Copying Character array into char array

    char[] myCharArray = Arrays.stream(myCharacterArray)
            .map(ch -> ch.toString())
            .collect(Collectors.joining())
            .toCharArray();

It was fast to write. Whether it will execute fast? Unless you have a very big array or do this conversion often, you shouldn‘t need to care.

The answer by fozzybear presents a variant of the same that you may also consider.

There is method in Apache Commons Lang which does exactly what you need: http://commons.apache.org/proper/commons-lang/javadocs/api-release/org/apache/commons/lang3/ArrayUtils.html#toPrimitive-java.lang.Character:A-

public static char[] ArrayUtils.toPrimitive(Character[] array)

Technical not possible, but you might do with a lazy kind of unboxing Character to char. For instance using a Stream. (Which at the moment might even be additional overhead.)

If the Character array stems from a Collection, a List, then you just might take measures at the source. Though all will not be fast. But an array of Character is not sophisticated, like wrapping every coin in its own piece of paper.

Given a Character[] array

Character[] asciiChars = Stream.iterate(32, i -> i += 1)
                         .map(i -> Character.valueOf((char)i.intValue()))
                         .limit(95)
                         .toArray(Character[]::new);

A similar Stream-based solution to the example above, saving one mapping step, would be:

char[] chars = Stream.of(asciiChars)
               .collect(StringBuilder::new, StringBuilder::append, StringBuilder::append)
               .toString()
               .toCharArray();