Exception: The exception refers to an exceptional event. Exception is an event that disrupts the normal flow of the program, during program execution. Exception object: When an error occurs within a method, the method creates an object and hands it to the runtime system. This object is known as an exception object. It contains the … Read more
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Marker/Tagging Interfaces: An interface with no methods is known as a marker or tagged interface. Why marker interface used: It provides some useful information to the JVM/compiler so that the JVM/compiler performs some special operations on it. It is used for better readability of code. Example: Serializable, Cloneable, etc. Syntax public interface Interface_Name … Read more
1. getMessage(): returns the message string about the exception. Syntax: public String getMessage() 2. getCause(): returns the cause of the exception. It will return null if the cause is unknown or non-existent. Syntax: public Throwable getCause() 3. toString(): returns a short description of the exception. Description of the exception = class name + “: “ + message. … Read more
Custom exception: You can define your own exception also. These exceptions are known as custom exceptions. Note: 1. For writing custom-checked exceptions, extend the Exception class. 2. For writing custom unchecked exceptions, extend the RuntimeException class. Java Custom Exception Example class MyException extends Exception { public MyException(String message) { super(message); } } class … Read more
If the superclass method does not declare an exception then the subclass overridden method cannot declare the checked exception but it can declare an unchecked exception. If the superclass method declares an exception then the subclass overridden method can declare the same exception, subclass exception, or no exception but cannot declare the parent exception of … Read more
Exception propagation is a way of propagating exceptions from method to method. Let an exception occur in a method at the top of the call stack and if it is not caught then it propagates to the previous method in the call stack, if it is not caught here then it again propagates to the … Read more
throws are used to throw an exception object implicitly. It is used with the method signature. More than one type of exception can be declared with method signature, they should be comma-separated. Note: throws are mainly used to throw a checked exception. If you are calling a method that declares an exception, you must either … Read more
throw is used to throw an exception object explicitly. It can take only one argument and that will be an exception object. Exception object to be thrown can be of either checked or unchecked exception type. Syntax throw exception_object; Java throw keyword Example class ArithmaticTest{ public void division(int num1, int num2){ try{ //java.lang.ArithmeticException … Read more
The finally block is mainly used to do clean-up tasks. It is always executed even when no exceptions occur. It will not execute only in case the program exits using System. exit() or because of some fatal error causes the program to abort. It is followed by either a catch or a try block. Note: … Read more