| Interface | Description | 
|---|---|
| Collection<E> | The root interface in the collection hierarchy. | 
| Comparator<T> | A comparison function, which imposes a total ordering on some collection of objects. | 
| Deque<E> | A linear collection that supports element insertion and removal at both ends. | 
| Enumeration<E> | An object that implements the Enumeration interface generates a series of elements, one at a
 time. | 
| EventListener | A tagging interface that all event listener interfaces must extend. | 
| Iterator<E> | An iterator over a collection. | 
| List<E> | An ordered collection (also known as a sequence). | 
| ListIterator<E> | An iterator for lists that allows the programmer to traverse the list in either direction, modify
 the list during iteration, and obtain the iterator's current position in the list. | 
| Map<K,V> | An object that maps keys to values. | 
| Map.Entry<K,V> | A map entry (key-value pair). | 
| NavigableMap<K,V> | A  SortedMapextended with navigation methods returning the closest matches for given search targets. | 
| NavigableSet<E> | A  SortedSetextended with navigation methods reporting closest matches for given search targets. | 
| Observer | A class can implement the  Observerinterface when it wants to be informed of changes
 in observable objects. | 
| Queue<E> | A collection designed for holding elements prior to processing. | 
| RandomAccess | Marker interface used by List implementations to indicate that they support fast
 (generally constant time) random access. | 
| Set<E> | A collection that contains no duplicate elements. | 
| SortedMap<K,V> | A  Mapthat further provides a total ordering on its keys. | 
| SortedSet<E> | A  Setthat further provides a total ordering on its elements. | 
| Class | Description | 
|---|---|
| AbstractCollection<E> | This class provides a skeletal implementation of the Collection interface, to minimize
 the effort required to implement this interface. | 
| AbstractList<E> | This class provides a skeletal implementation of the  Listinterface to minimize the
 effort required to implement this interface backed by a "random access" data store (such as an
 array). | 
| AbstractMap<K,V> | This class provides a skeletal implementation of the Map interface, to minimize the
 effort required to implement this interface. | 
| AbstractMap.SimpleEntry<K,V> | An Entry maintaining a key and a value. | 
| AbstractMap.SimpleImmutableEntry<K,V> | An Entry maintaining an immutable key and value. | 
| AbstractQueue<E> | This class provides skeletal implementations of some  Queueoperations. | 
| AbstractSequentialList<E> | This class provides a skeletal implementation of the List interface to minimize the effort required to
 implement this interface backed by a "sequential access" data store (such as a linked list). | 
| AbstractSet<E> | This class provides a skeletal implementation of the Set interface to minimize the
 effort required to implement this interface. | 
| ArrayDeque<E> | Resizable-array implementation of the  Dequeinterface. | 
| ArrayList<E> | Resizable-array implementation of the List interface. | 
| Arrays | This class contains various methods for manipulating arrays (such as sorting and searching). | 
| Base64 | This class consists exclusively of static methods for obtaining encoders and decoders for the Base64 encoding scheme. | 
| Base64.Decoder | This class implements a decoder for decoding byte data using the Base64 encoding scheme as specified in RFC 4648
 and RFC 2045. | 
| Base64.Encoder | This class implements an encoder for encoding byte data using the Base64 encoding scheme as specified in RFC 4648
 and RFC 2045. | 
| BitSet | This class implements a vector of bits that grows as needed. | 
| Calendar | The  Calendarclass is an abstract class that provides methods for converting between
 a specific instant in time and a set ofcalendar fieldssuch asYEAR,MONTH,DAY_OF_MONTH,HOUR, and so on, and for
 manipulating the calendar fields, such as getting the date of the next week. | 
| Collections | This class consists exclusively of static methods that operate on or return collections. | 
| Date | The class  Daterepresents a specific instant in time, with millisecond precision. | 
| Dictionary<K,V> | The  Dictionaryclass is the abstract parent of any class, such asHashtable, which maps keys to values. | 
| EventObject | 
 The root class from which all event state objects shall be derived. | 
| Formatter | An interpreter for printf-style format strings. | 
| HashMap<K,V> | Hash table based implementation of the Map interface. | 
| HashSet<E> | This class implements the Set interface, backed by a hash table (actually a HashMap instance). | 
| Hashtable<K,V> | This class implements a hash table, which maps keys to values. | 
| LinkedList<E> | Doubly-linked list implementation of the  ListandDequeinterfaces. | 
| Objects | This class consists of  staticutility methods for operating on objects. | 
| Observable | This class represents an observable object, or "data" in the model-view paradigm. | 
| Properties | The  Propertiesclass represents a persistent set of properties. | 
| PropertyPermission | This class is for property permissions. | 
| Random | An instance of this class is used to generate a stream of pseudorandom numbers. | 
| Stack<E> | The  Stackclass represents a last-in-first-out (LIFO) stack of objects. | 
| StringTokenizer | The string tokenizer class allows an application to break a string into tokens. | 
| TimeZone | TimeZonerepresents a time zone offset, and also figures out daylight savings. | 
| TreeMap<K,V> | A Red-Black tree based  NavigableMapimplementation. | 
| TreeSet<E> | A  NavigableSetimplementation based on aTreeMap. | 
| Vector<E> | The  Vectorclass implements a growable array of objects. | 
| WeakHashMap<K,V> | Hash table based implementation of the Map interface, with weak keys. | 
| Exception | Description | 
|---|---|
| ConcurrentModificationException | This exception may be thrown by methods that have detected concurrent modification of an object
 when such modification is not permissible. | 
| DuplicateFormatFlagsException | Unchecked exception thrown when duplicate flags are provided in the format specifier. | 
| EmptyStackException | Thrown by methods in the  Stackclass to indicate that the stack is empty. | 
| FormatFlagsConversionMismatchException | Unchecked exception thrown when a conversion and flag are incompatible. | 
| FormatterClosedException | Unchecked exception thrown when the formatter has been closed. | 
| IllegalFormatConversionException | Unchecked exception thrown when the argument corresponding to the format specifier is of an incompatible type. | 
| IllegalFormatException | Unchecked exception thrown when a format string contains an illegal syntax
 or a format specifier that is incompatible with the given arguments. | 
| IllegalFormatFlagsException | Unchecked exception thrown when an illegal combination flags is given. | 
| IllegalFormatPrecisionException | Unchecked exception thrown when the precision is a negative value other than
 -1, the conversion does not support a precision, or the value is
 otherwise unsupported. | 
| IllegalFormatWidthException | Unchecked exception thrown when the format width is a negative value other
 than -1 or is otherwise unsupported. | 
| MissingFormatArgumentException | Unchecked exception thrown when there is a format specifier which does not have a corresponding argument or if an
 argument index refers to an argument that does not exist. | 
| MissingFormatWidthException | Unchecked exception thrown when the format width is required. | 
| NoSuchElementException | Thrown by the  nextElementmethod of anEnumerationto indicate that
 there are no more elements in the enumeration. | 
| UnknownFormatConversionException | Unchecked exception thrown when an unknown conversion is given. | 
| UnknownFormatFlagsException | Unchecked exception thrown when an unknown flag is given. |