JP01.java

import java.util.Scanner

JP02.java

package calculation;

public class Calculator {
    public int add(int a, int b) {
        return a + b;
    }

    public static void main(String args[]) {
        Calculator obj = new Calculator();
        System.out.println(obj.add(10, 20));
    }
} 

JP03.java

//Java Program to import the package
//which was created earlier

import calculation.Calculator;

public class Calculate {
    public static void main(String args[]) {
        Calculator obj = new Calculator();
        System.out.println(obj.add(100, 200));
    }
} 

JP04.java

import calculation.*

JP05.java

package abcpackage;

public class Addition {
    //Since we didn't mention any access modifier here, it would
    //be considered as default.
    int addTwoNumbers(int a, int b) {
        return a + b;
    }
} 

JP06.java

package xyzpackage;

import abcpackage.*;

public class Test {
    public static void main(String args[]) {
        Addition ob = new Addition();
        //It will throw error because we are trying to access
        //the default method in another package         
        ob.addTwoNumbers(10, 21);
    }
}   

JP07.java

class ABC {
    private double num = 100;

    private int square(int a) {
        return a * a;
    }
}

public class Test {
    public static void main(String args[]) {
        ABC obj = new ABC();
        System.out.println(obj.num);
        System.out.println(obj.square(10));
    }
}

JP08.java

package abcpackage;

public class Addition {
    protected int addTwoNumbers(int a, int b) {
        return a + b;
    }
}  

JP09.java

package xyzpackage;

import abcpackage.*;

class Test extends Addition {
    public static void main(String args[]) {
        Test obj = new Test();
        System.out.println(obj.addTwoNumbers(18, 42));
    }
}  

JP10.java

package abcpackage;

public class Addition {
    public int addTwoNumbers(int a, int b) {
        return a + b;
    }
}  

JP11.java

package xyzpackage;

import abcpackage.*;

class Test {
    public static void main(String args[]) {
        Addition obj = new Addition();
        System.out.println(obj.addTwoNumbers(18, 42));
    }
} 

JP12.java

// A Java program to demonstrate random number generation
// using java.util.Random;

import java.util.Random;

public class RandomIntegers {

    public static void main(String args[]) {
        // create instance of Random class
        Random rand = new Random();

        // Generate random integers
        int rand_int1 = rand.nextInt();

        // Print random integers
        System.out.println("Random Integers: " + rand_int1);

    }
} 

JP13.java

// Java program to demonstrate working of
// Math.random() to generate random numbers

public class RandomIntegers {
    public static void main(String args[]) {
        // Generating random doubles
        System.out.println("Random doubles: " + Math.random());
    }
}  

JP14.java

// Java program to demonstrate working of ThreadLocalRandom
// to generate random numbers.

import java.util.concurrent.ThreadLocalRandom;

public class RandomIntegers {
    public static void main(String args[]) {
        // Generate random integers
        int rand_int1 = ThreadLocalRandom.current().nextInt();

        // Print random integers
        System.out.println("Random Integers: " + rand_int1);

        // Generate Random doubles
        double rand_dub1 = ThreadLocalRandom.current().nextDouble();

        // Print random doubles
        System.out.println("Random Doubles: " + rand_dub1);

        // Generate random booleans
        boolean rand_bool1 = ThreadLocalRandom.current().nextBoolean();

        // Print random Booleans
        System.out.println("Random Booleans: " + rand_bool1);
    }
}

JP15.java

//Generating Random number
//within a given range

import java.util.Random;

public class RandomIntegers {
    public static void main(String args[]) {
        Random rand = new Random();

        // Obtain a number between [0 - 49].
        int n = rand.nextInt(50);
        System.out.println("Random Number: " + n);
    }
} 

JP16.java

for(data_type variable_name : array_name)
{
    //body of for-each loop.	                           
} 

JP17.java

class for_each {
    public static void main(String args[]) {
        int a[] = {2, 3, 4, 5, 6};
        int total = 0;
        for (int x : a) {
            total = total + x;
        }
        System.out.println("Total Sum = " + total);
    }
}

JP18.java

import java.util.ArrayList;

class for_each {
    public static void main(String args[]) {
        ArrayList<String> list = new ArrayList<>();
        list.add("Ron");
        list.add("Harry");
        list.add("Shaun");
        for (String str : list) {
            System.out.println(str);
        }
    }
}  

JP19.java

String s = �Hello�;

JP20.java

String s = new String (“Hello”);

JP21.java

/*Java program to demonstrate difference between String, 
    StringBuilder and StringBuffer */
class HelloWorld {
    // Concatenation using String 
    public static void concat1(String s1) {
        s1 = s1 + "World";
    }

    // Concatenation using StringBuilder 
    public static void concat2(StringBuilder s2) {
        s2.append("World");
    }

    // Concatenation using StringBuffer 
    public static void concat3(StringBuffer s3) {
        s3.append("World");
    }

    public static void main(String[] args) {
        String s1 = "Hello";
        concat1(s1); // s1 is not changed 
        System.out.println("String: " + s1);

        StringBuilder s2 = new StringBuilder("Hello");
        concat2(s2); // s2 is changed 
        System.out.println("StringBuilder: " + s2);

        StringBuffer s3 = new StringBuffer("Hello");
        concat3(s3); // s3 is changed 
        System.out.println("StringBuffer: " + s3);
    }
}

JP22.java

/* Java program to Reverse a String by
       converting string to characters one
       by one from the end */

import java.util.Scanner;

// Class of ReverseString
public class ReverseString {
    public static void main(String[] args) {
        //Input String from the user
        System.out.println("Enter string to reverse:");

        Scanner read = new Scanner(System.in);
        String str = read.nextLine();
        String reverse = "";


        for (int i = str.length() - 1; i >= 0; i--) {
                /*Reading and storing each character
                  individually from the end */
            reverse = reverse + str.charAt(i);
        }

        System.out.println("Reversed string is:");
        System.out.println(reverse);
    }
}

JP23.java

/* Java program to Reverse a String  by 
       converting string to characters  one 
       by one */

import java.lang.*;
import java.io.*;
import java.util.*;

// Class of ReverseString 
class ReverseString {
    public static void main(String[] args) {
        String input = "Welcome Home";
                                               
            /* convert String to character array 
               by using toCharArray */
        char[] str = input.toCharArray();

        for (int i = str.length - 1; i >= 0; i--)
            System.out.print(str[i]);
    }
}

JP24.java

// Java program to ReverseString using StringBuilder

import java.util.Scanner;

// Class of ReverseString
public class ReverseString {
    public static void main(String[] args) {
        System.out.println("Enter string to reverse: ");

        Scanner read = new Scanner(System.in);
        String str = read.nextLine();

        StringBuilder sb = new StringBuilder();

        for (int i = str.length() - 1; i >= 0; i--) {
            sb.append(str.charAt(i));
        }

        System.out.println("Reversed string is:");
        System.out.println(sb.toString());
    }
} 

JP25.java

//Using built - in function

import java.util.Scanner;

// Class of ReverseString
public class ReverseString {
    public static void main(String[] args) {
        //Input from the user
        System.out.println("Enter string to reverse:");

        Scanner read = new Scanner(System.in);
        String str = read.nextLine();

        StringBuilder sb = new StringBuilder(str);

        //Output using built - in function
        System.out.println("Reversed string is:");
        System.out.println(sb.reverse().toString());
    }
}

JP26.java

public class string_to_int {
    public static void main(String args[]) {
        String str = "555";
        int i = Integer.parseInt(str);
        System.out.println(i);

        //Differentiate string and int data type

        System.out.println(str + 100);
        System.out.println(i + 100);
    }
}

JP27.java

public class string_to_int {
    public static void main(String args[]) {
        String str = "200";
        int i = Integer.valueOf(str);
        System.out.println(i);
    }
}  

JP28.java

public class string_to_int {
    public static void main(String args[]) {
        String str = "200AB";
        int i = Integer.valueOf(str);
        System.out.println(i);
    }
}       

JP29.java

public class string_to_int {
    public static void main(String args[]) {
        String str1 = "200AB";
        String str2 = "200";
        try {
            int i = Integer.valueOf(str1);
            System.out.println(i);
        } catch (NumberFormatException e) {
            System.out.println("The String cannot be converted to int.");
        }
        try {
            System.out.println(Integer.parseInt(str2));
        } catch (NumberFormatException e) {
            System.out.println("The String cannot be converted to int.");
        }
    }
} 

JP30.java

public class concatenate_array {
    public static void main(String args[]) {
        int array1[] = {1, 2, 3};
        int array2[] = {4, 5, 6};
        int concatenated_array[] = new int[array1.length + array2.length];
        int counter = 0;
        for (int i = 0; i < array1.length; i++) {
            concatenated_array[i] = array1[i];
            counter++;
        }
        for (int j = 0; j < array2.length; j++) {
            concatenated_array[counter++] = array2[j];
        }
        for (int i = 0; i < concatenated_array.length; i++) {
            System.out.print(concatenated_array[i] + " ");
        }
    }
}

JP31.java

import java.util.Arrays;

public class concatenate_array {
    public static void main(String args[]) {
        int array1[] = {1, 2, 3};
        int array2[] = {4, 5, 6};

        int concatenated_array[] = new int[array1.length + array2.length];
        System.arraycopy(array1, 0, concatenated_array, 0, array1.length);
        System.arraycopy(array2, 0, concatenated_array, array1.length, array2.length);

        System.out.print(Arrays.toString(concatenated_array));
    }
} 

JP32.java

System.arraycopy(array1, 0, concatenated_array, 0, array1.length);

JP33.java

System.arraycopy(array2, 0, concatenated_array, array1.length, array2.length);  

JP34.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        char ch1 = str.charAt(0); //returns the 1st character of the string
        char ch2 = str.charAt(9); //returns the 10th character of the string

        System.out.println("First Character of the String: " + ch1);
        System.out.println("Tenth Character of the String: " + ch2);
    }
}

JP35.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        char ch1 = str.charAt(-1);

        System.out.println(ch1);
    }
}

JP36.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        int res = str.codePointAt(1);

        System.out.println(res);
    }
}

JP37.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        int res = str.codePointAt(-1);

        System.out.println(res);
    }
}

JP38.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        int res = str.codePointBefore(1);

        System.out.println(res);
    }
}

JP39.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        int res = str.codePointBefore(-1);

        System.out.println(res);
    }
}

JP40.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        int res = str.codePointCount(1, 6);

        System.out.println(res);
    }
}

JP41.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";
        int res = str.codePointCount(1, 20);

        System.out.println(res);
    }
}

JP42.java

public class string_methods {
    public static void main(String[] args) {
        String str1 = "LearningJournal";
        String str2 = "Learningjournal";
        String str3 = "LearningJournal";

        System.out.println(str1.compareTo(str2));
        System.out.println(str1.compareTo(str3));
    }
}

JP43.java

public class string_methods {
    public static void main(String[] args) {
        String str1 = "LearningJournal";
        String str2 = "Learningjournal";
        String str3 = "LearningJournal";

        System.out.println(str1.compareToIgnoreCase(str2));
        System.out.println(str1.compareTo(str3));
    }
}

JP44.java

public class string_methods {
    public static void main(String[] args) {
        String str = "Learning";

        System.out.println(str.concat("Journal"));

    }
}

JP45.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.contains("Learn"));
        System.out.println(str.contains("Learner"));

    }
}

JP46.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.contentEquals("Learning"));
        System.out.println(str.contentEquals("LearningJournal"));
        System.out.println(str.contentEquals("Journal"));

    }
}

JP47.java

public class string_methods {
    public static void main(String[] args) {
        char cs[] = {'L', 'e', 'a', 'r', 'n', 'i', 'n', 'g'};
        String str = "";

        System.out.println(str.copyValueOf(cs, 0, 5));
        System.out.println(str.copyValueOf(cs));

    }
}

JP48.java

public class string_methods {
    public static void main(String[] args) {
        char cs[] = {'L', 'e', 'a', 'r', 'n', 'i', 'n', 'g'};
        String str = "";

        System.out.println(str.copyValueOf(cs, 0, 10));

    }
}

JP49.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.endsWith("l"));
        System.out.println(str.endsWith("Journal"));
        System.out.println(str.endsWith("Journ"));

    }
}

JP50.java

public class string_methods {
    public static void main(String[] args) {
        String str1 = "LearningJournal";
        String str2 = "Learningjournal";
        String str3 = "LearningJournal";

        System.out.println(str1.equals(str2));
        System.out.println(str1.equals(str3));

    }
}

JP51.java

public class string_methods {
    public static void main(String[] args) {
        String str1 = "LearningJournal";
        String str2 = "Learningjournal";
        String str3 = "LearningJournal";

        System.out.println(str1.equalsIgnoreCase(str2));
        System.out.println(str1.equalsIgnoreCase(str3));

    }
}

JP52.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal is a MOOC Portal";

        System.out.println(str.indexOf("a"));
        System.out.println(str.indexOf("a", 5));
        System.out.println(str.indexOf("is"));
        System.out.println(str.indexOf("z"));

    }
}

JP53.java

public class string_methods {
    public static void main(String[] args) {
        String str1 = "LearningJournal";
        String str2 = "";

        System.out.println(str1.length());
        System.out.println(str2.length());

    }
}

JP54.java

public class string_methods {
    public static void main(String[] args) {
        String str1 = "LearningJournal";
        String str2 = "";

        System.out.println(str1.isEmpty());
        System.out.println(str2.isEmpty());

    }
}

JP55.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal is a MOOC Portal";

        System.out.println(str.lastIndexOf("a"));
        System.out.println(str.lastIndexOf("a", 5));
        System.out.println(str.lastIndexOf("is"));
        System.out.println(str.lastIndexOf("z"));

    }
}

JP56.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.replace("n", "o"));


    }
}

JP57.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.replaceFirst("n", "o"));


    }
}

JP58.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.startsWith("L"));
        System.out.println(str.startsWith("M"));

    }
}

JP59.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.endsWith("l"));
        System.out.println(str.endsWith("L"));

    }
}

JP60.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.substring(8));
        System.out.println(str.substring(0));
        System.out.println(str.substring(0, 7));

    }
}

JP61.java

public class string_methods {
    public static void main(String[] args) {
        String str = "LearningJournal";

        System.out.println(str.toLowerCase());
        System.out.println(str.toUpperCase());

    }
}

JP62.java

public class Hello {

    //Method created
    public static void newMethod() {
        System.out.println("Hello there!!");
    }

    public static void main(String[] args) {
        newMethod(); //Method called
    }

}

JP63.java

public class method_overloading {
    public static void main(String[] args) {
        method_overloading m = new method_overloading();
        System.out.println(m.add(2, 3));
        System.out.println(m.add(2.5, 3.2));
        System.out.println(m.add(2, 3, 4));
    }
    
    //Two parameters of int type
    public int add(int a, int b) {
        return a + b;
    }

    //Two parameters of double type
    public double add(double x, double y) {
        return x + y;
    }
    
    //Three parameters of int type
    public int add(int p, int q, int r) {
        return p + q + r;
    }
}

JP64.java

public class Parent {
    void display() {
        System.out.println("Hey! I`m your parent.");
    }
}

class Child extends Parent{
    void display() {
        System.out.println("Hi! I`m your child.");
    }

    public static void main(String args[]) {
        Parent obj1 = new Parent();
        obj1.display();

        Child obj2 = new Child();
        obj2.display();
    }
}

JP65.java

public class Parent {
    private void display() {
        System.out.println("Hey! I`m your parent.");
    }
}

class Child extends Parent{
    protected void display() {
        System.out.println("Hi! I`m your child.");
    }

    public static void main(String args[]) {
        Parent obj1 = new Parent();
        obj1.display();

        Child obj2 = new Child();
        obj2.display();
    }
}

JP66.java

public class Parent {
    protected void display() {
        System.out.println("Hey! I`m your parent.");
    }
}

class Child extends Parent{
    protected void display() {
        System.out.println("Hi! I`m your child.");
    }

    public static void main(String args[]) {
        Parent obj1 = new Parent();
        obj1.display();

        Child obj2 = new Child();
        obj2.display();
    }
}

JP67.java

public class Parent {
    public void display() {
        System.out.println("Hey! I`m your parent.");
    }
}

class Child extends Parent{
    public void display() {
        super.display();
        System.out.println("Hi! I`m your child.");
    }

    public static void main(String args[]) {
        Parent obj1 = new Parent();
        obj1.display();

        Child obj2 = new Child();
        obj2.display();
    }
}

JP68.java

public class scope_and_lifetime {
    int num1, num2;   //Instance Variables
    static int result;  //Class Variable
    int add(int a, int b){  //Local Variables
        num1 = a;
        num2 = b;
        return a+b;
    }
    public static void main(String args[]){
        scope_and_lifetime ob = new scope_and_lifetime();
        result = ob.add(10, 20);
        System.out.println("Sum = " + result);
    }
}

JP69.java

public class scope_and_lifetime {
    int num1, num2;   //Instance Variables
    int result; 
    int add(int a, int b){  //Local Variables
        num1 = a;
        num2 = b;
        return a+b;
    }
    public static void main(String args[]){
        scope_and_lifetime ob = new scope_and_lifetime();
        result = ob.add(10, 20);
        num1 = 10;
        System.out.println("Sum = " + result);
    }
}

JP70.java

public class scope_and_lifetime {
    public static void main(String args[]){
        int a = 10;
        //Outer Block
        {
            //Inner Block
            int x = a;
            {
                int y = x;
            }
        }
        System.out.println(y);
    }
}

JP71.java

import java.util.ArrayList;

public class array_vs_arraylist {
    public static void main(String args[]) {
        //Array
        int arr[] = new int[5]; //Creating Array
        //Adding elements to Array
        arr[0] = 1;
        arr[1] = 2;
        arr[2] = 3;
        arr[3] = 4;
        arr[4] = 5;

        //ArrayList
        ArrayList<Integer> arrL = new ArrayList<Integer>(5); //Creating ArrayList
        //Adding elements to ArrayList
        arrL.add(1);
        arrL.add(2);
        arrL.add(3);
        arrL.add(4);
        arrL.add(5);

        //Accessing elements of Array and ArrayList
        System.out.println(arr[2]);
        System.out.println(arrL.get(2));
    }
}

JP72.java

import java.util.ArrayList;

public class array_vs_arraylist {
    public static void main(String args[]) {
        //Array
        int arr[] = new int[5]; //Creating Array
        //Adding elements to Array
        arr[0] = 1;
        arr[1] = 2;
        arr[2] = 3;
        arr[3] = 4;
        arr[4] = 5;

        //ArrayList
        ArrayList<int> arrL = new ArrayList<int>(5); //Creating ArrayList
        //Adding elements to ArrayList
        arrL.add(1);
        arrL.add(2);
        arrL.add(3);
        arrL.add(4);
        arrL.add(5);

        //Accessing elements of Array and ArrayList
        System.out.println(arr[2]);
        System.out.println(arrL.get(2));
    }
}

JP73.java

import java.util.ArrayList;

public class array_vs_arraylist {
    public static void main(String args[]) {
        //ArrayList
        ArrayList<Integer> arrL = new ArrayList<Integer>(5); //Creating ArrayList
        //Adding elements to ArrayList
        arrL.add(1);
        arrL.add(2);
        arrL.add(3);
        arrL.add(4);
        arrL.add(5);
        arrL.add(6);
        arrL.add(7);
        arrL.add(8);

        //Accessing elements of ArrayList
        System.out.println(arrL);
    }
}

JP74.java

import java.util.ArrayList;

public class array_vs_arraylist {
    public static void main(String args[]) {
        //Array
        int arr[] = new int[5]; //Creating Array
        //Adding elements to Array
        arr[0] = 1;
        arr[1] = 2;
        arr[2] = 3;
        arr[3] = 4;
        arr[4] = 5;

        //ArrayList
        ArrayList<Integer> arrL = new ArrayList<Integer>(5); //Creating ArrayList
        //Adding elements to ArrayList
        arrL.add(1);
        arrL.add(2);
        arrL.add(3);
        arrL.add(4);
        arrL.add(5);

        //Accessing elements of Array and ArrayList
        System.out.println(arr.length);
        System.out.println(arrL.size());
    }
}

JP75.java

import java.util.Arrays;

public class array_without_loops {
    public static void main(String args[]) {
        int arr[] = {1, 2, 3, 4, 5};

        String str = Arrays.toString(arr);
        System.out.println(str);
    }
}

JP76.java

import java.util.Arrays;

public class array_without_loops {
    public static void main(String args[]) {
        int arr[][] = {{1}, {1, 2}, {1, 2, 3}};

        String str = Arrays.deepToString(arr);
        System.out.println(str);
    }
}

JP77.java

import java.util.Arrays;

public class array_without_loops {
    public static void main(String args[]) {
        int arr[][] = {{1}, {1, 2}, {1, 2, 3}};

        String str = Arrays.toString(arr);
        System.out.println(str);
    }
}

JP78.java

import java.util.ArrayList;
import java.util.List;


public class streams_in_java {

    public static void main(String[] args) {

        //Creating a List
        List<Integer> list = new ArrayList();
        
        //Adding elements to the list
        list.add(5);
        list.add(2);
        list.add(9);
        list.add(11);
        list.add(16);

        int sum = 0;
        for (int i : list) {
            if (i > 10) {
                sum = sum + i;
            }
        }

        //Displaying the sum of elements greater than 10.
        System.out.println(sum);
    }

}

JP79.java

import java.util.ArrayList;
import java.util.List;


public class streams_in_java {

    public static void main(String[] args) {

        //Creating a List.
        List<Integer> list = new ArrayList();

        //Adding elements to the list.
        list.add(5);
        list.add(2);
        list.add(9);
        list.add(11);
        list.add(16);

        /*Using Java Streams to find out
          the sum of elements greater than 10*/
        int sum = list.stream().filter(i -> i > 10).mapToInt(i -> i).sum();
        
        System.out.println(sum);
    }

}

JP80.java

public static void main(String args[]) {

    String[] arr = new String[]{"a", "b", "c"};
    Stream<String> stream = Arrays.stream(arr);
    stream = Stream.of("a", "b", "c");
    
}

JP81.java

import java.util.*;
import java.util.stream.*;

public class streams_in_java {
    public static void main(String args[]) {

        // Creating a List.
        List<Integer> number = Arrays.asList(2, 3, 4, 5);

        // Map Method.
        List<Integer> square = number.stream().map(x -> x * x * x).
                collect(Collectors.toList());
        System.out.println("Squares: " + square);

        // Creating a List of Strings.
        List<String> names =
                Arrays.asList("Amazon", "Google", "Apple", "Microsoft");

        // Filter Method.
        List<String> result = names.stream().filter(s -> s.startsWith("A")).
                collect(Collectors.toList());
        System.out.println("Strings with first letter 'A': " + result);

        // Sorted Method.
        List<String> show =
                names.stream().sorted().collect(Collectors.toList());
        System.out.println("String in Alphabetical Order: " + show);

    }
}