Generic

[meeta gaur]

Synchronization Wrappers

The synchronization wrappers add automatic synchronization (thread-safety) to an arbitrary collection. Each of the six core collection interfaces — Collection, Set, List, Map, SortedSet, and SortedMap — has one static factory method.

public static <T> Collection<T> synchronizedCollection(Collection<T> c);
public static <T> Set<T> synchronizedSet(Set<T> s);
public static <T> List<T> synchronizedList(List<T> list);
public static <K,V> Map<K,V> synchronizedMap(Map<K,V> m);
public static <T> SortedSet<T> synchronizedSortedSet(SortedSet<T> s);
public static <K,V> SortedMap<K,V> synchronizedSortedMap(SortedMap<K,V> m);

I'm not getting these <T>.....<T> two times thing, what is this ?

[Jesper de Jong]

These are methods with type parameters. The first <T> is to indicate that the method has a type parameter named T, and the subsequent <T>s are places where the type parameter is used.