Scala 3/API/scala.collection/JavaConverters

JavaConverters

@deprecated("Use `scala.jdk.CollectionConverters` instead", "2.13.0") object JavaConverters extends AsJavaConverters with AsScalaConverters

A variety of decorators that enable converting between Scala and Java collections using extension methods, asScala and asJava.

A variety of decorators that enable converting between Scala and Java collections using extension methods, asScala and asJava.

The extension methods return adapters for the corresponding API.

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.collection.JavaConverters._

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)

Alternatively, the conversion methods have descriptive names and can be invoked explicitly.

scala> val vs = java.util.Arrays.asList("hi", "bye")
vs: java.util.List[String] = [hi, bye]

scala> val ss = asScalaIterator(vs.iterator)
ss: Iterator[String] = 

scala> .toList
res0: List[String] = List(hi, bye)

scala> val ss = asScalaBuffer(vs)
ss: scala.collection.mutable.Buffer[String] = Buffer(hi, bye)
Deprecated
class Object
trait Matchable
class Any

Type members

Classlikes

class AsJava[A](op: => A)

Generic class containing the asJava converter method

Generic class containing the asJava converter method

class AsJavaCollection[A](i: Iterable[A])

Generic class containing the asJavaCollection converter method

Generic class containing the asJavaCollection converter method

class AsJavaDictionary[K, V](m: Map[K, V])

Generic class containing the asJavaDictionary converter method

Generic class containing the asJavaDictionary converter method

class AsJavaEnumeration[A](i: Iterator[A])

Generic class containing the asJavaEnumeration converter method

Generic class containing the asJavaEnumeration converter method

class AsScala[A](op: => A)

Generic class containing the asScala converter method

Generic class containing the asScala converter method

Value members

Deprecated methods

@deprecated("Use `asJava` instead", "2.13.0")
def asJavaIterable[A](i: Iterable[A]): Iterable[A]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def asJavaIterator[A](i: Iterator[A]): Iterator[A]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def asScalaBuffer[A](l: List[A]): Buffer[A]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def asScalaIterator[A](i: Iterator[A]): Iterator[A]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def asScalaSet[A](s: Set[A]): Set[A]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def bufferAsJavaList[A](b: Buffer[A]): List[A]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def collectionAsScalaIterable[A](i: Collection[A]): Iterable[A]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def dictionaryAsScalaMap[A, B](p: Dictionary[A, B]): Map[A, B]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def enumerationAsScalaIterator[A](i: Enumeration[A]): Iterator[A]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def iterableAsScalaIterable[A](i: Iterable[A]): Iterable[A]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def mapAsJavaConcurrentMap[K, V](m: Map[K, V]): ConcurrentMap[K, V]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def mapAsJavaMap[K, V](m: Map[K, V]): Map[K, V]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def mapAsScalaConcurrentMap[A, B](m: ConcurrentMap[A, B]): Map[A, B]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def mapAsScalaMap[A, B](m: Map[A, B]): Map[A, B]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def mutableMapAsJavaMap[K, V](m: Map[K, V]): Map[K, V]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def mutableSeqAsJavaList[A](s: Seq[A]): List[A]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def mutableSetAsJavaSet[A](s: Set[A]): Set[A]
Deprecated
@deprecated("Use `asScala` instead", "2.13.0")
def propertiesAsScalaMap(p: Properties): Map[String, String]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def seqAsJavaList[A](s: Seq[A]): List[A]
Deprecated
@deprecated("Use `asJava` instead", "2.13.0")
def setAsJavaSet[A](s: Set[A]): Set[A]
Deprecated

Inherited methods

def asJava[K, V](m: Map[K, V]): ConcurrentMap[K, V]

Converts a Scala mutable concurrent.Map to a Java ConcurrentMap.

Converts a Scala mutable concurrent.Map to a Java ConcurrentMap.

The returned Java ConcurrentMap is backed by the provided Scala concurrent.Map and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala concurrent.Map was previously obtained from an implicit or explicit call of asScala then the original Java ConcurrentMap will be returned.

Value Params
m

The Scala concurrent.Map to be converted.

Returns

A Java ConcurrentMap view of the argument.

Inherited from
AsJavaConverters
def asJava[K, V](m: Map[K, V]): Map[K, V]

Converts a Scala Map to a Java Map.

Converts a Scala Map to a Java Map.

The returned Java Map is backed by the provided Scala Map and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Map was previously obtained from an implicit or explicit call of asScala then the original Java Map will be returned.

Value Params
m

The Scala Map to be converted.

Returns

A Java Map view of the argument.

Inherited from
AsJavaConverters
def asJava[K, V](m: Map[K, V]): Map[K, V]

Converts a Scala mutable Map to a Java Map.

Converts a Scala mutable Map to a Java Map.

The returned Java Map is backed by the provided Scala Map and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Map was previously obtained from an implicit or explicit call of asScala then the original Java Map will be returned.

Value Params
m

The Scala mutable Map to be converted.

Returns

A Java Map view of the argument.

Inherited from
AsJavaConverters
def asJava[A](s: Set[A]): Set[A]

Converts a Scala Set to a Java Set.

Converts a Scala Set to a Java Set.

The returned Java Set is backed by the provided Scala Set and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Set was previously obtained from an implicit or explicit call of asScala then the original Java Set will be returned.

Value Params
s

The Scala Set to be converted.

Returns

A Java Set view of the argument.

Inherited from
AsJavaConverters
def asJava[A](s: Set[A]): Set[A]

Converts a Scala mutable Set to a Java Set.

Converts a Scala mutable Set to a Java Set.

The returned Java Set is backed by the provided Scala Set and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Set was previously obtained from an implicit or explicit call of asScala then the original Java Set will be returned.

Value Params
s

The Scala mutable Set to be converted.

Returns

A Java Set view of the argument.

Inherited from
AsJavaConverters
def asJava[A](s: Seq[A]): List[A]

Converts a Scala Seq to a Java List.

Converts a Scala Seq to a Java List.

The returned Java List is backed by the provided Scala Seq and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Seq was previously obtained from an implicit or explicit call of asScala then the original Java List will be returned.

Value Params
s

The Scala Seq to be converted.

Returns

A Java List view of the argument.

Inherited from
AsJavaConverters
def asJava[A](s: Seq[A]): List[A]

Converts a Scala mutable Seq to a Java List.

Converts a Scala mutable Seq to a Java List.

The returned Java List is backed by the provided Scala Seq and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Seq was previously obtained from an implicit or explicit call of asScala then the original Java List will be returned.

Value Params
s

The Scala Seq to be converted.

Returns

A Java List view of the argument.

Inherited from
AsJavaConverters
def asJava[A](b: Buffer[A]): List[A]

Converts a Scala mutable Buffer to a Java List.

Converts a Scala mutable Buffer to a Java List.

The returned Java List is backed by the provided Scala Buffer and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Buffer was previously obtained from an implicit or explicit call of asScala then the original Java List will be returned.

Value Params
b

The Scala Buffer to be converted.

Returns

A Java List view of the argument.

Inherited from
AsJavaConverters
def asJava[A](i: Iterable[A]): Iterable[A]

Converts a Scala Iterable to a Java Iterable.

Converts a Scala Iterable to a Java Iterable.

The returned Java Iterable is backed by the provided Scala Iterable and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Iterable was previously obtained from an implicit or explicit call of asScala then the original Java Iterable will be returned.

Value Params
i

The Scala Iterable to be converted.

Returns

A Java Iterable view of the argument.

Inherited from
AsJavaConverters
def asJava[A](i: Iterator[A]): Iterator[A]

Converts a Scala Iterator to a Java Iterator.

Converts a Scala Iterator to a Java Iterator.

The returned Java Iterator is backed by the provided Scala Iterator and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Iterator was previously obtained from an implicit or explicit call of asScala then the original Java Iterator will be returned.

Value Params
i

The Scala Iterator to be converted.

Returns

A Java Iterator view of the argument.

Inherited from
AsJavaConverters
def asJavaCollection[A](i: Iterable[A]): Collection[A]

Converts a Scala Iterable to an immutable Java Collection.

Converts a Scala Iterable to an immutable Java Collection.

If the Scala Iterable was previously obtained from an implicit or explicit call of asScala then the original Java Collection will be returned.

Value Params
i

The Scala Iterable to be converted.

Returns

A Java Collection view of the argument.

Inherited from
AsJavaConverters
def asJavaDictionary[K, V](m: Map[K, V]): Dictionary[K, V]

Converts a Scala mutable Map to a Java Dictionary.

Converts a Scala mutable Map to a Java Dictionary.

The returned Java Dictionary is backed by the provided Scala Dictionary and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Map was previously obtained from an implicit or explicit call of asScala then the original Java Dictionary will be returned.

Value Params
m

The Scala Map to be converted.

Returns

A Java Dictionary view of the argument.

Inherited from
AsJavaConverters
def asJavaEnumeration[A](i: Iterator[A]): Enumeration[A]

Converts a Scala Iterator to a Java Enumeration.

Converts a Scala Iterator to a Java Enumeration.

The returned Java Enumeration is backed by the provided Scala Iterator and any side-effects of using it via the Java interface will be visible via the Scala interface and vice versa.

If the Scala Iterator was previously obtained from an implicit or explicit call of asScala then the original Java Enumeration will be returned.

Value Params
i

The Scala Iterator to be converted.

Returns

A Java Enumeration view of the argument.

Inherited from
AsJavaConverters
def asScala(p: Properties): Map[String, String]

Converts a Java Properties to a Scala mutable Map[String, String].

Converts a Java Properties to a Scala mutable Map[String, String].

The returned Scala Map[String, String] is backed by the provided Java Properties and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

Value Params
p

The Java Properties to be converted.

Returns

A Scala mutable Map[String, String] view of the argument.

Inherited from
AsScalaConverters
def asScala[A, B](d: Dictionary[A, B]): Map[A, B]

Converts a Java Dictionary to a Scala mutable Map.

Converts a Java Dictionary to a Scala mutable Map.

The returned Scala Map is backed by the provided Java Dictionary and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java Dictionary was previously obtained from an implicit or explicit call of asJavaDictionary then the original Scala Map will be returned.

Value Params
d

The Java Dictionary to be converted.

Returns

A Scala mutable Map view of the argument.

Inherited from
AsScalaConverters
def asScala[A, B](m: ConcurrentMap[A, B]): Map[A, B]

Converts a Java ConcurrentMap to a Scala mutable ConcurrentMap.

Converts a Java ConcurrentMap to a Scala mutable ConcurrentMap.

The returned Scala ConcurrentMap is backed by the provided Java ConcurrentMap and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java ConcurrentMap was previously obtained from an implicit or explicit call of asJava then the original Scala ConcurrentMap will be returned.

Value Params
m

The Java ConcurrentMap to be converted.

Returns

A Scala mutable ConcurrentMap view of the argument.

Inherited from
AsScalaConverters
def asScala[A, B](m: Map[A, B]): Map[A, B]

Converts a Java Map to a Scala mutable Map.

Converts a Java Map to a Scala mutable Map.

The returned Scala Map is backed by the provided Java Map and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java Map was previously obtained from an implicit or explicit call of asJava then the original Scala Map will be returned.

If the wrapped map is synchronized (e.g. from java.util.Collections.synchronizedMap), it is your responsibility to wrap all non-atomic operations with underlying.synchronized. This includes get, as java.util.Map's API does not allow for an atomic get when null values may be present.

Value Params
m

The Java Map to be converted.

Returns

A Scala mutable Map view of the argument.

Inherited from
AsScalaConverters
def asScala[A](s: Set[A]): Set[A]

Converts a Java Set to a Scala mutable Set.

Converts a Java Set to a Scala mutable Set.

The returned Scala Set is backed by the provided Java Set and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java Set was previously obtained from an implicit or explicit call of asJava then the original Scala Set will be returned.

Value Params
s

The Java Set to be converted.

Returns

A Scala mutable Set view of the argument.

Inherited from
AsScalaConverters
def asScala[A](l: List[A]): Buffer[A]

Converts a Java List to a Scala mutable Buffer.

Converts a Java List to a Scala mutable Buffer.

The returned Scala Buffer is backed by the provided Java List and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java List was previously obtained from an implicit or explicit call of asJava then the original Scala Buffer will be returned.

Value Params
l

The Java List to be converted.

Returns

A Scala mutable Buffer view of the argument.

Inherited from
AsScalaConverters
def asScala[A](c: Collection[A]): Iterable[A]

Converts a Java Collection to a Scala Iterable.

Converts a Java Collection to a Scala Iterable.

If the Java Collection was previously obtained from an implicit or explicit call of asJavaCollection then the original Scala Iterable will be returned.

Value Params
c

The Java Collection to be converted.

Returns

A Scala Iterable view of the argument.

Inherited from
AsScalaConverters
def asScala[A](i: Iterable[A]): Iterable[A]

Converts a Java Iterable to a Scala Iterable.

Converts a Java Iterable to a Scala Iterable.

The returned Scala Iterable is backed by the provided Java Iterable and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java Iterable was previously obtained from an implicit or explicit call of asJava then the original Scala Iterable will be returned.

Value Params
i

The Java Iterable to be converted.

Returns

A Scala Iterable view of the argument.

Inherited from
AsScalaConverters
def asScala[A](e: Enumeration[A]): Iterator[A]

Converts a Java Enumeration to a Scala Iterator.

Converts a Java Enumeration to a Scala Iterator.

The returned Scala Iterator is backed by the provided Java Enumeration and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java Enumeration was previously obtained from an implicit or explicit call of asJavaEnumeration then the original Scala Iterator will be returned.

Value Params
e

The Java Enumeration to be converted.

Returns

A Scala Iterator view of the argument.

Inherited from
AsScalaConverters
def asScala[A](i: Iterator[A]): Iterator[A]

Converts a Java Iterator to a Scala Iterator.

Converts a Java Iterator to a Scala Iterator.

The returned Scala Iterator is backed by the provided Java Iterator and any side-effects of using it via the Scala interface will be visible via the Java interface and vice versa.

If the Java Iterator was previously obtained from an implicit or explicit call of asJava then the original Scala Iterator will be returned.

Value Params
i

The Java Iterator to be converted.

Returns

A Scala Iterator view of the argument.

Inherited from
AsScalaConverters

Implicits

Implicits

implicit def asJavaCollectionConverter[A](i: Iterable[A]): AsJavaCollection[A]

Adds an asJavaCollection method that implicitly converts a Scala Iterable to an immutable Java Collection.

Adds an asJavaCollection method that implicitly converts a Scala Iterable to an immutable Java Collection.

See also
implicit def asJavaDictionaryConverter[K, V](m: Map[K, V]): AsJavaDictionary[K, V]

Adds an asJavaDictionary method that implicitly converts a Scala mutable Map to a Java Dictionary.

Adds an asJavaDictionary method that implicitly converts a Scala mutable Map to a Java Dictionary.

See also
implicit def asJavaEnumerationConverter[A](i: Iterator[A]): AsJavaEnumeration[A]

Adds an asJavaEnumeration method that implicitly converts a Scala Iterator to a Java Enumeration.

Adds an asJavaEnumeration method that implicitly converts a Scala Iterator to a Java Enumeration.

See also
implicit def asJavaIterableConverter[A](i: Iterable[A]): AsJava[Iterable[A]]

Adds an asJava method that implicitly converts a Scala Iterable to a Java Iterable.

Adds an asJava method that implicitly converts a Scala Iterable to a Java Iterable.

See also
implicit def asJavaIteratorConverter[A](i: Iterator[A]): AsJava[Iterator[A]]

Adds an asJava method that implicitly converts a Scala Iterator to a Java Iterator.

Adds an asJava method that implicitly converts a Scala Iterator to a Java Iterator.

See also
implicit def asScalaBufferConverter[A](l: List[A]): AsScala[Buffer[A]]

Adds an asScala method that implicitly converts a Java List to a Scala mutable Buffer.

Adds an asScala method that implicitly converts a Java List to a Scala mutable Buffer.

See also
implicit def asScalaIteratorConverter[A](i: Iterator[A]): AsScala[Iterator[A]]

Adds an asScala method that implicitly converts a Java Iterator to a Scala Iterator.

Adds an asScala method that implicitly converts a Java Iterator to a Scala Iterator.

See also
implicit def asScalaSetConverter[A](s: Set[A]): AsScala[Set[A]]

Adds an asScala method that implicitly converts a Java Set to a Scala mutable Set.

Adds an asScala method that implicitly converts a Java Set to a Scala mutable Set.

See also
implicit def bufferAsJavaListConverter[A](b: Buffer[A]): AsJava[List[A]]

Adds an asJava method that implicitly converts a Scala mutable Buffer to a Java List.

Adds an asJava method that implicitly converts a Scala mutable Buffer to a Java List.

See also
implicit def collectionAsScalaIterableConverter[A](i: Collection[A]): AsScala[Iterable[A]]

Adds an asScala method that implicitly converts a Java Collection to an Scala Iterable.

Adds an asScala method that implicitly converts a Java Collection to an Scala Iterable.

See also
implicit def dictionaryAsScalaMapConverter[K, V](p: Dictionary[K, V]): AsScala[Map[K, V]]

Adds an asScala method that implicitly converts a Java Dictionary to a Scala mutable Map.

Adds an asScala method that implicitly converts a Java Dictionary to a Scala mutable Map.

See also
implicit def enumerationAsScalaIteratorConverter[A](i: Enumeration[A]): AsScala[Iterator[A]]

Adds an asScala method that implicitly converts a Java Enumeration to a Scala Iterator.

Adds an asScala method that implicitly converts a Java Enumeration to a Scala Iterator.

See also
implicit def iterableAsScalaIterableConverter[A](i: Iterable[A]): AsScala[Iterable[A]]

Adds an asScala method that implicitly converts a Java Iterable to a Scala Iterable.

Adds an asScala method that implicitly converts a Java Iterable to a Scala Iterable.

See also
implicit def mapAsJavaConcurrentMapConverter[K, V](m: Map[K, V]): AsJava[ConcurrentMap[K, V]]

Adds an asJava method that implicitly converts a Scala mutable concurrent.Map to a Java ConcurrentMap.

Adds an asJava method that implicitly converts a Scala mutable concurrent.Map to a Java ConcurrentMap.

See also
implicit def mapAsJavaMapConverter[K, V](m: Map[K, V]): AsJava[Map[K, V]]

Adds an asJava method that implicitly converts a Scala Map to a Java Map.

Adds an asJava method that implicitly converts a Scala Map to a Java Map.

See also
implicit def mapAsScalaConcurrentMapConverter[K, V](m: ConcurrentMap[K, V]): AsScala[Map[K, V]]

Adds an asScala method that implicitly converts a Java ConcurrentMap to a Scala mutable concurrent.Map.

Adds an asScala method that implicitly converts a Java ConcurrentMap to a Scala mutable concurrent.Map.

See also
implicit def mapAsScalaMapConverter[K, V](m: Map[K, V]): AsScala[Map[K, V]]

Adds an asScala method that implicitly converts a Java Map to a Scala mutable Map.

Adds an asScala method that implicitly converts a Java Map to a Scala mutable Map.

See also
implicit def mutableMapAsJavaMapConverter[K, V](m: Map[K, V]): AsJava[Map[K, V]]

Adds an asJava method that implicitly converts a Scala mutable Map to a Java Map.

Adds an asJava method that implicitly converts a Scala mutable Map to a Java Map.

See also
implicit def mutableSeqAsJavaListConverter[A](b: Seq[A]): AsJava[List[A]]

Adds an asJava method that implicitly converts a Scala mutable Seq to a Java List.

Adds an asJava method that implicitly converts a Scala mutable Seq to a Java List.

See also
implicit def mutableSetAsJavaSetConverter[A](s: Set[A]): AsJava[Set[A]]

Adds an asJava method that implicitly converts a Scala mutable Set to a Java Set.

Adds an asJava method that implicitly converts a Scala mutable Set to a Java Set.

See also
implicit def propertiesAsScalaMapConverter(p: Properties): AsScala[Map[String, String]]

Adds an asScala method that implicitly converts a Java Properties to a Scala mutable Map[String, String].

Adds an asScala method that implicitly converts a Java Properties to a Scala mutable Map[String, String].

See also
implicit def seqAsJavaListConverter[A](b: Seq[A]): AsJava[List[A]]

Adds an asJava method that implicitly converts a Scala Seq to a Java List.

Adds an asJava method that implicitly converts a Scala Seq to a Java List.

See also
implicit def setAsJavaSetConverter[A](s: Set[A]): AsJava[Set[A]]

Adds an asJava method that implicitly converts a Scala Set to a Java Set.

Adds an asJava method that implicitly converts a Scala Set to a Java Set.

See also