first commit

TestJavaCollection4.java

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+// Write a java code to demo stack
+import java.util.*;
+public class TestJavaCollection4{
+public static void main(String args[]){
+Stack<String> stack = new Stack<String>();
+stack.push("Ayush");
+stack.push("Garvit");
+stack.push("Amit");
+stack.push("Ashish");
+stack.push("Garvit");
+Iterator<String> itr=stack.iterator();
+while(itr.hasNext()){
+System.out.println(itr.next());
+}
+String topElement = stack.peek();
+System.out.println("The top element of the stack is: "+ topElement);
+stack.pop()
+System.out.println("After POP");
+for(String element : stack){
+    System.out.println(element);
+}
+}
+}

TestJavaCollection7.java

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+//Hashset
+import java.util.*;
+public class TestJavaCollection7{
+public static void main(String args[]){
+    HashSet<String> set=new HashSet<String>();
+    set.add("Ravi");
+    set.add("Vijay");
+    set.add("Ravi");
+    set.add("Ajay");
+    set.add(null);
+
+    Iterator<String>itr=set.iterator();
+    while(itr.hasNext()){
+    System.out.println(itr.next());
+    }
+
+}
+
+}

TestJavaCollection8.java

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+//WAJ to demo linkedhash set
+import java.util.*;
+public class TestJavaCollection8{
+    public static void main(String args[]){
+    LinkedHashSet<String> set=new LinkedHashSet<String>();
+    set.add("Ravi");
+    set.add("Vijay");
+    set.add("ravi");
+    set.add("Ajay");
+
+    Iterator<String> itr=set.iterator();
+    while(itr.hasNext()){
+    System.out.println(itr.next());
+    }
+    }
+}

TestJavaCollection8b.java

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+/WAJ to demo linkedhash set
+import java.util.*;
+public class TestJavaCollection8{
+    public static void main(String args[]){
+    LinkedHashSet<String> set=new LinkedHashSet<String>();
+    set.add("Ravi");
+    set.add("Vijay");
+    set.add("");
+    set.add("Ravi");
+    set.add("Ajay");
+
+    Iterator<String> itr=set.iterator();
+    while(itr.hasNext()){
+    System.out.println(itr.next());
+    }
+    }
+}

TestJavaCollection8c.java

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+//WAJ to demo linkedhash set
+import java.util.*;
+public class TestJavaCollection8c{
+    public static void main(String args[]){
+    LinkedHashSet<String> set=new LinkedHashSet<String>();
+    set.add("Ravi");
+    set.add("Vijay");
+    set.add(null);
+    set.add("Ravi");
+    set.add("Ajay");
+
+    Iterator<String> itr=set.iterator();
+    while(itr.hasNext()){
+    System.out.println(itr.next());
+    }
+    }
+}

TestJavaCollection9.java

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+
+//WAJ to demo Treeset
+import java.util.*;
+public class TestJavaCollection9{
+    public static void main(String args[]){
+    TreeSet<String> set=new TreeSet<String>();
+    set.add("Ravi");
+    set.add("Vijay");
+    set.add("Ajay");
+    set.add("Ravi");
+    set.add("Ajay");
+
+    Iterator<String> itr=set.iterator();
+    while(itr.hasNext()){
+    System.out.println(itr.next());
+    }
+    }
+}

TestJavaCollection9b.java

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+//WAJ to demo Treeset
+import java.util.*;
+public class TestJavaCollection9b{
+    public static void main(String args[]){
+    TreeSet<String> set=new TreeSet<String>();
+    set.add("Ravi");
+    set.add("Vijay");
+    set.add("");
+    set.add(null);
+    set.add("Ravi");
+    set.add("Ajay");
+
+    Iterator<String> itr=set.iterator();
+    while(itr.hasNext()){
+    System.out.println(itr.next());
+    }
+    }
+}