Guava Joiner: Converting an Iterable into a String

Guava's Joiner makes it really easy to convert an Iterable into a String, so you no longer have to iterate over it and build the String manually. Here is an example:

// joining a list
final List<String> fruits = Lists.newArrayList("apple", "banana", null, "cherry");
System.out.println(Joiner.on(", ").skipNulls().join(fruits));

// joining a map
final Map<String, Integer> people = ImmutableMap.of("Alice", 21, "Bob", 19);
System.out.println(Joiner.on("\n").withKeyValueSeparator(": ").join(people));

prints:

apple, banana, cherry
Alice: 21
Bob: 19