@Beta
@GwtIncompatible
public final class ArbitraryInstances
extends java.lang.Object

Supplies an arbitrary "default" instance for a wide range of types, often useful in testing utilities.

Covers arrays, enums and common types defined in java.lang, java.lang.reflect, java.io, java.nio, java.math, java.util, java.util.concurrent, java.util.regex, com.google.common.base, com.google.common.collect and com.google.common.primitives. In addition, if the type exposes at least one public static final constant of the same type, one of the constants will be used; or if the class exposes a public parameter-less constructor then it will be "new"d and returned.

All default instances returned by get(java.lang.Class<T>) are generics-safe. Clients won't get type errors for using get(Comparator.class) as a Comparator<Foo>, for example. Immutable empty instances are returned for collection types; "" for string; 0 for number types; reasonable default instance for other stateless types. For mutable types, a fresh instance is created each time get() is called.