diff --git a/Single-and-Multiple-Inheritence/BMIMachine.java b/Single-and-Multiple-Inheritence/BMIMachine.java
new file mode 100644
index 0000000..e359bc4
--- /dev/null
+++ b/Single-and-Multiple-Inheritence/BMIMachine.java
@@ -0,0 +1,17 @@
+package com.vivek.javacodes7;
+
+public class BMIMachine extends HeartMonitor
+{
+    public static void main(String[] args)
+    {
+        System.out.println(getMaxHeartRate(30));
+    }
+
+    public static int getMaxHeartRate(int age) 
+    {
+        int result;
+        result = 230-age;
+        System.out.println("___Method executed from Sub-class___");
+        return result;
+    }
+}
diff --git a/Single-and-Multiple-Inheritence/HeartMonitor.java b/Single-and-Multiple-Inheritence/HeartMonitor.java
new file mode 100644
index 0000000..d528c23
--- /dev/null
+++ b/Single-and-Multiple-Inheritence/HeartMonitor.java
@@ -0,0 +1,17 @@
+package com.vivek.javacodes7;
+
+public class HeartMonitor 
+{
+    public static void main(String[] args)
+    {
+        System.out.println(getMaxHeartRate(30));
+    }
+
+    public static int getMaxHeartRate(int age) 
+    {
+        int result;
+        result = 220-age;
+        System.out.println("___Method executed from Base-class___");
+        return result;
+    }
+}
diff --git a/Vivek Parmar/Abstraction/Abstraction_1.java b/Vivek Parmar/Abstraction/Abstraction_1.java
new file mode 100644
index 0000000..848d798
--- /dev/null
+++ b/Vivek Parmar/Abstraction/Abstraction_1.java	
@@ -0,0 +1,18 @@
+package com.vivek.javacodes;
+
+public class Abstraction_1 extends Abstraction_2{
+	
+	public void anotherMethod()
+	{
+		System.out.println("Abstract method.");
+	}
+
+	public static void main(String[] args) {
+		
+		Abstraction_2 obj = new Abstraction_1();
+		obj.anotherMethod();
+		System.out.println(" ");
+		obj.myMethod();
+	}
+
+}
diff --git a/Vivek Parmar/Abstraction/Abstraction_2.java b/Vivek Parmar/Abstraction/Abstraction_2.java
new file mode 100644
index 0000000..72ef618
--- /dev/null
+++ b/Vivek Parmar/Abstraction/Abstraction_2.java	
@@ -0,0 +1,11 @@
+package com.vivek.javacodes;
+
+abstract class Abstraction_2 {
+
+	public void myMethod() {
+		System.out.println("Abstraction-2.");
+	}
+	
+	abstract public void anotherMethod();
+
+}
diff --git a/Vivek Parmar/ArrayDemo.java b/Vivek Parmar/ArrayDemo.java
new file mode 100644
index 0000000..5732ae8
--- /dev/null
+++ b/Vivek Parmar/ArrayDemo.java	
@@ -0,0 +1,36 @@
+package com.vivek.javacodes;
+
+public class ArrayDemo {
+
+	public static void main(String[] args) {
+		
+		System.out.println("First method: ");
+		int[] numsArray = new int[10];
+		numsArray[0] = 0;
+		numsArray[1] = 1;
+		numsArray[2] = 2;
+		numsArray[3] = 3;
+		numsArray[4] = 4;
+		numsArray[5] = 5;
+		numsArray[6] = 6;
+		numsArray[7] = 7;
+		numsArray[8] = 8;
+		numsArray[9] = 9;
+		
+		for(int i = 0; i<numsArray.length; i++) {
+			System.out.println(numsArray[i]);
+		}
+		
+		System.out.println();
+		
+		System.out.println("Second method: ");
+		char[] charArrays =  {'a','b','c','d','e','f'};
+		System.out.println(charArrays[0]);
+		System.out.println(charArrays[1]);
+		System.out.println(charArrays[2]);
+		System.out.println(charArrays[3]);
+		System.out.println(charArrays[4]);
+		System.out.println(charArrays[5]);
+	}
+
+}
diff --git a/Vivek Parmar/ChainedExceptions.java b/Vivek Parmar/ChainedExceptions.java
new file mode 100644
index 0000000..c785f65
--- /dev/null
+++ b/Vivek Parmar/ChainedExceptions.java	
@@ -0,0 +1,28 @@
+package com.vivek.javacodes6;
+
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class ChainedExceptions 
+{
+	public static void main(String[] args) 
+	{
+		try
+		{
+			Scanner scanner = new Scanner(System.in);
+			
+			System.out.print("Please enter your height in cms: ");
+			float height = scanner.nextFloat();
+			
+			double idealWeight = 50 + (0.91 * (height - 152.4));
+			System.out.println("Your ideal weight should be " + idealWeight + "KG.");
+			
+			scanner.close();
+		}
+		catch(InputMismatchException e)
+		{
+			throw new NumberFormatException();
+		}
+	}
+
+}
diff --git a/Vivek Parmar/Demo1.java b/Vivek Parmar/Demo1.java
new file mode 100644
index 0000000..254bc45
--- /dev/null
+++ b/Vivek Parmar/Demo1.java	
@@ -0,0 +1,18 @@
+package com.vivek.javacodes3;
+
+public class Demo1 
+{
+	void emp_info(String name, int age)
+	{
+		System.out.println("Type-1:");
+		System.out.println("Name: " + name);
+		System.out.println("Age: " + age);
+	}
+	
+	void emp_info(int age, String name)
+	{
+		System.out.println("Type-2:");
+		System.out.println("Name: " + name);
+		System.out.println("Age: " + age);
+	}
+}
diff --git a/Vivek Parmar/Demo2.java b/Vivek Parmar/Demo2.java
new file mode 100644
index 0000000..0fdab18
--- /dev/null
+++ b/Vivek Parmar/Demo2.java	
@@ -0,0 +1,14 @@
+package com.vivek.javacodes3;
+
+public class Demo2 extends Demo1
+{
+
+	public static void main(String[] args) 
+	{
+		Demo2 obj = new Demo2();
+		obj.emp_info("Vivek", 22);
+		System.out.println();
+		obj.emp_info(22, "Vivek");
+	}
+
+}
diff --git a/Vivek Parmar/Employee.java b/Vivek Parmar/Employee.java
new file mode 100644
index 0000000..ad9030e
--- /dev/null
+++ b/Vivek Parmar/Employee.java	
@@ -0,0 +1,32 @@
+package com.vivek.javacodes3;
+
+public class Employee 
+{
+	public static void main(String[] args) 
+	{
+		Employee1 emp1 = new Employee1();
+		emp1.name = "Soham";
+		emp1.age = 22;
+		emp1.salary = 45000.00;
+		
+		Employee2 emp2 = new Employee2();
+		emp2.name = "Parsh";
+		emp2.age = 23;
+		emp2.salary = 50000.00;
+		emp2.language = "Java";
+		
+		Employee3 emp3 = new Employee3();
+		emp3.name = "Jain";
+		emp3.age = 21;
+		emp3.salary = 55000.00;
+		emp3.language = "C++";
+		emp3.databaseTool = "MySQL";
+		
+		emp1.printData();
+		System.out.println();
+		emp2.printData();
+		System.out.println();
+		emp3.printData();
+	}
+
+}
diff --git a/Vivek Parmar/Employee1.java b/Vivek Parmar/Employee1.java
new file mode 100644
index 0000000..5ec1877
--- /dev/null
+++ b/Vivek Parmar/Employee1.java	
@@ -0,0 +1,15 @@
+package com.vivek.javacodes3;
+
+public class Employee1
+{
+	String name;
+	int age;
+	double salary;
+	
+	public void printData()
+	{
+		System.out.println("Name: " + name);
+		System.out.println("Age: " + age);
+		System.out.println("Salary: " + salary);
+	}
+}
diff --git a/Vivek Parmar/Employee2.java b/Vivek Parmar/Employee2.java
new file mode 100644
index 0000000..283f4f5
--- /dev/null
+++ b/Vivek Parmar/Employee2.java	
@@ -0,0 +1,12 @@
+package com.vivek.javacodes3;
+
+public class Employee2 extends Employee1 
+{
+	String language;
+	
+	public void printData()
+	{
+		super.printData();
+		System.out.println("Language: " + language);
+	}
+}
diff --git a/Vivek Parmar/Employee3.java b/Vivek Parmar/Employee3.java
new file mode 100644
index 0000000..e8e1543
--- /dev/null
+++ b/Vivek Parmar/Employee3.java	
@@ -0,0 +1,12 @@
+package com.vivek.javacodes3;
+
+public class Employee3 extends Employee2
+{
+	String databaseTool;
+	
+	public void printData()
+	{
+		super.printData();
+		System.out.println("Database Tool: " + databaseTool);
+	}
+}
diff --git a/Vivek Parmar/Encapsulation-&-Access Specifier/Ex1.java b/Vivek Parmar/Encapsulation-&-Access Specifier/Ex1.java
new file mode 100644
index 0000000..bf8b740
--- /dev/null
+++ b/Vivek Parmar/Encapsulation-&-Access Specifier/Ex1.java	
@@ -0,0 +1,9 @@
+package com.vivek.javacodes5;
+
+public class Ex1 
+{
+	private int a = 100;
+	public int b = 90;
+	protected int c = 80;
+	int d = 19; //no modifier
+}
diff --git a/Vivek Parmar/Encapsulation-&-Access Specifier/Ex2.java b/Vivek Parmar/Encapsulation-&-Access Specifier/Ex2.java
new file mode 100644
index 0000000..5e0a57b
--- /dev/null
+++ b/Vivek Parmar/Encapsulation-&-Access Specifier/Ex2.java	
@@ -0,0 +1,14 @@
+package com.vivek.javacodes5;
+
+public class Ex2 extends Ex1
+{
+	public static void main(String[] args)
+	{
+		Ex2 obj = new Ex2();
+//		System.out.println(obj.a); //it will throw an error, because 'a' is private
+		System.out.println("B: " + obj.b);
+		System.out.println("C: " + obj.c);
+		System.out.println("D: " + obj.d);
+	}
+
+}
diff --git a/Vivek Parmar/Ex1.java b/Vivek Parmar/Ex1.java
new file mode 100644
index 0000000..5095b81
--- /dev/null
+++ b/Vivek Parmar/Ex1.java	
@@ -0,0 +1,11 @@
+package com.vivek.javacodes3;
+
+public class Ex1 {
+
+	public int x = 5;
+	public void set_x(int a) 
+	{
+		x=a;
+	}
+
+}
diff --git a/Vivek Parmar/Ex2.java b/Vivek Parmar/Ex2.java
new file mode 100644
index 0000000..a65104e
--- /dev/null
+++ b/Vivek Parmar/Ex2.java	
@@ -0,0 +1,10 @@
+package com.vivek.javacodes3;
+
+public class Ex2 extends Ex1 
+{
+	public int getEx2()
+	{
+		set_x(7);
+		return x;
+	}
+}
diff --git a/Vivek Parmar/Ex3.java b/Vivek Parmar/Ex3.java
new file mode 100644
index 0000000..8f767a9
--- /dev/null
+++ b/Vivek Parmar/Ex3.java	
@@ -0,0 +1,13 @@
+package com.vivek.javacodes3;
+
+public class Ex3 extends Ex2 
+{
+	public static void main(String[] args)
+	{
+		Ex1 ex1 = new Ex1();
+		Ex2 ex2 = new Ex2();
+		
+		System.out.println(ex1.x);
+		System.out.println(ex2.getEx2());
+	}
+}
diff --git a/Vivek Parmar/Example.txt b/Vivek Parmar/Example.txt
new file mode 100644
index 0000000..34014cd
--- /dev/null
+++ b/Vivek Parmar/Example.txt	
@@ -0,0 +1,17 @@
+#File: Ex1.java
+
+class Example1
+{
+	public static void main(String[] args)
+	{
+		System.out.println("Hello Vivek");
+	}
+}
+
+#To compile it via cmd:
+
+javac Ex1.java
+
+#To run it in cmd:
+
+java Example1
diff --git a/Vivek Parmar/ExceptionHandling.java b/Vivek Parmar/ExceptionHandling.java
new file mode 100644
index 0000000..cd26df1
--- /dev/null
+++ b/Vivek Parmar/ExceptionHandling.java	
@@ -0,0 +1,32 @@
+package com.vivek.javacodes6;
+
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class ExceptionHandling 
+{
+	public static void main(String[] args) 
+	{	
+		//Maximum heart beat of the user
+		
+		try
+		{
+			System.out.println("___:Maximum Heart Rate Calculator:___");
+			Scanner scanner = new Scanner(System.in);
+			
+			System.out.print("Enter your age: ");
+			int age = scanner.nextInt();
+			
+			int max_heart_rate = 220 - age;
+			
+			System.out.println("Your maximum heart rate is " + max_heart_rate + ".");
+			
+			scanner.close();
+		} 
+		catch(InputMismatchException e) 
+		{
+			System.out.println("Please enter age in number format.");
+		}
+	}
+
+}
diff --git a/Vivek Parmar/Interface-&-Abstraction/Bank.java b/Vivek Parmar/Interface-&-Abstraction/Bank.java
new file mode 100644
index 0000000..b8daabd
--- /dev/null
+++ b/Vivek Parmar/Interface-&-Abstraction/Bank.java	
@@ -0,0 +1,6 @@
+package com.vivek.javacodes4;
+
+public interface Bank 
+{
+	float rateOfInterest();
+}
diff --git a/Vivek Parmar/Interface-&-Abstraction/InterestTest.java b/Vivek Parmar/Interface-&-Abstraction/InterestTest.java
new file mode 100644
index 0000000..9dd12e0
--- /dev/null
+++ b/Vivek Parmar/Interface-&-Abstraction/InterestTest.java	
@@ -0,0 +1,14 @@
+package com.vivek.javacodes4;
+
+public class InterestTest 
+{
+	public static void main(String[] args) 
+	{
+		Bank b = new SBI();
+		Bank p = new PNB();
+		
+		System.out.println("SBI ROI: " + b.rateOfInterest());
+		System.out.println("PNB ROI: " + p.rateOfInterest());
+	}
+
+}
diff --git a/Vivek Parmar/Interface-&-Abstraction/PNB.java b/Vivek Parmar/Interface-&-Abstraction/PNB.java
new file mode 100644
index 0000000..40fe3c4
--- /dev/null
+++ b/Vivek Parmar/Interface-&-Abstraction/PNB.java	
@@ -0,0 +1,9 @@
+package com.vivek.javacodes4;
+
+public class PNB implements Bank
+{
+	public float rateOfInterest()
+	{
+		return 9.7f;
+	}
+}
diff --git a/Vivek Parmar/Interface-&-Abstraction/Printable.java b/Vivek Parmar/Interface-&-Abstraction/Printable.java
new file mode 100644
index 0000000..dd2e0a1
--- /dev/null
+++ b/Vivek Parmar/Interface-&-Abstraction/Printable.java	
@@ -0,0 +1,6 @@
+package com.vivek.javacodes4;
+
+public interface Printable 
+{
+	void print();
+}
diff --git a/Vivek Parmar/Interface-&-Abstraction/SBI.java b/Vivek Parmar/Interface-&-Abstraction/SBI.java
new file mode 100644
index 0000000..3c892da
--- /dev/null
+++ b/Vivek Parmar/Interface-&-Abstraction/SBI.java	
@@ -0,0 +1,9 @@
+package com.vivek.javacodes4;
+
+public class SBI implements Bank
+{
+	public float rateOfInterest()
+	{
+		return 9.15f;
+	}
+}
diff --git a/Vivek Parmar/Interface-&-Abstraction/Showable.java b/Vivek Parmar/Interface-&-Abstraction/Showable.java
new file mode 100644
index 0000000..26334ef
--- /dev/null
+++ b/Vivek Parmar/Interface-&-Abstraction/Showable.java	
@@ -0,0 +1,6 @@
+package com.vivek.javacodes4;
+
+public interface Showable 
+{
+	void show();
+}
diff --git a/Vivek Parmar/Interface-&-Abstraction/Test.java b/Vivek Parmar/Interface-&-Abstraction/Test.java
new file mode 100644
index 0000000..485b7a6
--- /dev/null
+++ b/Vivek Parmar/Interface-&-Abstraction/Test.java	
@@ -0,0 +1,23 @@
+package com.vivek.javacodes4;
+
+public class Test implements Printable, Showable
+{
+	@Override
+	public void show() 
+	{
+		System.out.println("This is a show method from 'Showable' method.");
+	}
+
+	@Override
+	public void print() 
+	{
+		System.out.println("This is a print method from 'Printable' method.");
+	}
+
+	public static void main(String[] args) 
+	{
+		Test obj = new Test();
+		obj.show();
+		obj.print();
+	}
+}
diff --git a/Vivek Parmar/JShell.txt b/Vivek Parmar/JShell.txt
new file mode 100644
index 0000000..fde33a3
--- /dev/null
+++ b/Vivek Parmar/JShell.txt	
@@ -0,0 +1,44 @@
+C:\Users\vivek>jshell
+|  Welcome to JShell -- Version 19
+|  For an introduction type: /help intro
+
+jshell> String print(String name){
+   ...>     return name+' '+name;
+   ...> }
+|  created method print(String)
+
+jshell> print("Vivek");
+$2 ==> "Vivek Vivek"
+
+jshell> String print2(String fname, String lname){
+   ...>     return "First Name: " + fname;
+   ...> }
+|  created method print2(String,String)
+
+jshell> print2("Vivek")
+|  Error:
+|  method print2 in class  cannot be applied to given types;
+|    required: java.lang.String,java.lang.String
+|    found:    java.lang.String
+|    reason: actual and formal argument lists differ in length
+|  print2("Vivek")
+|  ^----^
+
+jshell> print2("Vivek","Parmar")
+$4 ==> "First Name: Vivek"
+
+jshell> String print3(String fname, String lname){
+   ...>     return "First Name: " + fname + "/n" + "Last Name: " + lname;
+   ...> }
+|  created method print3(String,String)
+
+jshell> print3("Vivek","Parmar")
+$6 ==> "First Name: Vivek/nLast Name: Parmar"
+
+jshell> int sum(int a, int b){
+   ...>     return a+b;
+   ...> }
+|  created method sum(int,int)
+
+jshell> sum(6,4)
+$8 ==> 10
diff --git a/Vivek Parmar/Java-Lambda-Expression/Lambda_P1.java b/Vivek Parmar/Java-Lambda-Expression/Lambda_P1.java
new file mode 100644
index 0000000..fb4dee5
--- /dev/null
+++ b/Vivek Parmar/Java-Lambda-Expression/Lambda_P1.java	
@@ -0,0 +1,6 @@
+package com.vivek.javacodes5;
+
+public interface Lambda_P1 
+{
+	public String say();
+}
diff --git a/Vivek Parmar/Java-Lambda-Expression/Lambda_P2.java b/Vivek Parmar/Java-Lambda-Expression/Lambda_P2.java
new file mode 100644
index 0000000..63e6f95
--- /dev/null
+++ b/Vivek Parmar/Java-Lambda-Expression/Lambda_P2.java	
@@ -0,0 +1,14 @@
+package com.vivek.javacodes5;
+
+public class Lambda_P2 
+{
+	public static void main(String[] args) 
+	{
+		Lambda_P1 obj = ()->
+		{
+			return "Hello, I am Vivek.";				
+		};
+		System.out.println(obj.say());
+	}
+
+}
diff --git a/Vivek Parmar/Java-Lambda-Expression/Lambda_P3.java b/Vivek Parmar/Java-Lambda-Expression/Lambda_P3.java
new file mode 100644
index 0000000..7ef9c35
--- /dev/null
+++ b/Vivek Parmar/Java-Lambda-Expression/Lambda_P3.java	
@@ -0,0 +1,11 @@
+package com.vivek.javacodes5;
+
+public interface Lambda_P3
+{
+	void abstractMsg(String name);
+	
+	default void normalMsg() 
+	{
+		System.out.print("Hi, ");
+	}
+}
diff --git a/Vivek Parmar/Java-Lambda-Expression/Lambda_P4.java b/Vivek Parmar/Java-Lambda-Expression/Lambda_P4.java
new file mode 100644
index 0000000..5e307ff
--- /dev/null
+++ b/Vivek Parmar/Java-Lambda-Expression/Lambda_P4.java	
@@ -0,0 +1,16 @@
+package com.vivek.javacodes5;
+
+public class Lambda_P4 {
+
+	public static void main(String[] args) 
+	{
+		Lambda_P3 obj = (String name)->
+		{
+			System.out.print(name + " Parmar.");
+		};
+		
+		obj.normalMsg();
+		obj.abstractMsg("Vivek");
+	}
+
+}
diff --git a/Vivek Parmar/Java-Lambda-Expression/Lambda_P5.java b/Vivek Parmar/Java-Lambda-Expression/Lambda_P5.java
new file mode 100644
index 0000000..bfb8a58
--- /dev/null
+++ b/Vivek Parmar/Java-Lambda-Expression/Lambda_P5.java	
@@ -0,0 +1,32 @@
+package com.vivek.javacodes5;
+
+import java.util.ArrayList;
+
+public class Lambda_P5 {
+
+	public static void main(String[] args) 
+	{
+		ArrayList<String> arrayListEx1 = new ArrayList<String>();	
+		arrayListEx1.add("Vivek");
+		arrayListEx1.add("Soham");
+		arrayListEx1.add("Ranak");
+		
+		System.out.println("Names: ");
+		arrayListEx1.forEach(n -> System.out.println(n));
+		
+		System.out.println();
+		
+		ArrayList<Integer> arrayListEx2 = new ArrayList<Integer>();
+		arrayListEx2.add(100);
+		arrayListEx2.add(10005);
+		arrayListEx2.add(100000);
+		
+		System.out.println("Numbers: ");
+		arrayListEx2.forEach(n ->
+		{
+			if(n%2 == 0) System.out.println(n);
+		}
+				);
+	}
+
+}
diff --git a/Vivek Parmar/Lambda_P1.java b/Vivek Parmar/Lambda_P1.java
new file mode 100644
index 0000000..fb4dee5
--- /dev/null
+++ b/Vivek Parmar/Lambda_P1.java	
@@ -0,0 +1,6 @@
+package com.vivek.javacodes5;
+
+public interface Lambda_P1 
+{
+	public String say();
+}
diff --git a/Vivek Parmar/Lists-Interface-and-ArrayList/MyArrayList.java b/Vivek Parmar/Lists-Interface-and-ArrayList/MyArrayList.java
new file mode 100644
index 0000000..775187b
--- /dev/null
+++ b/Vivek Parmar/Lists-Interface-and-ArrayList/MyArrayList.java	
@@ -0,0 +1,86 @@
+package com.vivek.javacodes7;
+
+import java.util.ArrayList;
+
+public class MyArrayList 
+{
+	public static void main(String[] args) 
+	{
+		ArrayList<Integer> arrayList1 = new ArrayList<Integer>();
+		
+		arrayList1.add(1);
+		arrayList1.add(2);
+		arrayList1.add(3);
+		arrayList1.add(4);
+		arrayList1.add(5);
+	
+		System.out.println("Printing arrayList1:");
+		System.out.println(arrayList1.get(0));
+		System.out.println(arrayList1.get(1));
+		System.out.println(arrayList1.get(2));
+		System.out.println(arrayList1.get(3));
+		System.out.println(arrayList1.get(4));
+		System.out.println();
+		
+		System.out.println("Printing updated arrayList1:");
+		arrayList1.add(0, 0);
+		System.out.println(arrayList1.get(0));
+		System.out.println(arrayList1.get(1));
+		System.out.println(arrayList1.get(2));
+		System.out.println(arrayList1.get(3));
+		System.out.println(arrayList1.get(4));
+		System.out.println(arrayList1.get(5));
+		System.out.println();
+		
+		ArrayList<Integer> arrayList2 = new ArrayList<Integer>();
+		arrayList2.addAll(arrayList1);
+		System.out.println("Printing arrayList2:");
+		System.out.println(arrayList2.get(0));
+		System.out.println(arrayList2.get(1));
+		System.out.println(arrayList2.get(2));
+		System.out.println(arrayList2.get(3));
+		System.out.println(arrayList2.get(4));
+		System.out.println(arrayList2.get(5));
+		System.out.println();
+		
+		arrayList2.clear();
+		try 
+		{
+		System.out.println("Printing arrayList2:");
+		System.out.println(arrayList2.get(0));
+		System.out.println(arrayList2.get(1));
+		System.out.println(arrayList2.get(2));
+		System.out.println(arrayList2.get(3));
+		System.out.println(arrayList2.get(4));
+		System.out.println(arrayList2.get(5));
+		}
+		catch(IndexOutOfBoundsException e)
+		{
+			System.out.println("List is empty or cleared.");
+		}
+		System.out.println();
+		
+		ArrayList<Integer> cloneOfarrayList1 = (ArrayList<Integer>) arrayList1.clone();
+		arrayList1.clear();
+		System.out.println("Cleared arrayList1 after cloning.");
+		System.out.println("Printing clone of arrayList1:");
+		System.out.println(cloneOfarrayList1.get(0));
+		System.out.println(cloneOfarrayList1.get(1));
+		System.out.println(cloneOfarrayList1.get(2));
+		System.out.println(cloneOfarrayList1.get(3));
+		System.out.println(cloneOfarrayList1.get(4));
+		System.out.println(cloneOfarrayList1.get(5));
+		System.out.println();
+		
+		System.out.print("Does cloneOfarrayList1 contain 6?- ");
+		boolean elementExists = cloneOfarrayList1.contains(6);
+		if(elementExists)
+		{
+			System.out.println("Yes");
+		}
+		else
+		{
+			System.out.println("No");
+		}
+	}
+}
diff --git a/Vivek Parmar/Lists-Interface-and-ArrayList/MyLists.java b/Vivek Parmar/Lists-Interface-and-ArrayList/MyLists.java
new file mode 100644
index 0000000..0cf80ac
--- /dev/null
+++ b/Vivek Parmar/Lists-Interface-and-ArrayList/MyLists.java	
@@ -0,0 +1,153 @@
+package com.vivek.javacodes7;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+
+public class MyLists implements List<String>
+{
+	public static void main(String[] args) 
+	{
+		
+	}
+
+	@Override
+	public int size() {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public boolean isEmpty() {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public boolean contains(Object o) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public Iterator<String> iterator() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Object[] toArray() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public <T> T[] toArray(T[] a) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public boolean add(String e) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public boolean remove(Object o) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public boolean containsAll(Collection<?> c) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public boolean addAll(Collection<? extends String> c) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public boolean addAll(int index, Collection<? extends String> c) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public boolean removeAll(Collection<?> c) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public boolean retainAll(Collection<?> c) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public void clear() {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public String get(int index) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public String set(int index, String element) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void add(int index, String element) {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public String remove(int index) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public int indexOf(Object o) {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public int lastIndexOf(Object o) {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public ListIterator<String> listIterator() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public ListIterator<String> listIterator(int index) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public List<String> subList(int fromIndex, int toIndex) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+}
diff --git a/Vivek Parmar/Loop-&-Condition/DoWhile.java b/Vivek Parmar/Loop-&-Condition/DoWhile.java
new file mode 100644
index 0000000..7b65c84
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/DoWhile.java	
@@ -0,0 +1,16 @@
+package com.vivek.javacodes2;
+
+public class DoWhile {
+
+	public static void main(String[] args) {
+		int count = 1;
+		System.out.println("Number count is:");
+		do
+		{
+			System.out.println(count);
+			count++;
+		}
+		while(count<=10);
+	}
+
+}
diff --git a/Vivek Parmar/Loop-&-Condition/IfElseIf.java b/Vivek Parmar/Loop-&-Condition/IfElseIf.java
new file mode 100644
index 0000000..ea536a0
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/IfElseIf.java	
@@ -0,0 +1,43 @@
+package com.vivek.javacodes2;
+
+import java.util.Scanner;
+
+public class IfElseIf {
+
+	public static void main(String[] args) {
+		Scanner scanner = new Scanner(System.in);
+		System.out.print("Enter name: ");
+		String name = scanner.next();
+		System.out.print("Enter marks: ");
+		int marks = scanner.nextInt();
+		scanner.close();
+		char grade;
+		
+		if(marks>=90)
+		{
+			grade = 'A';
+		}
+		else if(marks>=80)
+		{
+			grade = 'B';
+		}
+		else if(marks>=70)
+		{
+			grade = 'C';
+		}
+		else if(marks>=60)
+		{
+			grade = 'D';
+		}
+		else if(marks>=40 && marks<60)
+		{
+			grade = 'P';
+		}
+		else
+		{
+			grade = 'F';
+		}
+		System.out.println(name + ", you got " + grade + ".");
+	}
+
+}
diff --git a/Vivek Parmar/Loop-&-Condition/If_condition.java b/Vivek Parmar/Loop-&-Condition/If_condition.java
new file mode 100644
index 0000000..f530abd
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/If_condition.java	
@@ -0,0 +1,23 @@
+package com.vivek.javacodes2;
+
+import java.util.Scanner;
+
+public class If_condition 
+{
+	public static void main(String[] args) 
+	{
+		Scanner scanner = new Scanner(System.in);
+		System.out.print("Enter age: ");
+		int num = scanner.nextInt();
+		scanner.close();
+		if(num>=18)
+		{
+			System.out.println("You can vote.");
+		}
+		else
+		{
+			System.out.println("You can not vote.");
+		}
+	}
+
+}
diff --git a/Vivek Parmar/Loop-&-Condition/If_nested.java b/Vivek Parmar/Loop-&-Condition/If_nested.java
new file mode 100644
index 0000000..075868a
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/If_nested.java	
@@ -0,0 +1,24 @@
+package com.vivek.javacodes2;
+
+public class If_nested 
+{
+	public static void main(String[] args) 
+	{
+		int i=5, j=27;
+		if(i<j)
+		{
+			if(j>1)
+			{
+				System.out.println("i and j: " + i + " & " + j);
+			}
+			else 
+			{
+				System.out.println("j is lesser than 1.");
+			}
+		}
+		else
+		{
+			System.out.println("i is greater than j.");
+		}
+	}
+}
diff --git a/Vivek Parmar/Loop-&-Condition/NestedWhile.java b/Vivek Parmar/Loop-&-Condition/NestedWhile.java
new file mode 100644
index 0000000..cbf0a31
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/NestedWhile.java	
@@ -0,0 +1,34 @@
+package com.vivek.javacodes2;
+
+public class NestedWhile {
+
+	public static void main(String[] args) {
+		int i=1;
+		int j=1;
+		
+		while(i<=8)
+		{
+			while(j<=8)
+			{
+				System.out.print(j);
+				j++;
+			}
+			i++;
+			System.out.println();
+			j=1;
+		}
+
+//		while(i<=8)
+//		{
+//			while(j<=8)
+//			{
+//				System.out.print(i);
+//				j++;
+//			}
+//			i++;
+//			System.out.println();
+//			j=1;
+//		}
+	}
+
+}
diff --git a/Vivek Parmar/Loop-&-Condition/Nested_loop.java b/Vivek Parmar/Loop-&-Condition/Nested_loop.java
new file mode 100644
index 0000000..d527297
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/Nested_loop.java	
@@ -0,0 +1,19 @@
+package com.vivek.javacodes2;
+
+public class Nested_loop 
+{
+	public static void main(String[] args) 
+	{
+		System.out.println("i     j");
+		System.out.println("-------");
+		for(int i=1; i<=3; i++) 
+		{
+			for(int j=1; j<=5; j++) 
+			{
+				System.out.println(i + "     " + j);
+			}
+			System.out.println("-------");
+			System.out.println("-------");
+		}
+	}
+}
diff --git a/Vivek Parmar/Loop-&-Condition/Pattern.java b/Vivek Parmar/Loop-&-Condition/Pattern.java
new file mode 100644
index 0000000..0897291
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/Pattern.java	
@@ -0,0 +1,24 @@
+package com.vivek.javacodes2;
+
+import java.util.Scanner;
+
+public class Pattern {
+
+	public static void main(String[] args) {
+		
+		Scanner scanner = new Scanner(System.in);
+		System.out.print("Enter the row(s): ");
+		int rows = scanner.nextInt();
+		scanner.close();
+		
+		for(int i=1; i<=rows; i++)
+		{
+			for(int j=1; j<=i; j++)
+			{
+				System.out.print("@");
+			}
+			System.out.println();
+		}
+	}
+
+}
diff --git a/Vivek Parmar/Loop-&-Condition/Read_Input.java b/Vivek Parmar/Loop-&-Condition/Read_Input.java
new file mode 100644
index 0000000..dc6c309
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/Read_Input.java	
@@ -0,0 +1,28 @@
+package com.vivek.javacodes2;
+
+import java.util.Scanner;
+
+public class Read_Input {
+
+	public static void main(String[] args) {
+		
+		Scanner scanner = new Scanner(System.in);
+		System.out.print("Enter the number of elements you want to store: ");
+		int numsOfElements = scanner.nextInt();
+		
+		int[] storageArray = new int[numsOfElements]; 
+		System.out.println("Enter the elements of the array: ");
+		for(int i=0; i<numsOfElements; i++) 
+		{
+			storageArray[i] = scanner.nextInt();
+		}
+		scanner.close();
+		
+		System.out.println("Array elements: ");
+		for(int i=0; i<numsOfElements; i++)
+		{
+			System.out.println(storageArray[i]);
+		}
+	}
+
+}
diff --git a/Vivek Parmar/Loop-&-Condition/TwoDimensionsArray.java b/Vivek Parmar/Loop-&-Condition/TwoDimensionsArray.java
new file mode 100644
index 0000000..c29d254
--- /dev/null
+++ b/Vivek Parmar/Loop-&-Condition/TwoDimensionsArray.java	
@@ -0,0 +1,36 @@
+package com.vivek.javacodes2;
+
+import java.util.Scanner;
+
+public class TwoDimensionsArray {
+
+	public static void main(String[] args) {
+		
+		System.out.println("Enter 2D array size: ");
+		Scanner scanner = new Scanner(System.in);
+		int rows = scanner.nextInt();
+		int columns = scanner.nextInt();
+		
+		System.out.println("Enter array elements: ");
+		int storage2DArray[][] = new int[rows][columns];
+		for(int i=0; i<rows; i++)
+		{
+			for(int j=0; j<columns; j++)
+			{
+				storage2DArray[i][j] = scanner.nextInt();
+			}
+		}
+		scanner.close();
+		
+		System.out.println("Entered Data: ");
+		for(int[] x:storage2DArray)
+		{
+			for(int y:x)
+			{
+				System.out.print(y + " ");
+			}
+			System.out.println();
+		}
+	}
+
+}
diff --git a/Vivek Parmar/Method Concept/Method.java b/Vivek Parmar/Method Concept/Method.java
new file mode 100644
index 0000000..c1a2b12
--- /dev/null
+++ b/Vivek Parmar/Method Concept/Method.java	
@@ -0,0 +1,18 @@
+package com.vivek.javacodes;
+
+public class Method {
+
+	public static void main(String[] args) {
+		
+		int a = 2;
+		int b = 3;
+		float product = a*b;
+		System.out.println("Method: " + product);	
+		Method_2 obj1 = new Method_2();
+		System.out.println("Method-2: " + obj1.main(args));
+		System.out.println("Method-2: " + Method_2.main(args));
+		Method_4 obj2 = new Method_4();
+		System.out.println("Method-3: " + Method_3.main(args));
+		System.out.println("Method-4: " + obj2.name);
+	}
+}
diff --git a/Vivek Parmar/Method Concept/Method_2.java b/Vivek Parmar/Method Concept/Method_2.java
new file mode 100644
index 0000000..a328608
--- /dev/null
+++ b/Vivek Parmar/Method Concept/Method_2.java	
@@ -0,0 +1,13 @@
+package com.vivek.javacodes;
+
+public class Method_2 {
+
+	public static int main(String[] args) {
+			
+		int a = 5;
+		int b = 6;
+		int sum = a+b;
+		System.out.println("Method-2: " + sum);
+		return sum+1;
+	}
+}
diff --git a/Vivek Parmar/Method Concept/Method_3.java b/Vivek Parmar/Method Concept/Method_3.java
new file mode 100644
index 0000000..a3d1dda
--- /dev/null
+++ b/Vivek Parmar/Method Concept/Method_3.java	
@@ -0,0 +1,11 @@
+package com.vivek.javacodes;
+
+public class Method_3 {
+
+	public static boolean main(String[] args) {
+		String name = "VivekP";
+		System.out.println("Method-3: " + name);
+		return false;
+	}
+
+}
diff --git a/Vivek Parmar/Method Concept/Method_4.java b/Vivek Parmar/Method Concept/Method_4.java
new file mode 100644
index 0000000..93ac26a
--- /dev/null
+++ b/Vivek Parmar/Method Concept/Method_4.java	
@@ -0,0 +1,7 @@
+package com.vivek.javacodes;
+
+class Method_4 {
+
+	String name = "VivekParmar";
+
+}
diff --git a/Vivek Parmar/Method Concept/Method_5.java b/Vivek Parmar/Method Concept/Method_5.java
new file mode 100644
index 0000000..1903140
--- /dev/null
+++ b/Vivek Parmar/Method Concept/Method_5.java	
@@ -0,0 +1,13 @@
+package com.vivek.javacodes;
+
+public class Method_5 {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		System.out.println("Args: ");
+		for(String arg: args) {
+			System.out.println(arg);
+		}
+	}
+
+}
diff --git a/Vivek Parmar/MySpliterator.java b/Vivek Parmar/MySpliterator.java
new file mode 100644
index 0000000..474a7a0
--- /dev/null
+++ b/Vivek Parmar/MySpliterator.java	
@@ -0,0 +1,34 @@
+package com.vivek.javacodes7;
+
+import java.util.ArrayList;
+import java.util.Spliterator;
+
+public class MySpliterator 
+{
+	public static void main(String[] args) 
+	{
+		ArrayList<String> fbPosts = new ArrayList<String>();
+		
+		fbPosts.add("Post1");
+		fbPosts.add("Post2");
+		fbPosts.add("Post3");
+		fbPosts.add("Post4");
+		fbPosts.add("Post5");
+		fbPosts.add("Post6");
+		
+		Spliterator<String> spliterator1 = fbPosts.spliterator();
+		Spliterator<String> spliterator2 = spliterator1.trySplit();
+		
+		System.out.println("SPL1 estimated size of data: " + spliterator1.estimateSize());
+		System.out.println("SPL1 exact size: " + spliterator1.getExactSizeIfKnown());
+		spliterator1.forEachRemaining(System.out::println);
+		System.out.println("SPL1 estimated size of data: " + spliterator1.estimateSize());
+		System.out.println("SPL1 exact size: " + spliterator1.getExactSizeIfKnown());
+
+		System.out.println("SPL2 estimated size of data: " + spliterator2.estimateSize());
+		System.out.println("SPL2 exact size: " + spliterator2.getExactSizeIfKnown());
+		spliterator2.forEachRemaining(System.out::println);
+		System.out.println("SPL2 estimated size of data: " + spliterator2.estimateSize());
+		System.out.println("SPL2 exact size: " + spliterator2.getExactSizeIfKnown());
+	}
+}
diff --git a/Vivek Parmar/MyTreeTest.java b/Vivek Parmar/MyTreeTest.java
new file mode 100644
index 0000000..bbc0649
--- /dev/null
+++ b/Vivek Parmar/MyTreeTest.java	
@@ -0,0 +1,75 @@
+package com.vivek.javacodes7;
+
+public class MyTreeTest 
+{
+    public static void main(String[] args) 
+    {
+        Tree tree = new Tree();
+        Tree.Node root = new Tree.Node(5);
+        
+        tree.insert(root, 2);
+        tree.insert(root, 4);
+        tree.insert(root, 8);
+        tree.insert(root, 6);
+        tree.insert(root, 7);
+        tree.insert(root, 3);
+        tree.insert(root, 9);
+        
+        System.out.println("Traverse the tree: ");
+        tree.traverseInOrder(root);
+    }
+    
+    public static class Tree
+    {
+        static class Node
+        {
+            int value;
+            Node left, right;
+            
+            Node(int value)
+            {
+                this.value = value;
+                left = null;
+                right = null;
+            }
+        }
+        
+        public void insert(Node node, int value)
+        {
+            if(value < node.value)
+            {
+                if(node.left != null)
+                {
+                insert(node.left, value);
+                }
+                else
+                {
+                    System.out.println("Insert " + value + " to the left of " + node.value);
+                    node.left = new Node(value);
+                }
+            }
+            else if(value > node.value)
+            {
+                if(node.right != null)
+                {
+                    insert(node.right, value);
+                }
+                else
+                {
+                    node.right = new Node(value);
+                    System.out.println("Inserted " + value + " to the right of " + node.value);
+                }
+            }
+        }
+        
+        public void traverseInOrder(Node node)
+        {
+            if(node != null)
+            {
+                traverseInOrder(node.left);
+                System.out.println(" " + node.value);
+                traverseInOrder(node.right);
+            }
+        }
+    }
+}
diff --git a/Vivek Parmar/MyTreeTest2.java b/Vivek Parmar/MyTreeTest2.java
new file mode 100644
index 0000000..3fe650f
--- /dev/null
+++ b/Vivek Parmar/MyTreeTest2.java	
@@ -0,0 +1,101 @@
+package com.vivek.javacodes7;
+
+public class MyTreeTest2
+{
+    public static void main(String[] args) 
+    {
+        Tree tree = new Tree();
+        Tree.Node root = new Tree.Node(5);
+        
+        tree.insert(root, 2);
+        tree.insert(root, 4);
+        tree.insert(root, 8);
+        tree.insert(root, 6);
+        tree.insert(root, 7);
+        tree.insert(root, 3);
+        tree.insert(root, 9);
+        
+        System.out.println("Traverse the tree: ");
+        tree.traverseInOrder(root);
+
+        System.out.println("Traverse PreOrder: ");
+        tree.traversePreOrder(root);
+
+        System.out.println("Traverse PostOrder: ");
+        tree.traversePostOrder(root);
+    }
+    
+    public static class Tree
+    {
+        static class Node
+        {
+            int value;
+            Node left, right;
+            
+            Node(int value)
+            {
+                this.value = value;
+                left = null;
+                right = null;
+            }
+        }
+        
+        public void insert(Node node, int value)
+        {
+            if(value < node.value)
+            {
+                if(node.left != null)
+                {
+                insert(node.left, value);
+                }
+                else
+                {
+                    System.out.println("Insert " + value + " to the left of " + node.value);
+                    node.left = new Node(value);
+                }
+            }
+            else if(value > node.value)
+            {
+                if(node.right != null)
+                {
+                    insert(node.right, value);
+                }
+                else
+                {
+                    node.right = new Node(value);
+                    System.out.println("Inserted " + value + " to the right of " + node.value);
+                }
+            }
+        }
+        
+        public void traverseInOrder(Node node)
+        {
+            if(node != null)
+            {
+                traverseInOrder(node.left);
+                System.out.println(" " + node.value);
+                traverseInOrder(node.right);
+            }
+        }
+
+        public void traversePreOrder(Node node)
+        {
+            if(node != null)
+            {
+                System.out.println(" " + node.value);
+                traversePreOrder(node.left);
+                traversePreOrder(node.right);
+            }
+        }
+
+        public void traversePostOrder(Node node)
+        {
+            if ((node != null))
+            {
+                traversePostOrder(node.left);
+                traversePostOrder(node.right);
+                System.out.println(" " + node.value);
+            }
+        }
+    }
+}
diff --git a/Vivek Parmar/MyTreeTest3.java b/Vivek Parmar/MyTreeTest3.java
new file mode 100644
index 0000000..81875ed
--- /dev/null
+++ b/Vivek Parmar/MyTreeTest3.java	
@@ -0,0 +1,154 @@
+package com.vivek.javacodes7;
+
+public class MyTreeTest3 
+{
+     public static void main(String[] args) 
+    {
+        Tree tree = new Tree();
+        Tree.Node root = new Tree.Node(5);
+        
+        tree.insert(root, 2);
+        tree.insert(root, 4);
+        tree.insert(root, 8);
+        tree.insert(root, 6);
+        tree.insert(root, 7);
+        tree.insert(root, 3);
+        tree.insert(root, 9);
+        
+        System.out.println("Traverse the tree: ");
+        tree.traverseInOrder(root);
+
+        System.out.println("Traverse PreOrder: ");
+        tree.traversePreOrder(root);
+
+        System.out.println("Traverse PostOrder: ");
+        tree.traversePostOrder(root);
+        
+        System.out.println("Breadth First Search / Level Order: ");
+        tree.bfs(root);
+    }
+    
+    public static class Tree
+    {
+        static class Node
+        {
+            int value;
+            Node left, right;
+            
+            Node(int value)
+            {
+                this.value = value;
+                left = null;
+                right = null;
+            }
+        }
+        
+        public void insert(Node node, int value)
+        {
+            if(value < node.value)
+            {
+                if(node.left != null)
+                {
+                insert(node.left, value);
+                }
+                else
+                {
+                    System.out.println("Insert " + value + " to the left of " + node.value);
+                    node.left = new Node(value);
+                }
+            }
+            else if(value > node.value)
+            {
+                if(node.right != null)
+                {
+                    insert(node.right, value);
+                }
+                else
+                {
+                    node.right = new Node(value);
+                    System.out.println("Inserted " + value + " to the right of " + node.value);
+                }
+            }
+        }
+        
+        public void traverseInOrder(Node node)
+        {
+            if(node != null)
+            {
+                traverseInOrder(node.left);
+                System.out.println(" " + node.value);
+                traverseInOrder(node.right);
+            }
+        }
+
+        public void traversePreOrder(Node node)
+        {
+            if(node != null)
+            {
+                System.out.println(" " + node.value);
+                traversePreOrder(node.left);
+                traversePreOrder(node.right);
+            }
+        }
+
+        public void traversePostOrder(Node node)
+        {
+            if ((node != null))
+            {
+                traversePostOrder(node.left);
+                traversePostOrder(node.right);
+                System.out.println(" " + node.value);
+            }
+        }
+        
+        public int height(Node root)
+        {
+            if(root == null)
+            {
+                return 0;
+            }
+            else
+            {
+                int lheight = height(root.left);
+                int rheight = height(root.right);
+                
+                if(lheight > rheight)
+                {
+                    return(lheight+1);
+                }
+                else
+                {
+                    return(rheight+1);
+                }
+            }
+        }
+        
+        public void printCurrentLevel(Node root, int level)
+        {
+            if(root == null)
+            {
+                return;
+            }
+            
+            if(level == 1)
+            {
+                System.out.println(root.value + " ");
+            }
+            else if(level > 1)
+            {
+                printCurrentLevel(root.left, level-1);
+                printCurrentLevel(root.right, level-1);
+            }
+        }
+        
+        public void bfs(Node root)
+        {
+            int h = height(root);
+            
+            for(int i=1; i<=h; i++)
+            {
+                printCurrentLevel(root, i);
+            }
+        }
+    }
+}
diff --git a/Vivek Parmar/NestedWhile.java b/Vivek Parmar/NestedWhile.java
new file mode 100644
index 0000000..ce9734c
--- /dev/null
+++ b/Vivek Parmar/NestedWhile.java	
@@ -0,0 +1,19 @@
+package com.vivek.javacodes;
+
+public class NestedWhile {
+
+	public static void main(String[] args) {
+		
+		int col = 1;
+		int row = 1;
+		while(col<=10) {
+			while(row<=5) {
+				System.out.print("*");
+				row++;
+			}
+			col++;
+			System.out.print("\n"); //System.out.println("");
+			row = 1;
+		}
+	}
+}
\ No newline at end of file
diff --git a/Vivek Parmar/NodeTest.java b/Vivek Parmar/NodeTest.java
new file mode 100644
index 0000000..bd1b30a
--- /dev/null
+++ b/Vivek Parmar/NodeTest.java	
@@ -0,0 +1,26 @@
+package code.vivek.javacodes7;
+
+public class NodeTest 
+{
+    public static void main(String[] args) 
+    {
+       Node node = new Node(5);
+       node.left = new Node(0);
+       node.right = new Node(10);
+       System.out.println()
+    }
+    
+    static class Node
+    {
+        int value;
+        
+        Node left, right;
+        
+        Node(int value)
+        {
+            this.value = value;
+            left = null;
+            right = null;
+        }
+    }
+}
diff --git a/Vivek Parmar/Overloading1.java b/Vivek Parmar/Overloading1.java
new file mode 100644
index 0000000..b2221c1
--- /dev/null
+++ b/Vivek Parmar/Overloading1.java	
@@ -0,0 +1,14 @@
+package com.vivek.javacodes3;
+
+public class Overloading1 
+{
+	public void display(char c)
+	{
+		System.out.println(c);
+	}
+	
+	public void display(char c, int num)
+	{
+		System.out.println(c + " " + num);
+	}
+}
diff --git a/Vivek Parmar/Overloading2.java b/Vivek Parmar/Overloading2.java
new file mode 100644
index 0000000..c267940
--- /dev/null
+++ b/Vivek Parmar/Overloading2.java	
@@ -0,0 +1,11 @@
+package com.vivek.javacodes3;
+
+public class Overloading2 {
+
+	public static void main(String[] args) {
+		Overloading1 obj = new Overloading1();
+		obj.display('O');
+		obj.display('O', 0);
+	}
+
+}
diff --git a/Vivek Parmar/Priority Queues/MyComparator.java b/Vivek Parmar/Priority Queues/MyComparator.java
new file mode 100644
index 0000000..e615ea7
--- /dev/null
+++ b/Vivek Parmar/Priority Queues/MyComparator.java	
@@ -0,0 +1,21 @@
+package com.vivek.javacodes7;
+
+import java.util.Comparator;
+
+public class MyComparator implements Comparator<Integer> 
+{
+
+	@Override
+	public int compare(Integer o1, Integer o2) {
+		
+		if(o1 >= o2)
+		{
+			return o1;
+		}
+		else
+		{
+			return o2;
+		}
+	}
+	
+}
diff --git a/Vivek Parmar/Priority Queues/MyPriorityQueue.java b/Vivek Parmar/Priority Queues/MyPriorityQueue.java
new file mode 100644
index 0000000..e333c9c
--- /dev/null
+++ b/Vivek Parmar/Priority Queues/MyPriorityQueue.java	
@@ -0,0 +1,41 @@
+package com.vivek.javacodes7;
+
+import java.util.Iterator;
+import java.util.PriorityQueue;
+
+public class MyPriorityQueue 
+{
+	public static void main(String[] args) 
+	{
+		PriorityQueue<Integer> pq1 = new PriorityQueue<Integer>(); 
+		System.out.println("Is 'pq' empty?- " + pq1.isEmpty());
+	
+		
+		MyComparator mComp = new MyComparator();
+		PriorityQueue<Integer> pq2 = new PriorityQueue<Integer>(mComp);
+		
+		pq1.add(10);
+		pq2.add(10);
+		
+		pq1.add(5);
+		pq2.add(5);
+		
+		pq1.add(100);
+		pq2.add(100);
+		
+		Iterator<Integer> pqIter1 = pq1.iterator();
+		Iterator<Integer> pqIter2 = pq2.iterator();
+		
+		System.out.println("PQ1 Priority Queue:");
+		while(pqIter1.hasNext())
+		{
+			System.out.println(pqIter1.next());
+		}
+		
+		System.out.println("PQ2 Priority Queue:");
+		while(pqIter2.hasNext())
+		{
+			System.out.println(pqIter2.next());
+		}
+	}
+}
diff --git a/Vivek Parmar/Single and Multiple Inheritence/BMIMachine.java b/Vivek Parmar/Single and Multiple Inheritence/BMIMachine.java
new file mode 100644
index 0000000..e359bc4
--- /dev/null
+++ b/Vivek Parmar/Single and Multiple Inheritence/BMIMachine.java	
@@ -0,0 +1,17 @@
+package com.vivek.javacodes7;
+
+public class BMIMachine extends HeartMonitor
+{
+    public static void main(String[] args)
+    {
+        System.out.println(getMaxHeartRate(30));
+    }
+
+    public static int getMaxHeartRate(int age) 
+    {
+        int result;
+        result = 230-age;
+        System.out.println("___Method executed from Sub-class___");
+        return result;
+    }
+}
diff --git a/Vivek Parmar/Single and Multiple Inheritence/HeartMonitor.java b/Vivek Parmar/Single and Multiple Inheritence/HeartMonitor.java
new file mode 100644
index 0000000..d528c23
--- /dev/null
+++ b/Vivek Parmar/Single and Multiple Inheritence/HeartMonitor.java	
@@ -0,0 +1,17 @@
+package com.vivek.javacodes7;
+
+public class HeartMonitor 
+{
+    public static void main(String[] args)
+    {
+        System.out.println(getMaxHeartRate(30));
+    }
+
+    public static int getMaxHeartRate(int age) 
+    {
+        int result;
+        result = 220-age;
+        System.out.println("___Method executed from Base-class___");
+        return result;
+    }
+}
diff --git a/Vivek Parmar/Stacks-Queues-and-ArrayDeque/MyStack.java b/Vivek Parmar/Stacks-Queues-and-ArrayDeque/MyStack.java
new file mode 100644
index 0000000..f929ccc
--- /dev/null
+++ b/Vivek Parmar/Stacks-Queues-and-ArrayDeque/MyStack.java	
@@ -0,0 +1,29 @@
+package com.vivek.javacodes7;
+
+import java.util.Stack;
+
+public class MyStack 
+{
+	public static void main(String[] args) 
+	{
+		Stack<Integer> intStack = new Stack<Integer>();
+		System.out.println("Is Stack empty? - " + intStack.empty());
+		
+		intStack.push(10);
+		intStack.push(20);
+		System.out.println("Get the top element: " + intStack.peek());
+		boolean elementExists = false;
+		if(intStack.search(20)>0)
+		{
+			elementExists = true;
+		}
+		else
+		{
+			elementExists = false;
+		}
+		System.out.println("Does Stack contains 20? - " + elementExists);
+		intStack.pop();
+		System.out.println("Top element after pop: " + intStack.peek());
+	}
+
+}
diff --git a/Vivek Parmar/Stacks-Queues-and-ArrayDeque/StackUsingDeque.java b/Vivek Parmar/Stacks-Queues-and-ArrayDeque/StackUsingDeque.java
new file mode 100644
index 0000000..dcc5648
--- /dev/null
+++ b/Vivek Parmar/Stacks-Queues-and-ArrayDeque/StackUsingDeque.java	
@@ -0,0 +1,31 @@
+package com.vivek.javacodes7;
+
+import java.util.ArrayDeque;
+import java.util.Iterator;
+
+public class StackUsingDeque 
+{
+	public static void main(String[] args)
+	{
+		ArrayDeque<String> myDeque = new ArrayDeque<String>();
+		
+		myDeque.add("Vivek");
+		System.out.println("1.First Element: " + myDeque.getFirst());
+		myDeque.addFirst("Subhav");
+		System.out.println("2.First Element(Updated): " + myDeque.getFirst());
+		myDeque.addLast("Roham");
+		myDeque.offerFirst("Naman");
+		myDeque.offer("Aaran");
+		System.out.println("3.First Element(Updated): " + myDeque.getFirst());
+		System.out.println("4.Last Element: " + myDeque.getLast());
+		System.out.println("5.Deque contains 'Subhav'?: " + myDeque.contains("Subhav"));
+		System.out.println("6.Iterating all elements in descending order: ");
+		
+		Iterator<String> myIterator = myDeque.descendingIterator();
+		while(myIterator.hasNext())
+		{
+			System.out.println("  " + myIterator.next());
+		}
+	}
+
+}
diff --git a/Vivek Parmar/StringOperation.java b/Vivek Parmar/StringOperation.java
new file mode 100644
index 0000000..a04c8aa
--- /dev/null
+++ b/Vivek Parmar/StringOperation.java	
@@ -0,0 +1,28 @@
+package com.vivek.javacodes;
+
+public class StringOperation {
+
+	public static void main(String[] args) {
+		
+		String name = " Vivek Parmar ";
+		String firstName = "Vivek";
+		String lastName = "Parmar";
+		
+		System.out.println("Name: " + name.strip());
+		System.out.println("Username: " + firstName.concat(lastName+7));
+		if(name.contains(firstName) && name.contains(lastName)) {
+			System.out.println("First Name: " + firstName);
+			System.out.println("Last Name: " + lastName);
+		}
+		
+		System.out.println();
+		
+		System.out.println("Length of first name: " + firstName.length());
+		System.out.println("Length of last name: " + lastName.length());
+		
+		System.out.println("");
+		System.out.println("FIRST NAME: " + firstName.toUpperCase());
+		System.out.println("last name: " + lastName.toLowerCase());
+		
+	}
+}
diff --git a/Vivek Parmar/ThrowException.java b/Vivek Parmar/ThrowException.java
new file mode 100644
index 0000000..f49724c
--- /dev/null
+++ b/Vivek Parmar/ThrowException.java	
@@ -0,0 +1,30 @@
+package com.vivek.javacodes6;
+
+import java.util.Scanner;
+
+public class ThrowException 
+{
+
+	public static void main(String[] args) 
+	{
+		Scanner scanner = new Scanner(System.in);
+		
+		System.out.print("Please enter your age: ");
+		int age = scanner.nextInt();
+		
+		if(age <= 0)
+		{
+			throw new NumberFormatException();
+		}
+		else if(age >= 120) 
+		{
+			throw new NumberFormatException();
+		}
+		
+		System.out.println("->Your maximum Heart-rate is " + (220 - age) + ".");
+		
+		scanner.close();
+	}
+
+}
+
diff --git a/Vivek Parmar/ToArray.java b/Vivek Parmar/ToArray.java
new file mode 100644
index 0000000..0de9287
--- /dev/null
+++ b/Vivek Parmar/ToArray.java	
@@ -0,0 +1,19 @@
+package com.vivek.javacodes7;
+
+import java.util.ArrayList;
+
+public class ToArray 
+{
+	public static void main(String[] args) 
+	{
+		ArrayList<String> students = new ArrayList<String>();
+		students.add("Vivek");
+		students.add("Yadu");
+		students.add("Surya");
+		
+		Object[] arrayOfStudents = students.toArray();
+		System.out.println("Element at Index 0 for Array: " + arrayOfStudents[0]);
+		System.out.println("HashCode of the array: " + arrayOfStudents.hashCode());
+	}
+
+}
diff --git a/Vivek Parmar/TryCatchFinally.java b/Vivek Parmar/TryCatchFinally.java
new file mode 100644
index 0000000..cdbde83
--- /dev/null
+++ b/Vivek Parmar/TryCatchFinally.java	
@@ -0,0 +1,47 @@
+package com.vivek.javacodes6;
+
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+public class TryCatchFinally 
+{
+	public static void main(String[] args) 
+	{
+		try 
+		{
+			Scanner scanner = new Scanner(System.in);
+			
+			System.out.print("Enter No.1: ");
+			int num1 = scanner.nextInt();
+			
+			System.out.print("Enter No.2: ");
+			int num2 = scanner.nextInt();
+			
+			int num3 = sum(num1, num2);
+			System.out.println("The answer is " + num3 + ".");
+			scanner.close();
+		}
+		catch(InputMismatchException e) 
+		{
+			System.out.println("Please enter only numbers.");
+		}
+	}
+	
+	private static int sum(int a, int b) 
+	{
+		int num4 = 0;
+		
+		try
+		{
+			num4 = a+b;
+		}
+		catch(Exception e)
+		{
+			System.out.println("There is an error in calculation.");
+		}
+		finally {
+			System.out.println("->'finally' executed.");
+			return num4;
+		}
+	}
+}
diff --git a/Vivek Parmar/VariableDatatype.java b/Vivek Parmar/VariableDatatype.java
new file mode 100644
index 0000000..ffdfc38
--- /dev/null
+++ b/Vivek Parmar/VariableDatatype.java	
@@ -0,0 +1,49 @@
+package com.vivek.javacodes;
+
+public class VariableDatatype {
+
+	public static void main(String[] args) {
+		
+		String StringVal = "Datatypes:";
+		System.out.println(StringVal);
+		
+		byte byteVal = 50; 
+		System.out.println("1. byte: 'byte' can store whole numbers from -128 to 127.");
+		System.out.println("Example: " + byteVal + "\n");
+		
+		short shortVal = 25000;
+		System.out.println("2. short: 'short' can store whole numbers from -32768 to 32767.");
+		System.out.println("Example: " + shortVal + "\n");
+		
+		int intVal = 100000;
+		System.out.println("3. int: 'int' can store whole numbers from -2^31 to (2^31 -1).");
+		System.out.println("Example: " + intVal + "\n");
+		
+		long longVal = 100_000_000L;
+		System.out.println("4. long: 'long' can store whole numbers from -2^63 to (2^63 -1).");
+		System.out.println("Example: " + longVal + "\n");
+		
+		float floatVal1 = 20.6633f;
+		float floatVal2 = 10.3333f;
+		float floatVal = floatVal1*floatVal2;
+		System.out.println("5. float: 'float' can store numbers from 6 to 7 decimal digits.");
+		System.out.println("Example: " + floatVal + "\n");
+		
+		double doubleVal1 = 20.6666D;
+		double doubleVal2 = 10.3333d;
+		double doubleVal = doubleVal1*doubleVal2;
+		System.out.println("6. double: 'double' can store numbers til 15 decimal digits.");
+		System.out.println("Example: " + doubleVal + "\n");
+		
+		boolean booleanVal = true;
+		if(booleanVal) {
+			System.out.println("7. boolean: 'boolean' can store 'true' or 'false' values.");
+			System.out.println("Example: " + booleanVal + "\n");
+		}
+		
+		char charVal = 'V';
+		System.out.println("8. char: 'char' can store single character.");
+		System.out.println("Example: " + charVal + "\n");
+	}
+
+}