import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.Deque; import java.util.EnumMap; import java.util.EnumSet; import java.util.Enumeration; import java.util.HashMap; import java.util.HashSet; import java.util.Hashtable; import java.util.Iterator; import java.util.LinkedHashSet; import java.util.LinkedList; import java.util.List; import java.util.ListIterator; import java.util.Map; import java.util.NavigableMap; import java.util.NavigableSet; import java.util.PriorityQueue; import java.util.Queue; import java.util.Set; import java.util.SortedMap; import java.util.SortedSet; import java.util.Stack; import java.util.TreeMap; import java.util.TreeSet; import java.util.Vector; enum Day{ SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY; } public class Main{ public static void main(String args[]) { //arrayCollection(); //vectorCollection(); //hashTableCollection(); //enumarationsDemo(); //iterationsDemo(); //listIteratorDemo(); //loopingIterations(); //listPositionOperations(); //listSearchOperations(); //arrayListDemo(); //linkedListDemo(); //vectorDemo(); //stackDemo(); //setDemo(); //hashSetDemo(); //linkedHashSetDemo(); //treeSetDemo(); //sortedSetDemo(); //navigableSetDemo(); //enumSetDemo(); //sortedMapDemo(); //navigableMapDemo(); //hashMapDemo(); mapEntry(); //enumMapDemo(); //queueDemo(); //priorityQueueDemo(); //dequeDemo(); //collectionsClassDemo(); } public static void collectionsClassDemo() { ArrayList defList= new ArrayList(); defList.add("Stack"); defList.add("Queue"); defList.add("Heap"); defList.add("Hashing"); defList.add("Graph"); defList.add("Array"); defList.add("Matrix"); System.out.println("Original list: "+defList); //prints [Stack, Queue, Heap, Hashing, Graph, Array, Matrix] Collections.swap(defList, 3, 4); //Swaps the elements at the specified positions in the specified list. System.out.println("Swapped list : "+defList); //prints [Stack, Queue, Heap, Graph, Hashing, Array, Matrix] Collections.reverse(defList); //Reverses the order of the elements in the specified list. System.out.println("Reverse list : "+defList); //prints [Matrix, Array, Hashing, Graph, Heap, Queue, Stack] Collections.sort(defList); //Sorts the specified list into ascending order. System.out.println("Sorted list : "+defList); //prints [Array, Graph, Hashing, Heap, Matrix, Queue, Stack] System.out.println("Search Heap : " +Collections.binarySearch(defList, "Heap")); Collections.rotate(defList, 1); //Rotates the elements in the specified list by the specified distance. System.out.println("Rotated list : "+defList); //prints [Stack, Array, Graph, Hashing, Heap, Matrix, Queue] defList.add("Heap"); System.out.println("HeapFrequency: " +Collections.frequency(defList, "Heap")); Collections.sort(defList, Collections.reverseOrder()); //Returns a comparator that imposes the reverse of the natural ordering. System.out.println("Reverse order: "+defList); //prints [Stack, Queue, Matrix, Heap, Hashing, Graph, Array] Collections.shuffle(defList); //Randomly permutes the specified list using a default source of randomness. System.out.println("Shuffled list: "+defList); ArrayList newList= new ArrayList(); newList.add("C"); newList.add("C++"); newList.add("Java"); System.out.println("Is defList disjoint to newList? " +Collections.disjoint(defList, newList)); //Returns true if the two specified collections have no elements in common. } public static void dequeDemo() { Deque deQ= new LinkedList(); for (int i= 0; i<5; i++) deQ.add(i+1); System.out.println("Deque : "+deQ); deQ.addFirst("Head"); //Inserts the specified element at the front of this deque System.out.println("AddFirst : "+deQ); deQ.addLast("Tail"); //Inserts the specified element at the end of this deque System.out.println("AddLast : "+deQ); deQ.offer("New Tail"); //Adds an element to the tail System.out.println("Offer : "+deQ); deQ.offerFirst("New Head"); //Adds an element to the head System.out.println("OfferFirst: "+deQ); deQ.offerLast("New Long Tail"); //Adds an element to the tail System.out.println("OfferLast : "+deQ); deQ.push("New Big Head"); //Adds an element to the head. System.out.println("Push : "+deQ); deQ.pop(); //Removes an element from the head System.out.println("Pop : "+deQ); System.out.println("RemoveFirst: "+deQ.removeFirst() +", \t Result-> "+deQ); //Removes the element at the head. System.out.println("RemoveLast : "+deQ.removeLast() +", Result-> "+deQ); //Removes the element at the tail. System.out.print("Iterating : "); Iterator fwdItr= deQ.iterator(); //Returns an iterator over the elements in this deque in proper sequence. while (fwdItr.hasNext()) { System.out.print(fwdItr.next()+", "); } System.out.println(); System.out.print("Reversing : "); Iterator rvsItr= deQ.descendingIterator(); //Returns an iterator over the elements in this deque in reverse sequential order. while (rvsItr.hasNext()) { System.out.print(rvsItr.next()+", "); } System.out.println(); } public static void priorityQueueDemo() { PriorityQueue pQueue= new PriorityQueue(); pQueue.add("C"); pQueue.add("C++"); pQueue.add("Java"); pQueue.add("Python"); Iterator itr= pQueue.iterator(); while (itr.hasNext()) { System.out.print(itr.next()+", "); } System.out.println("Most priority : "+pQueue.peek()); System.out.println("Removing : "+pQueue.remove() //Retrieves and removes the head of this queue +", Second Priority-> "+pQueue.peek()); System.out.println("Removing : "+pQueue.poll() //Retrieves and removes the head of this queue +", Third Priority-> "+pQueue.peek()); System.out.println("Contais Python? "+pQueue.contains("Python")); } public static void queueDemo() { Queue qSet= new LinkedList(); qSet.add("Head"); for (int i= 0; i<5; i++) qSet.add(i+1); qSet.add("Tail"); System.out.println("Queue : "+qSet); System.out.println("Peeking : "+qSet.peek()); //Retrieves, but does not remove, the head of this queue. System.out.println("Element : "+qSet.element()); //Retrieves, but does not remove, the head of this queue. System.out.println("Removing : "+qSet.remove()+", Result-> "+qSet); //Removes and returns the head of the queue. System.out.println("Contais Tail? "+qSet.contains("Tail")); } public static void navigableMapDemo() { NavigableMap nMap= new TreeMap(); nMap.put("C", 888); nMap.put("Y", 999); nMap.put("Z", 909); nMap.put("A", 444); nMap.put("T", 555); nMap.put("B", 666); nMap.put("A", 555); System.out.println("LowerKey : "+nMap.lowerKey("T")); //Returns the greatest key strictly less than the given key C System.out.println("HigherKey : "+nMap.higherKey("T")); //Returns the least key strictly greater than the given key Y System.out.println("FloorKey : "+nMap.floorKey("T")); //Returns the greatest key less than or equal to the given key T System.out.println("CeilingKey : "+nMap.ceilingKey("T")); //Returns the least key greater than or equal to the given key T System.out.println("HeadMap : "+nMap.headMap("C")); //Returns a view of the portion of this map whose keys are strictly less than toKey. System.out.println("TailMap : "+nMap.tailMap("C")); //Returns a view of the portion of this map whose keys are greater than or equal to fromKey. System.out.println("SubMap : "+nMap.subMap("C", "Y")); //Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive. System.out.println("Ascending : "+nMap.keySet()); System.out.println("Descending : "+nMap.descendingKeySet()); } public static void sortedMapDemo() { SortedMap sMap= new TreeMap(); sMap.put(5, "E"); sMap.put(2, "B"); sMap.put(8, "H"); sMap.put(3, "C"); sMap.put(1, "A"); sMap.put(6, "F"); sMap.put(4, "D"); sMap.put(7, "G"); System.out.println("FirstKey : "+sMap.firstKey()); System.out.println("LastKey : "+sMap.lastKey()); System.out.println("HeadMap : "+sMap.headMap(4)); //Returns a view of the portion of this map whose keys are strictly less than toKey. System.out.println("TailMap : "+sMap.tailMap(4)); //Returns a view of the portion of this map whose keys are greater than or equal to fromKey. System.out.println("SubMap : "+sMap.subMap(3, 6)); //Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive. } public static void enumMapDemo() { EnumMap dayMap= new EnumMap(Day.class); dayMap.put(Day.MONDAY, "Compiler Design"); dayMap.put(Day.TUESDAY, "Software Engineering"); dayMap.put(Day.WEDNESDAY, "Algorithm Design"); dayMap.put(Day.THURSDAY, "Computer Networks"); dayMap.put(Day.FRIDAY, "Database Systems"); dayMap.put(Day.SATURDAY, "Advanced JAVA"); dayMap.put(Day.SUNDAY, "Mobile Computing"); System.out.println(dayMap); System.out.println("Size of EnumMap: "+dayMap.size()); System.out.println("EnumMap : "+dayMap); System.out.println("KeySet : "+dayMap.keySet()); System.out.println("EntrySet : "+dayMap.entrySet()); System.out.println("Values : "+dayMap.values()); System.out.println("Key: "+Day.MONDAY+" Value: " +dayMap.get(Day.MONDAY)); System.out.println("EnumMap contains MONDAY? " +dayMap.containsKey(Day.MONDAY)); System.out.println("EnumMap contains Advanced JAVA? " +dayMap.containsValue("Advanced JAVA")); } public static void mapEntry() { HashMap hm= new HashMap(){{ put("Zara", 3434.34); put("Mahnaz", 123.22); put("Ayan", 1378.00); put("Daisy", 99.22); put("Qadir", -19.08); }}; Map.Entry entry; Set set= hm.entrySet(); //returns the Set view containing all the keys and values. Iterator i= set.iterator(); while (i.hasNext()) { entry= (Map.Entry)i.next(); System.out.println(entry.getKey()+" -> "+entry.getValue()); } System.out.println(); System.out.println("Zara acc balance -> "+hm.get("Zara")); //Deposit 1000 into Zara's account double balance= (double)hm.get("Zara"); hm.put("Zara", (balance+1000)); System.out.println("Zara new balance -> "+hm.get("Zara")); } public static void hashMapDemo() { HashMap hMap1= new HashMap(); hMap1.put(1, "James"); //Associates the specified value with the specified key in this map. hMap1.put(3, "Benja"); hMap1.put(4, "Brian"); System.out.println("Boys are : "+hMap1); //prints {1=James, 3=Benja} //Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key. System.out.println("GetorDefault: " +hMap1.getOrDefault(2, "Second Born")); System.out.println("GetorDefault: " +hMap1.getOrDefault(3, "Third Born")); HashMap hMap2= new HashMap(); hMap2.put(2, "Cindy"); hMap2.put(5, "Mercy"); System.out.println("Girls are : "+hMap2); //prints {2=Cindy, 4=Mercy} hMap1.putAll(hMap2); //Copies all of the mappings from hMap2 to this hMap1. System.out.println("Altogether: "+hMap1); //prints {1=James, 2=Cindy, 3=Benja, 4=Mercy} System.out.println("Is Map empty? "+hMap1.isEmpty()); //Returns true if this map contains no key-value mappings. System.out.println("Map size= "+hMap1.size()); //Returns the number of key-value mappings in this map. System.out.println("Contains Key 3? "+hMap1.containsKey(3)); //Returns true if this map contains a mapping for the specified key. System.out.println("Contains Benja? "+hMap1.containsValue("Benja")); //Returns true if this map maps one or more keys to the specified value System.out.println("Get key 5: "+hMap1.get(5)); //Returns the value to which the specified key is mapped System.out.println("Keysets "+hMap1.keySet()); //Returns a Set view of the keys contained in this map. System.out.println("ValueSet "+hMap1.values()); //Returns a Collection view of the values contained in this map. System.out.println("Entrysets "+hMap1.entrySet()); //Returns a Set view of the mappings contained in this map. //hMap1.replace(3, "BEN10"); //Replaces the entry for the specified key hMap1.replace(3, "Benjah", "Benjamin"); ////Replaces the entry for the specified key. NOTE: OldValue must match System.out.println("Replaced Benja: "+hMap1.values()); System.out.print("Removing "+hMap1.remove(4)); //System.out.print("Removing "+hMap1.remove(4, "Brian")); System.out.println(": "+hMap1); } public static void enumSetDemo() { EnumSet calenderDays, weekDays, classDays, freeDays, weekEnds; calenderDays= EnumSet.allOf(Day.class); //Creates an enum set containing all of the elements in the specified element type. weekDays= EnumSet.range(Day.MONDAY, Day.FRIDAY); //Creates an enum set initially containing all of the elements in the range defined by the two specified endpoints.(All Inclusive) classDays= EnumSet.of(Day.TUESDAY, Day.WEDNESDAY, Day.THURSDAY); //Creates an enum set containing all of the elements in the specified element type. freeDays= EnumSet.complementOf(classDays); //Creates an enum set containing elements that are not contained in the specified set. weekEnds= EnumSet.complementOf(weekDays); System.out.println("AllDays = "+calenderDays); System.out.println("WeekDays = "+weekDays); System.out.println("ClassDays= "+classDays); System.out.println("FreeDays = "+freeDays); System.out.println("Weekends = "+weekEnds); } public static void navigableSetDemo() { NavigableSet navSet= new TreeSet(); navSet.add(0); navSet.add(1); navSet.add(2); navSet.add(3); navSet.add(4); navSet.add(5); navSet.add(6); NavigableSet revSet= navSet.descendingSet(); //Returns a reverse order view of the elements contained in this set. System.out.println("Normal : "+navSet); //prints [0, 1, 2, 3, 4, 5, 6] System.out.println("Reverse : "+revSet); //prints [6, 5, 4, 3, 2, 1, 0] System.out.println("Lower : "+navSet.lower(3)); //Returns the greatest element in this set strictly less than the given element 2 System.out.println("Floor : "+navSet.floor(3)); //Returns the greatest element in this set less than or equal to the given element 3 System.out.println("Higher : "+navSet.higher(3)); //Returns the least element in this set strictly greater than the given element, 4 System.out.println("Ceiling: "+navSet.ceiling(3)); //Returns the least element in this set greater than or equal to the given element 3 navSet.pollFirst(); //Retrieves and removes the first (lowest) element System.out.println("PollFirst: "+navSet); //prints [1, 2, 3, 4, 5, 6] navSet.pollLast(); //Retrieves and removes the last (highest) element System.out.println("PollLast : "+navSet); //prints [1, 2, 3, 4, 5] } public static void sortedSetDemo() { SortedSet sSet= new TreeSet(); sSet.add("Brian"); sSet.add("Brendah"); sSet.add("Benjamin"); sSet.add("Benson"); System.out.println("Sorted Set: "+sSet); //prints [Benjamin, Benson, Brendah, Brian] System.out.println("First : "+sSet.first()); //Returns the first (lowest) element currently in this set. Benjamin System.out.println("Last : "+sSet.last()); //Returns the last (highest) element currently in this set. Brian } public static void treeSetDemo() { ArrayList aList= new ArrayList(); aList.add("Cindy"); aList.add("Benja"); TreeSet tSet= new TreeSet(aList); //convert an ArrayList Collection object to TreeSet object. tSet.add("James"); tSet.add("Brian"); tSet.add("Cindy"); //ignores this. Its a Duplicate tSet.add("Mercy"); System.out.println(tSet); //prints [Benja, Brian, Cindy, James, Mercy] System.out.println("First element= "+tSet.first()); //Returns the first (lowest) element currently in this set. ->Benja System.out.println("Last element = "+tSet.last()); //Returns the last (highest) element currently in this set. ->Mercy System.out.println("Contains Benja? "+tSet.contains("Benja")); //Returns true if this set contains the specified element. //Returns a view of the portion of this set whose elements are strictly less than toElement. System.out.println("HeadSet = "+tSet.headSet("E")); //prints [Benja, Brian] //Returns a view of the portion of this set whose elements are greater than or equal to fromElement. System.out.println("TailSet = "+tSet.tailSet("E")); //prints [Cindy, James, Mercy] //Returns a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive. System.out.println("SubSet = "+tSet.subSet("C", "Mercy")); //prints [Cindy, James] tSet.clear(); //Removes all of the elements from this set. System.out.println(tSet); //prints [] } public static void linkedHashSetDemo() { LinkedHashSet lSet= new LinkedHashSet(); lSet.add("James"); lSet.add("Cindy"); lSet.add("Benja"); lSet.add("Brian"); lSet.add("Cindy"); //ignores this. Its a Duplicate lSet.add("Mercy"); System.out.println(lSet); //prints [James, Cindy, Benja, Brian, Mercy] System.out.println("Contains Benja? "+lSet.contains("Benja")); //Returns true if this set contains the specified element. lSet.remove("Brian"); //Removes the specified element from this set if it is present. System.out.println(lSet); //prints [James, Cindy, Benja, Mercy] Iterator i= lSet.iterator(); System.out.println("Using Iterator:"); while (i.hasNext()) { System.out.println("\t"+i.next()); } //Performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception. //NOTE: Can use this as iterator System.out.println("Using Lambda:"); lSet.forEach(e-> System.out.println("\t"+e)); lSet.clear(); //Removes the specified element from this set if it is present. System.out.println(lSet); //prints [] } public static void hashSetDemo() { HashSet hSet1= new HashSet(); hSet1.add("James"); hSet1.add("Cindy"); hSet1.add("Benja"); hSet1.add("Brian"); hSet1.add("Cindy"); //ignores this. Its a Duplicate hSet1.add("Mercy"); System.out.println(hSet1); //prints [Brian, Benja, James, Cindy, Mercy] System.out.println("Contains Benja? "+hSet1.contains("Benja")); //Returns true if this set contains the specified element. hSet1.remove("Brian"); //Removes the specified element from this set if it is present. System.out.println(hSet1); //prints [Benja, James, Cindy, Mercy] Iterator i= hSet1.iterator(); System.out.println("Using Iterator:"); while (i.hasNext()) { System.out.println("\t"+i.next()); } //Performs the given action for each element of the Iterable until all elements have been processed or the action throws an exception. //NOTE: Can use this as iterator System.out.println("Using Lambda:"); hSet1.forEach(e-> System.out.println("\t"+e)); System.out.println("Using forEach:"); for (String e: hSet1) System.out.println("\t"+e); hSet1.clear(); //Removes the specified element from this set if it is present. System.out.println(hSet1); //prints [] } public static void setDemo() { Set hSet= new HashSet(); hSet.add("Wasula James"); hSet.add("Wasula Cindy"); hSet.add("Wasula Benja"); hSet.add("Wasula Cindy"); //ignores this. Its a Duplicate hSet.add("Wasula Mercy"); System.out.println(hSet); //prints [Wasula Benja, Wasula Cindy, Wasula James, Wasula Mercy] Set tSet= new TreeSet(hSet); System.out.println(tSet); Set setA= new HashSet(); setA.addAll(Arrays.asList(new Integer[]{1, 3, 2, 4, 8, 9, 0})); Set setB= new HashSet(); setB.addAll(Arrays.asList(new Integer[]{1, 3, 7, 5, 4, 0, 7, 5})); Set union= new HashSet(setA); union.addAll(setB); System.out.println("Union = "+union); //prints [0, 1, 2, 3, 4, 5, 7, 8, 9] Set intersection= new HashSet(setA); intersection.retainAll(setB); System.out.println("Intersection = "+intersection); //prints [0, 1, 3, 4] Set difference= new HashSet(setA); difference.removeAll(setB); System.out.println("Difference = "+difference); //prints [2, 8, 9] } public static void stackDemo() { Stack defStack= new Stack(); System.out.println(defStack); //prints [] System.out.println("Is stack empty? "+defStack.isEmpty()); //Tests if this vector has no components. defStack.push(1); //Pushes an item onto the top of this stack. defStack.push(2); defStack.push("Top"); defStack.push("NewTop"); System.out.println(defStack); //prints [1, 2, Top, NewTop] System.out.println("\"Top\" is at index: "+defStack.search("Top")); //Returns position from the top of the stack where the object is located; System.out.println("Peeking: "+defStack.peek()); //Looks at the object at the top of this stack without removing it from the stack. System.out.println(defStack); //prints [1, 2, Top, NewTop] defStack.pop(); //Removes the object at the top of this stack and returns that object as the value of this function. System.out.println(defStack); //prints [1, 2, Top] } public static void vectorDemo() { Vector vect= new Vector(); vect.add(1); //Appends the specified element to the end of this Vector. vect.add(2); System.out.println(vect); //prints [1, 2] vect.add(0, "Head"); //Inserts the specified string at index 0 in this Vector. System.out.println(vect); //prints [Head, 1, 2] ArrayList a1= new ArrayList(); a1.add(5); a1.add(6); vect.addAll(a1); //Appends all of the elements in the specified Collection to the end of this Vector System.out.println(vect); //prints [Head, 1, 2, 5, 6] ArrayList a2= new ArrayList(); a2.add(3); a2.add(4); vect.addAll(3, a2); //Inserts all of the elements in the specified Collection into this Vector at the specified position. System.out.println(vect); //prints [Head, 1, 2, 3, 4, 5, 6] //vect.clone() returns a clone of this vector. String x= vect.clone().toString(); System.out.println(x); //prints [Head, 1, 2, 3, 4, 5, 6] System.out.println("Element at index 5= "+vect.get(5)); //Returns the element at the specified position in this Vector. System.out.println("Index of \"Head\" = "+vect.indexOf("Head")); //Returns the index of the first occurrence of the specified element in this vector System.out.println("Is vector empty? "+vect.isEmpty()); //Tests if this vector has no components. Returns False in this case System.out.println("Does vector contain \"Head\" ? " +vect.contains("Head")); //Returns true if this vector contains the specified element. System.out.println("First element= "+vect.firstElement()); //Returns the first component (the item at index 0) of this vector. System.out.println("Last element= "+vect.lastElement()); //Returns the last component of the vector. System.out.println(vect.contains("Head")); //Returns true if this vector contains the specified element. System.out.println("Vector current capacity = "+vect.capacity()); //Returns the current capacity of this vector. //Increases the capacity of this vector, if necessary, to ensure that it can hold at least the number of components specified by the minimum capacity argument. vect.ensureCapacity(20); System.out.println("Vector current capacity = "+vect.capacity()); //Returns the current capacity of this vector. vect.trimToSize(); //Trims the capacity of this vector to be the vector's current size. System.out.println("Vector current capacity = "+vect.capacity()); //Returns the current capacity of this vector. vect.remove(1); //Removes the first occurrence of the specified element in this Vector System.out.println(vect); //prints [Head, 2, 3, 4, 5, 6] Vector vect2= new Vector(); vect2.add("Head"); vect2.add(2); vect2.add(3); vect2.add(4); vect2.add(5); vect2.add(6); System.out.println("Vector 1 hashCode= "+vect.hashCode()); //Returns the hash code value for this Vector. System.out.println("Vector 2 hashCode= "+vect2.hashCode()); //Returns the hash code value for this Vector. System.out.println("Is vector1 equal to vector2 ?"+vect.equals(vect2)); //Compares the specified Object with this Vector for equality. vect2.add("Queue"); System.out.println("Is vector1 equal to vector2 ?"+vect.equals(vect2)); //Compares the specified Object with this Vector for equality. System.out.println("Vector 2 is= "+vect2); vect2.retainAll(vect); System.out.println("Vector 2 is now= "+vect2); System.out.println("Vector size = "+vect.size()); //Returns the number of components in this vector. //NOTE: If the new size is greater than the current size, new null items are added to the end of the vector. // If the new size is less than the current size, all components at index newSize and greater are discarded. vect.setSize(5); //Sets the size of this vector. System.out.println("Vector new size = "+vect.size()); //Returns the number of components in this vector. System.out.println(vect); vect.setElementAt(374, 2); //Sets the component at index 2 of this vector to 374 System.out.println(vect); //prints [Head, 2, 374, 4, 5, 6] vect.removeElement(2); System.out.println("Removed element 2: "+vect); //prints [Head, 374, 4, 5] vect.removeElementAt(2); System.out.println("Removed element at index 2: "+vect); //prints [Head, 374, 5] vect.removeAllElements(); //Removes all components from this vector and sets its size to zero. System.out.println(vect); //prints [] vect.clear(); //Removes all of the elements from this Vector. System.out.println(vect); //prints [] Vector vect3= new Vector(); vect3.add(1); vect3.add(2); vect3.add(3); vect3.add(4); vect3.add(5); Integer vectArr[]= new Integer[vect3.size()]; vect3.copyInto(vectArr); System.out.print("Array copy: "); for (int e: vectArr) System.out.print(e+" "); System.out.println(""); } public static void linkedListDemo() { LinkedList list= new LinkedList(); list.add("Cindy"); //Appends the specified string to the end of this list. list.add("Razy"); list.add("Brian"); System.out.println(list); //prints [Cindy, Razy, Brian] System.out.println(list.size()); //Returns the number of elements in this list. System.out.println("Get at index 2= "+list.get(2)); //Returns the element at the specified position in this list. System.out.println("Brian is at index: "+list.indexOf("Brian")); //Returns the index of the first occurrence of the specified element in this list, list.addFirst("James"); //Inserts the specified string at the beginning of this list System.out.println(list); //prints [James, Cindy, Razy, Brian] list.addLast("Mercy"); //Inserts the specified string to the end of this list System.out.println(list); //prints [James, Cindy, Razy, Brian, Mercy] list.add(2, "Benjah"); //Inserts the string at index 2 in this list. System.out.println(list); //prints [James, Cindy, Benjah, Razy, Brian, Mercy] list.remove("Razy"); //Removes the first occurrence of the specified string from this list, if it is present. System.out.println(list); //prints [James, Cindy, Benjah, Brian, Mercy] list.remove(3); //Removes the element at the specified position in this list. System.out.println(list); //prints [James, Cindy, Benjah, Mercy] //list.removeFirst() removes and returns the first element from this list. System.out.println("Removing: "+list.removeFirst()); //prints James System.out.println(list); //prints [Cindy, Benjah, Mercy] //list.removeLast() removes and returns the last element from this list. System.out.println("Removing: "+list.removeLast()); //prints Mercy System.out.println(list); //prints [Cindy, Benjah] //list.removeLast() retrieves and removes the head (first element) of this list. System.out.println("Removing: "+list.remove()); //prints Cindy System.out.println(list); //prints [Benjah] System.out.println(list.contains("Benjah")); //Returns true if this list contains the specified element. list.clear(); //Removes all of the elements from this list. System.out.println(list); } public static void arrayListDemo() { ArrayList al= new ArrayList(5); //Declaring an ArrayList with initial size of 5 for (int i= 1; i<=5; i++) al.add(i); System.out.println(al); //Printing the ArrayList elements al.remove(3); //Removes ArrayList element at index 3 System.out.println(al); //Prints [1, 2, 3, 5] //al.size() Returns the number of elements in this list. for (int i= 0; i al= new ArrayList(); for (int i= 0; i<10; i++) al.add(i); System.out.println(al); System.out.println("Using Iterator"); for (Iterator itr= al.iterator(); itr.hasNext();) System.out.print(itr.next()+" "); System.out.println(""); System.out.println("Using ForEach Loop"); for (int i: al) System.out.print(i+" "); System.out.println(""); System.out.println("Using Lambda Expressions"); al.forEach(e-> System.out.print(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. public static void listIteratorDemo() { ArrayList al= new ArrayList(); for (int i= 0; i<10; i++) al.add(i); System.out.println(al); ListIterator ltr= al.listIterator(); System.out.println("Print in Forward direction"); while (ltr.hasNext()) //Returns true if this list iterator has more elements when traversing the list in the forward direction. System.out.print(ltr.next()+" "); System.out.println(""); System.out.println("Print in Reverse direction"); while (ltr.hasPrevious()) //Returns true if this list iterator has more elements when traversing the list in the reverse direction. System.out.print(ltr.previous()+" "); System.out.println(""); while (ltr.hasNext()) { int i= (Integer)ltr.next(); System.out.print(i+" "); if ((i%2)==0) { i++; ltr.set(i); //Replaces the last element returned by ListIterator.next //ltr.add(i); //Inserts the specified element into the list (optional operation). } } System.out.println("\n"+al); } public static void iterationsDemo() { ArrayList al= new ArrayList(); for (int i= 0; i<10; i++) al.add(i); System.out.println(al); Iterator itr= al.iterator(); //Returns an iterator over the elements in this list in proper sequence. while (itr.hasNext()) { //Returns true if the iteration has more elements. int i= (Integer)itr.next(); //Returns the next element in the iteration. System.out.print(i+" "); if ((i%2)!=0) itr.remove(); //Removes from the underlying collection the last element returned by this iterator } System.out.println("\n"+al); } public static void enumarationsDemo() { Vector newVect= new Vector(); for (int i= 0; i<10; i++) newVect.addElement(i*10); //Creates a vector and print its contents System.out.println(newVect); //Prints out the vector contents Enumeration e= newVect.elements(); //Returns an enumeration of the components of the newVect. while (e.hasMoreElements()) { //Tests if this enumeration contains more elements. int i= (Integer)e.nextElement(); //Returns the next element of this enumeration. System.out.println(i+" "); } } //prior to JDK 1.2 NOTE: Obsolete public static void hashTableCollection() { Hashtable newTable= new Hashtable(); newTable.put(1, "Jimmy"); //Maps the specified key to the specified value in this hashtable. newTable.put(2, "Cindy"); newTable.put(3, "Benja"); newTable.put(4, "Brian"); newTable.put(5, "Mercy"); System.out.println(newTable.get(2)); //Returns the value to which the specified key 2 is mapped System.out.println(newTable.get(4)); //Returns the value to which the specified key 4 is mapped } //prior to JDK 1.2 NOTE: Obsolete public static void vectorCollection() { Vector newVect= new Vector(); newVect.addElement(10); //Adds the specified component to the end of this vector, increasing its size by one. newVect.addElement(20); //Adds the specified component to the end of this vector, increasing its size by one. System.out.println(newVect.elementAt(0)); //Returns the component at first index. System.out.println(newVect.elementAt(1)); //Returns the component at second index. } //prior to JDK 1.2 public static void arrayCollection() { int newArr[]= new int[]{1,2,3,4}; System.out.println(newArr[0]); //Accessing first element of array System.out.println(newArr[1]); //Accessing second element of array } }

Collections Framework