JavaPractice

this exercice is for parctise in exception

exercice 1 :

Create a program that prompts the user to enter an integer. If the user enters a non-integer value, catch the exception and display an appropriate error message. Keep prompting the user until a valid integer is entered. For example, if the user enters ”abc” instead of an integer, the program should display an error message like ”Invalid input. Please enter a valid integer.” and prompt the user again.

exercice 2 :

Write a program that reads a file named ”input.txt” and counts the number of lines in the file. If the file doesn’t exist, catch the exception and display an error message. If the file exists but is empty, display a message indicating that the file is empty. Consider the following scenarios:

• If the file ”input.txt” does not exist in the current directory, the program should display an error message like ”File not found: input.txt”.
• If the file ”input.txt” exists but is empty, the program should display a message like ”The file is empty.”
• If the file ”input.txt” exists and contains lines of text, the program should display the number of lines in the file, for example, ”Number of lines in the f ile: 10”

exercice 3 :

Implement a custom exception called ”InvalidMatrixException”. Create a method that takes a 2D integer array as input and throws an InvalidMatrixException if the array is not a square matrix (i.e., the number of rows and columns are not equal). The method should return the sum of all elements in the matrix if it is a valid square matrix. In the main method, prompt the user to enter the number of rows and columns for a matrix. Create a 2D integer array of the specified size and fill it with user input values. Use the custom method to calculate the sum of the matrix elements and display the result. Handle the InvalidMatrixException and display an appro priate error message telling the user how many rows they should add/remove of the matrix in order to be square.