Create 28_Exception handling

This commit consists of:
1]try-catch statements
2]Specific exception
3]Nested try-catch
4]Exception class
5]throw-throws keywords
6]finally keyword

Author: PratikMore55

28_Exception handling

@@ -0,0 +1,204 @@
+package com.company;
+
+
+public class try_catch {
+    public static void main(String[] args) {
+        int a = 3000;
+        int b = 0;
+        try{
+            int c = a/b;
+            System.out.println("The result is:" +c);
+        }
+        catch (Exception e){
+            System.out.println("We failed to divide. Reason: ");
+            System.out.println(e);
+            System.out.println("End of the program");
+        }
+    }
+}
+
+// Specific exceptions
+
+package com.company;
+
+import java.util.Scanner;
+
+public class Specific_exceptions {
+    public static void main(String[] args) {
+        int[] marks = new int[3];
+        marks[0]=30;
+        marks[1]=38;
+        marks[2]=49;
+        Scanner sc = new Scanner(System.in);
+        System.out.println("Enter the array index: ");
+        int ind = sc.nextInt();
+
+        System.out.println("Enter the number you want to dic=vide with: ");
+        int number = sc.nextInt();
+        try{
+            System.out.println("The value at array index entered is: " +marks[ind]);
+            System.out.println("The value of array-value/number is: "+marks[ind]/number);
+        }
+        catch (ArithmeticException e){
+            System.out.println("Some exception occured!");
+            System.out.println(e);
+        }
+        catch (ArrayIndexOutOfBoundsException e){
+            System.out.println("Some exception occured!");
+            System.out.println(e);
+        }
+        catch (Exception e){
+            System.out.println("Some other exception occured!");
+            System.out.println(e);
+        }
+    }
+}
+
+
+//Nested try-catch
+
+package com.company;
+
+import java.util.Scanner;
+
+public class Nested_try_catch {
+    public static void main(String[] args) {
+        int[] marks = new int[3];
+        marks[0]=30;
+        marks[1]=38;
+        marks[2]=49;
+        Scanner sc = new Scanner(System.in);
+        boolean flag = true;
+        while (flag) {
+
+            System.out.println("Enter the array index: ");
+            int ind = sc.nextInt();
+            try {
+                System.out.println("Welcome to this world");
+                try {
+                    System.out.println(marks[ind]);
+                    flag = false;
+                } catch (ArrayIndexOutOfBoundsException e) {
+                    System.out.println("Sorry this index does not exist!");
+                    System.out.println("Exception in level 2");
+//                    flag = false;
+                }
+            } catch (Exception e) {
+                System.out.println("Exception in level 1");
+            }
+        }
+    }
+}
+
+
+//Exception class
+
+package com.company;
+
+import java.util.Scanner;
+
+class MyException extends Exception{
+    @Override
+    public String toString(){
+        return super.toString();
+        }
+
+    @Override
+    public String getMessage() {
+        return super.getMessage();
+    }
+}
+public class Exception_class {
+    public static void main(String[] args) {
+        int a;
+        Scanner sc = new Scanner(System.in);
+        a=sc.nextInt();
+        if (a<9){
+            try {
+                throw new  MyException();
+            }
+            catch(Exception e){
+                System.out.println(e.getMessage());
+                System.out.println(e.toString());
+                e.printStackTrace();
+            }
+        }
+    }
+}
+
+
+//throw-throws kwywords
+
+package com.company;
+
+class NegativeRadiusException extends Exception{
+    @Override
+    public String toString() {
+        return "Radius cannot be negative";
+    }
+
+    @Override
+    public String getMessage() {
+        return "Radius cannot be negative";
+    }
+}
+public class Throw_throws {
+    public static double area(int r) throws NegativeRadiusException{
+        if (r<0){
+            throw new NegativeRadiusException();
+        }
+        double result = Math.PI*r*r;
+        return result;
+    }
+    public static int divide(int a, int b) throws ArithmeticException{
+        int result = a/b;
+        return result;
+    }
+    public static void main(String[] args) {
+        try {
+//            int c = divide(3,3);
+//            System.out.println(c);
+            double ar = area(0);
+            System.out.println(ar);
+        }
+        catch (Exception e){
+            System.out.println("Exception");
+        }
+//        double ar = area(5);
+    }
+}
+
+
+// finally keyword
+
+package com.company;
+
+public class Finally {
+    public static int greet() {
+        try {
+            int a = 60;
+            int b = 4;
+            int c = a / b;
+            return c;
+        } catch (Exception e) {
+            System.out.println(e);
+        } finally {
+            System.out.println("This is the end of this function");
+        }
+        return 0;
+    }
+    public static void main(String[] args) {
+//        try {
+//            int a = 5;
+//            int b = 0;
+//            int c = a/b;
+//        }
+//        catch (Exception e){
+//            System.out.println(e);
+//        }
+//        finally {
+//            System.out.println("This is the end of this program");
+            int k = greet();
+        System.out.println(k);
+        }
+    }