What is an exception in java?

What is an exception in java?

• 1.
  What is anexception in java? handle exception in java Java - exception. An exception (or extraordinary event) is a problem that occurs during the execution of a program. When an exception occurs, the normal flow of the program is interrupted and the program / application terminates abnormally, which is not recommended, therefore, these exceptions have to be controlled. Types of exception to handle exception in java There are Two type of exception  Checked Exception Checked exception occur at compile time or generated by compiler.  Unchecked Exception Unchecked exception occured at run time Type of Exception Checked and unchecked exception type
• 2.
  handle exception injava  ArithmeticException It is thrown when an exceptional condition has occurred in an arithmetic operation. Class: Java.lang.ArithmeticException This is the built-in-class present in the java.lang package. This exception occurs when the integer is divided by zero. Example: Class example 1 { public static void main (String [] args[]) { try{ int num1 = 30, num2 = 0; int output = num1 / num2; System.out.println ("Result:" + output); } Catch (ArithmeticException) { System.out.println ("You should not divide a number by zero"); } } }
• 3.
  Output You should notdivide a number by zero Explanation: In the above example I divided an integer by a zero and because of this an arithmetic exception was thrown.  ArrayIndexOutOfBoundsException It is thrown to indicate that an array has been accessed with an invalid index. The index is either negative or equal to or greater than the size of the array. Class: Java.lang.ArrayIndexOutOfBoundsException This exception occurs when you try to access an array index that does not exist. For example, if the array has only 5 elements and we are trying to display the 7th element it will throw an exception. Example: Class exception demo 2 { public static void main (String [] args[]) { try{ int a [] = new int [10]; Array contains only 10 elements [11] = 4; } Catch (ArrayIndexOutOfBoundsException e) { System.out.println ("ArrayIndexOutofBounds"); } } } Result ArrayIndexOutofBounds  ClassNotFoundException This exception is raised when we try to access a class whose definition is not found Example
• 4.
  Package com.journaldev.exception; Public classDataTest { public static void main (String [] args) { try { Class.forName ("com.journaldev.MyInvisibleClass"); ClassLoader.getSystemClassLoader () loadClass ("com.journaldev.MyInvisibleClass").; ClassLoader.getPlatformClassLoader () loadClass ("com.journaldev.MyInvisibleClass").; } Catch (ClassNotFoundException e) { e.printStackTrace (); } } } Result ClassNotFoundExcepion  FileNotFoundException This exception is raised when a file is unreachable or does not open. Example Import java.io.BufferedReader; Import java.io.File; Import java.io.FileReader;
• 5.
  Import java.io.IOException; Public classFileNotFoundExceptionExample { Private static final string filename = "input.txt"; public static void main (String [] args) { Bufferreader rd = null; try { // Open the file for reading. rd = new BufferedReader (new FileReader (new File (filename))); // Read all the contents of the file. String inputline = null; While ((inputline = rd.readLine ())! = Null) Println (inputLine); } Catch (before IOException) { System.err.println ("An IOException was caught!"); ex.printStackTrace (); } After all // Close the file. try { rd.close (); } Catch (before IOException) { System.err.println ("An IOException was caught!"); ex.printStackTrace (); } } } } OutPut
• 6.
  FileNotFoundException  IOException It isthrown when the input-output operation fails or is interrupted Example Import java.util. *; Public class ScannerIOExceptionExample1 { public static void main (String [] args) { // create a new scanner with the specified string object ScannerScan = new Scanner ("Hello World! Hello My Programming School"); // print the line System.out.println ("" + scan.nextLine ()); // check if there is an IO exception System.out.println ("Exception output:" + scan.ioException ()); scan.close (); } } OutPut: Hello World! Hello My Programming School Exception output: null  InterruptedException It is thrown when a thread is waiting, sleeping, or processing something, and it is interrupted.
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  Example Package com.javaguides.corejava; Class childhread'sextension thread { Public void run () { try { Thread.Sleep (1000); } Catch (interrupted exception) { System.err.println ("InterruptedException caught!"); e.printStackTrace (); } } } Public class InterruptedExceptionExample { Public static void main (String [] args) throws InterruptedException { ChildThread childThread = new ChildThread (); childThread.start (); childThread.interrupt (); } } Out Put: IntrruptedException  NoSuchFieldException It is thrown when a class does not contain a specified field (or variable)
• 8.
   NoSuchMethodException It isthrown when using a method that is not found.  NullPointerException This exception is raised when referring to members of a null object. Null represents nothing Class: Java.lang.NullPointer Exception Whenever a member is called with an "null" object, an object of this class is created. Example Class exception 2 { public static void main (String [] args[]) { try{ String str = null; System.out.println (str.length ()); } Catch (NullPointerException e) { Println ("NullPointerException .."); } } } Result NullPointerException .. Here, there is a length () function, which should be used on an object. However the string object str in the above example is null so it is not the object that caused the NullPointerException.  NumberFormatException This exception is raised when a method cannot convert a string to a numeric format. Class: Java.lang.NumberFormatException This exception occurs when a string is parsed on any numeric variable. For example, the statement int num = Integer.parseInt ("XYZ"); The numbers will throw a FormatException because the string "XYZ" cannot be parsed to int. Example
• 9.
  Class ExceptionDemo3 { public staticvoid main (String [] args[]) { try{ int num = Integer.parseInt ("XYZ"); Println (number); } Catch (numberFormatException e) { System.out.println ("Number format exception occurred"); } } } Result Number format exception occurred  Runtime Exception This represents any exception that occurs during runtime. Example You can see above example of FileNotFoundException  StringIndexOutOfBoundsException It is thrown by string class methods to indicate that the index is either negative by the size of the string Class: Java.lang.StringIndexOutOfBoundsException Whenever an index is not implemented in a string, an object of this class is created, which is not in the range. Each character of a string object is stored in a special index starting at 0. To get a character present in a particular index of a string we can use charAt (int), a method of java.lang.tring. Where the difference is the logic index. Example Class ExceptionDemo4 { public static void main (String [] args[]) { try{ String str = "beginbook";
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  Println (str.length ());; char c = str.charAt (0); c = str.charAt (40); Println (c); } Catch (StringIndexOutOfBoundsException e) { Println ("StringIndexOutOfBoundsException !!"); } } } Result StringIndexOutOfBoundsException !! For more Click HERE Recommended Posts:  Find the area of triangle and rectangle in java  How to compare dates in java|algorithm with source code  Java roll dice 10000 times with algorithm and source code  Write a Java program that displays the number of characters, lines and words in a text  Write a Java program that reads a file and displays the file on the screen with a line number before each line  Write a Java program that reads a file name from the user, then displays information about whether the file exists, readable, writable, type of file and the length of the file in bytes  Java program to make frequency count of vowels, consonants, special symbols, digits, words in a given text  Write a Java program for sorting a given list of names in ascending order  Write a java program to Checks whether a given string is a palindrome or not  Write a java program to perform multiplication of two matrices  write a java program that print the fibonacci series for a give number.  Write a Java Program that find the factorial of a number  Write a Java program that find prime numbers between 1 to n  Write a Java program that prints all real and imaginary solutions to the quadratic equation  Odd and Even number in java | Algorithm  Even number in java | algorithm with source code  find unique elements in array java | algorithm and source code  Write a Java program for sorting a given list of names in ascending order  write a java program that print the fibonacci series for a give number.  Write a Java program that prints all real and imaginary solutions to the quadratic equation  Missing Number in java with example  Java greater number using loop  Java Print function with example | Difference between print () and println () in java  What is the Fibonacci series? in java | Displaying the Fibonacci sequence using a loop
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