScala:

 java.util.Properties => scala.collection.mutable.Map

In all cases, converting from a source type to a target type and back again will return the original source object. For example:

 import scala.jdk.CollectionConverters._

 val source = new scala.collection.mutable.ListBuffer[Int]
 val target: java.util.List[Int] = source.asJava
 val other: scala.collection.mutable.Buffer[Int] = target.asScala
 assert(source eq other)

Attributes

Graph
Supertypes
class Object
trait Matchable
class Any
Self type

Members list

Type members

Inherited classlikes

implicit class BufferHasAsJava[A](b: Buffer[A])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class CollectionHasAsScala[A](c: Collection[A])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class ConcurrentMapHasAsJava[K, V](m: Map[K, V])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class ConcurrentMapHasAsScala[K, V](m: ConcurrentMap[K, V])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class DictionaryHasAsScala[K, V](d: Dictionary[K, V])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class EnumerationHasAsScala[A](e: Enumeration[A])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class IterableHasAsJava[A](i: Iterable[A])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class IterableHasAsScala[A](i: Iterable[A])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class IteratorHasAsJava[A](i: Iterator[A])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class IteratorHasAsScala[A](i: Iterator[A])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class ListHasAsScala[A](l: List[A])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class MapHasAsJava[K, V](m: Map[K, V])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class MapHasAsScala[K, V](m: Map[K, V])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class MutableMapHasAsJava[K, V](m: Map[K, V])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class MutableSeqHasAsJava[A](s: Seq[A])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class MutableSetHasAsJava[A](s: Set[A])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class PropertiesHasAsScala(i: Properties)

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class SeqHasAsJava[A](s: Seq[A])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class SetHasAsJava[A](s: Set[A])

Attributes

Inherited from:
AsJavaExtensions
Supertypes
class Object
trait Matchable
class Any
implicit class SetHasAsScala[A](s: Set[A])

Attributes

Inherited from:
AsScalaExtensions
Supertypes
class Object
trait Matchable
class Any

Implicits

Inherited implicits

implicit def BufferHasAsJava[A](b: Buffer[A]): BufferHasAsJava[A]

Attributes

Inherited from:
AsJavaExtensions
implicit def CollectionHasAsScala[A](c: Collection[A]): CollectionHasAsScala[A]

Attributes

Inherited from:
AsScalaExtensions
implicit def ConcurrentMapHasAsJava[K, V](m: Map[K, V]): ConcurrentMapHasAsJava[K, V]

Attributes

Inherited from:
AsJavaExtensions
implicit def ConcurrentMapHasAsScala[K, V](m: ConcurrentMap[K, V]): ConcurrentMapHasAsScala[K, V]

Attributes

Inherited from:
AsScalaExtensions
implicit def DictionaryHasAsScala[K, V](d: Dictionary[K, V]): DictionaryHasAsScala[K, V]

Attributes

Inherited from:
AsScalaExtensions
implicit def EnumerationHasAsScala[A](e: Enumeration[A]): EnumerationHasAsScala[A]

Attributes

Inherited from:
AsScalaExtensions
implicit def IterableHasAsJava[A](i: Iterable[A]): IterableHasAsJava[A]

Attributes

Inherited from:
AsJavaExtensions
implicit def IterableHasAsScala[A](i: Iterable[A]): IterableHasAsScala[A]

Attributes

Inherited from:
AsScalaExtensions
implicit def IteratorHasAsJava[A](i: Iterator[A]): IteratorHasAsJava[A]

Attributes

Inherited from:
AsJavaExtensions
implicit def IteratorHasAsScala[A](i: Iterator[A]): IteratorHasAsScala[A]

Attributes

Inherited from:
AsScalaExtensions
implicit def ListHasAsScala[A](l: List[A]): ListHasAsScala[A]

Attributes

Inherited from:
AsScalaExtensions
implicit def MapHasAsJava[K, V](m: Map[K, V]): MapHasAsJava[K, V]

Attributes

Inherited from:
AsJavaExtensions
implicit def MapHasAsScala[K, V](m: Map[K, V]): MapHasAsScala[K, V]

Attributes

Inherited from:
AsScalaExtensions
implicit def MutableMapHasAsJava[K, V](m: Map[K, V]): MutableMapHasAsJava[K, V]

Attributes

Inherited from:
AsJavaExtensions
implicit def MutableSeqHasAsJava[A](s: Seq[A]): MutableSeqHasAsJava[A]

Attributes

Inherited from:
AsJavaExtensions
implicit def MutableSetHasAsJava[A](s: Set[A]): MutableSetHasAsJava[A]

Attributes

Inherited from:
AsJavaExtensions
implicit def PropertiesHasAsScala(i: Properties): PropertiesHasAsScala

Attributes

Inherited from:
AsScalaExtensions
implicit def SeqHasAsJava[A](s: Seq[A]): SeqHasAsJava[A]

Attributes

Inherited from:
AsJavaExtensions
implicit def SetHasAsJava[A](s: Set[A]): SetHasAsJava[A]

Attributes

Inherited from:
AsJavaExtensions
implicit def SetHasAsScala[A](s: Set[A]): SetHasAsScala[A]

Attributes

Inherited from:
AsScalaExtensions
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Copyright (c) 2002-2025, LAMP/EPFL
Copyright (c) 2002-2025, LAMP/EPFL