Utility method for wrapping an object in a collection

Question

I\'m looking for a static method in the Java core libraries or some other commonly used dependency — preferably one of Apache — that does the following:

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Answer 1

Here are some efficient ways to wrap Java object(s) in List, as of Java 8.

Collections.singletonList: Single item, immutable, since 1.3.
Collections.singletonList( object )
High performance backed by internal class.

Collections.nCopies: One object, zero to many items, immutable, since 1.2.
Collections.nCopies( number_of_copy, object )
High performance backed by internal class. All items point to same object.

Array.asList: Any number of objects, size immutable (individual elements mutable), since 1.2.
Arrays.asList( object1, object2, object3 )
Backed by internal class. Items are converted to array at compile time and this array directly backs the List.

new ArrayList(Collection): Any number of objects, mutable, since 1.2
new ArrayList<>( Arrays.asList( object1, object2, object3 ) )
The ArrayList is created with an array clone and an array copy, and so does not use any loops.