Java Exception Handling : FAQ Exception Handling

Java Exception Handling

What is the difference between error and an exception?

An error is an irrecoverable condition occurring at run time. Such as OutOfMemory error. Exceptions are conditions that occur because of bad input etc. e.g. FileNotFoundException will be thrown if the specified file does not exist.

What is an Java Exception Handling?

An exception is a problem that arises during the execution of a program. Exceptions are caught by handlers positioned along the thread’s method invocation stack.

What do you mean by Checked Exceptions in Java Exception Handling?

It is an exception that is typically a user error or a problem that cannot be foreseen by the programmer. For example, if a file is to be opened, but the file cannot be found, an exception occurs. These exceptions cannot simply be ignored at the time of compilation.

Explain Runtime Exceptions?

It is an exception that occurs that probably could have been avoided by the programmer. As opposed to checked exceptions, run time exceptions are ignored at the time of compilation.

Which are the two subclasses under Exception class?

The Exception class has two main subclasses : IOException class and RuntimeException Class.

When throws keyword is used?

If a method does not handle a checked exception, the method must declare it using the throws keyword. The throws keyword appears at the end of a method’s signature.

When throw keyword is used?

An exception can be thrown, either a newly instantiated one or an exception that you just caught, by using throw keyword.

How finally used under Exception Handling?

The finally keyword is used to create a block of code that follows a try block. A finally block of code always executes, whether or not an exception has occurred.

What things should be kept in mind while creating your own exceptions in Java?

While creating your own exception: All exceptions must be a child of Throwable. If you want to write a checked exception that is automatically enforced by the Handle or Declare Rule, you need to extend the Exception class. You want to write a runtime exception, you need to extend the RuntimeException class.

Difference between throw and throws?

It includes: Throw is used to trigger an exception where as throws is used in declaration of exception. Without throws, Checked exception cannot be handled where as checked exception can be propagated with throws.

When ArithmeticException is thrown?

The ArithmeticException is thrown when integer is divided by zero or taking the remainder of a number by zero. It is never thrown in floating-point operations.

When is the ArrayStoreException thrown?

When copying elements between different arrays, if the source or destination arguments are not arrays or their types are not compatible, an ArrayStoreException will be thrown.

Adarsh Patel

My Self Adarsh Suryakant Patel. Currently I am working as Assistant Professor at Parul Instiute of Engineering and Technology, MCA Department, Limda, Vadodara. Major Responsibility : * Lectures * Organizing Training and Expert Sessions for * Placement and Recruitment * Faculty Representative