A set of adaptors for types belonging to the Java language or Java SDK. Includes:

• a set of functions for converting between Ceylon's Array class and Java array types, for example, javaIntArray, javaFloatArray, javaByteArray, javaBooleanArray, javaObjectArray, and javaStringArray,
• classes adapting Java collection types to Ceylon collection interfaces: CeylonList, CeylonSet, CeylonMap,
• classes adapting Ceylon collection types to Java collection interfaces: JavaList, JavaSet, JavaMap, and
• CeylonIterable and JavaIterable which adapt between Java's [[java.lang::Iterable]] interface and Ceylon's Iterable interface,
• CeylonStringIterable, CeylonIntegerIterable, CeylonFloatIterable, CeylonByteIterable, and CeylonBooleanIterable, which adapt Java [[java.lang::Iterable]]s of primitive types,
• JavaRunnable and JavaThread which adapt Ceylon functions to Java's [[java.lang::Runnable]] and [[java.lang::Thread]], and
• JavaCloseable and CeylonDestroyable which adapt between [[java.lang::AutoCloseable]] and Destroyable.

In addition, the functions javaClass and javaClassFromInstance allow Ceylon programs to obtain an instance of [[java.lang::Class]].