Java Collection framework

Collection Framework/LearnArrayDequeue.java

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+import java.util.*;
+public class LearnArrayDequeue {
+    public static void main(String args[])
+    {
+        ArrayDeque<Integer> adq = new ArrayDeque<>();
+
+        adq.offer(10);
+        adq.offerLast(20);
+        adq.offerFirst(5);
+        adq.offerLast(50);
+        System.out.println(adq);
+
+        System.out.println(adq.peek());
+        System.out.println(adq.peekFirst());
+        System.out.println(adq.peekLast());
+
+        System.out.println(adq.poll());
+        System.out.println(adq);
+        System.out.println(adq.pollFirst());
+        System.out.println(adq.pollLast());
+
+    }
+}

Collection Framework/LearnArrayListObject.java

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+import java.util.*;
+public class LearnArrayListObject
+{
+    public static void main(String[] args) {
+        Student s1 = new Student(111,"Pranav",20);
+        Student s2 = new Student(112,"Tejas",21);
+        Student s3 = new Student(113,"Psrp",20);
+        List<Student> st = new ArrayList<Student>();
+
+        st.add(s1);
+        st.add(s2);
+        st.add(s3);
+
+        //System.out.println(st);------>it prints addresses
+
+//        Iterator itr=st.iterator();
+//        while(itr.hasNext()){
+//            Student s=(Student)itr.next();
+//            System.out.println(s.rollno+" "+s.name+" "+s.age);
+//        }
+
+        //easy method---->
+        for (Student s : st) {
+            System.out.println(s.rollno + " " + s.name + " " + s.age);
+        }
+
+        System.out.println(st);//after using toString in student class it shows correct output
+    }
+}

Collection Framework/LearnArraylistOperations.java

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+import java.util.*;
+public class LearnArraylistOperations
+{
+    public static void main(String args[]){
+        List<Integer> list = new ArrayList<>();
+        list.add(10);
+        list.add(20);
+        list.add(30);
+        list.add(40);
+        System.out.println(list);
+
+        list.add(1,15);
+        System.out.println(list);
+
+        List<Integer> newlist = new ArrayList<>();
+        newlist.add(50);
+        newlist.add(60);
+
+        list.addAll(newlist);
+        System.out.println(list);
+
+        newlist.clear();
+        System.out.println(newlist);
+
+        System.out.println(list.get(1));
+     //   System.out.println(newlist.get(1));
+
+        list.remove(1);
+        list.remove(Integer.valueOf(60));
+
+        list.set(2,25);
+        System.out.println(list);
+
+        System.out.println(list.contains(25));
+        System.out.println(list.contains(30));
+        list.add(85);
+        list.add(60);
+        list.add(77);
+        list.add(52);
+
+        for(int i = 0;i < list.size();i++){
+            System.out.println("Element is "+ list.get(i));
+        }
+
+        System.out.println();
+
+        for(Integer element:list){
+            System.out.println("for each element "+ element);
+        }
+
+        System.out.println();
+
+        Iterator<Integer> it = list.iterator();
+        while(it.hasNext()){
+            System.out.println("Iterator element "+ it.next());
+        }
+
+        Collections.sort(list);
+
+        System.out.println(list);
+    }
+}

Collection Framework/LearnArraysClass.java

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+import java.util.*;
+public class LearnArraysClass {
+    public static void main(String[] args) {
+        int[] numbers = {1,3,5,7,9,11,13,15};
+
+        int index = Arrays.binarySearch(numbers,5);
+        System.out.println(index);
+        int index1 = Arrays.binarySearch(numbers,6);
+        System.out.println(index1);
+
+        int[] numbers1 = {1,31,55,17,91,14,48,73};
+        Arrays.sort(numbers1);
+        //System.out.println(numbers1);--------->shows address, no correct o/p
+        System.out.println(Arrays.toString(numbers1));
+        for(Integer num:numbers1)
+        {
+            System.out.println(num);
+        }
+//        Arrays.fill(numbers,25);
+//        System.out.println(Arrays.toString(numbers));
+
+
+
+    }
+}

Collection Framework/LearnCollectionClass.java

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+import java.util.*;
+public class LearnCollectionClass
+{
+    public static void main(String[] args) {
+        List<Integer>list = new ArrayList<>();
+        list.add(25);
+        list.add(7);
+        list.add(13);
+        list.add(42);
+        list.add(34);
+        list.add(71);
+
+        System.out.println(list);
+        Collections.sort(list);
+        System.out.println(list);
+
+        System.out.println(Collections.min(list));
+        System.out.println(Collections.max(list));
+
+        Collections.sort(list,Comparator.reverseOrder());
+        System.out.println(list);
+
+        System.out.println(Collections.frequency(list,25));
+
+        Student s1 = new Student(111,"Pranav",20);
+        Student s3 = new Student(113,"Psrp",20);
+        Student s2 = new Student(112,"Tejas",21);
+        Student s4 = new Student(102,"PP",21);
+
+        List<Student> st = new ArrayList<Student>();
+
+        st.add(s4);
+        st.add(s2);
+        st.add(s3);
+        st.add(s1);
+
+        System.out.println(st);
+        Collections.sort(st);
+        System.out.println(st);
+        Collections.sort(st,((o1, o2) -> o1.name.compareTo(o2.name)));
+        System.out.println(st);
+    }
+}

Collection Framework/LearnHashMap.java

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+import javax.swing.text.html.parser.Entity;
+import java.util.*;
+public class LearnHashMap
+{
+    public static void main(String[] args) {
+        Map<String,Integer> numbers = new HashMap<>();
+        numbers.put("one",1);
+        numbers.put("five",5);
+        numbers.put("two",2);
+        numbers.put("three",3);
+
+        //numbers.put("two",22); ------> override the old value
+        //numbers.putIfAbsent("two",22);
+
+        System.out.println(numbers);
+        for(Map.Entry<String,Integer> e: numbers.entrySet()){
+            System.out.println(e);
+        }
+//        for(Map.Entry<String,Integer> e: numbers.entrySet()){
+//            System.out.println(e.getKey());
+//            System.out.println(e.getValue());
+//        }
+        for(String key: numbers.keySet()){
+            System.out.println(key);
+        }
+        System.out.println(numbers.containsKey("one"));
+
+        numbers.replace("one",1,11);
+        System.out.println(numbers);
+    }
+}

Collection Framework/LearnHashset.java

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+import java.util.*;
+public class LearnHashset {
+    public static void main(String args[]){
+        Set<Integer> set = new HashSet<>();
+
+        set.add(10);
+        set.add(7);
+        set.add(25);
+        set.add(52);
+        set.add(44);
+
+        System.out.println(set);
+        set.remove(52);
+        System.out.println(set);
+
+        System.out.println(set.contains(25));
+        System.out.println(set.isEmpty());
+
+        set.add(10);
+        System.out.println(set);
+
+        set.remove(22);
+        System.out.println(set);
+
+        Set<Integer> set1 = new HashSet<>();
+        set1.add(101);
+        set1.add(150);
+        set1.add(122);
+
+        set.addAll(set1);
+        System.out.println(set);
+
+        set.removeAll(set1);
+        System.out.println(set);
+    }
+}
+
+
+

Collection Framework/LearnHashsetObject.java

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+import java.util.*;
+
+public class LearnHashsetObject
+{
+    public static void main(String[] args) {
+        Set<Student>st = new HashSet<Student>();
+        Student s1 = new Student(111,"Pranav",20);
+        Student s2 = new Student(112,"Tejas",21);
+        Student s3 = new Student(113,"Psrp",20);
+        Student s4 = new Student(113,"PR",21);
+
+        st.add(s1);
+        st.add(s2);
+        st.add(s3);
+        st.add(s4);
+
+        //System.out.println(st);
+
+        for(Student s:st)
+        {
+            System.out.println(s.name + " " + s.rollno + " " + s.age);
+        }
+    }
+}

Collection Framework/LearnLinkedHashset.java

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+import java.util.*;
+public class LearnLinkedHashset {
+    public static void main(String args[]){
+        Set<Integer> set = new LinkedHashSet<>();
+
+        set.add(10);
+        set.add(7);
+        set.add(25);
+        set.add(52);
+        set.add(44);
+
+        System.out.println(set);
+        set.remove(52);
+        System.out.println(set);
+
+        System.out.println(set.contains(25));
+        System.out.println(set.isEmpty());
+
+        set.add(10);
+        System.out.println(set);
+    }
+}
+
+
+

Collection Framework/LearnLinkedListQueue.java

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+import java.util.*;
+public class LearnLinkedListQueue {
+    public static void main(String args[]){
+        Queue<Integer> que = new LinkedList<>();
+
+        que.add(10);
+        que.add(20);
+        que.add(30); //add throws exception when error
+        System.out.println(que);
+
+        que.offer(40);
+        que.offer(50);// use offer while adding element
+        System.out.println(que);
+
+        System.out.println(que.remove()); //throws exception
+        System.out.println(que.poll());
+        System.out.println(que.element()); //throws exception
+        System.out.println(que.peek());
+        System.out.println(que.isEmpty());
+    }
+}

Collection Framework/LearnPriorityQueue.java

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+import java.util.*;
+public class LearnPriorityQueue {
+    public static void main(String args[]){
+        Queue<Integer> pq = new PriorityQueue<>();
+        pq.offer(40);
+        pq.offer(20);
+        pq.offer(50);
+        pq.offer(30);
+        pq.offer(10);
+
+        System.out.println(pq);
+        System.out.println(pq.peek());
+        pq.poll();
+        System.out.println(pq);
+
+        Queue<String> pqs = new PriorityQueue<>();
+        pqs.offer("Tejas");
+        pqs.offer("Ketan");
+        pqs.offer("Prathmesh");
+        pqs.offer("Abhi");
+        pqs.offer("Aabhi");
+
+        System.out.println(pqs);
+
+        Queue<Integer> pqr = new PriorityQueue<>(Comparator.reverseOrder());
+        pqr.offer(40);
+        pqr.offer(20);
+        pqr.offer(50);
+        pqr.offer(30);
+        pqr.offer(10);
+
+        System.out.println(pqr);
+        System.out.println(pqr.peek());
+        pqr.poll();
+        System.out.println(pqr);
+
+    }
+}

Collection Framework/LearnStackCollection.java

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+import java.util.*;
+public class LearnStackCollection {
+    public static void main(String args[])
+    {
+        Stack<String> students = new Stack<>();
+        students.push("Tejas");
+        students.push("Sharvari");
+        students.push("Jayashri");
+
+        System.out.println(students);
+
+        students.pop();
+        System.out.println(students);
+
+        System.out.println(students.isEmpty());
+        System.out.println(students.peek());
+
+        System.out.println(students.empty());
+
+        Iterator<String> it = students.iterator();
+        while(it.hasNext()){
+            System.out.println("stack elements : "+it.next());
+        }
+    }
+}