Runtim Exception extends Exception and Custom Exception extends from Exception Why the later one is compile time exception and other is not?

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In Java I have a Exception class that extends from Exception, But whenever I throw it, the compiler says that it needs to be caught/ must declare that methods throws Exception.

When I use a RuntimeException that extends from Exception, the compiler does not stop, It takes them as Runtime Exception and we need not handle it.

Is there a way where I can make a MyException extend from Exception and still have it as runtime exception.? or What makes this as possibility in class RuntimeException

private void compileTime() throws MyException{
        throw new MyException();
    }

    private void runTime() {
        throw new MyRuntimeException();
    }

    class MyException extends Exception {

    }
    class MyRuntimeException extends RuntimeException {

    }

RuntimeException are a subset of unchecked exceptions for exceptions from which recovery is possible.

unchecked exceptions are not checked at compile-time which means that the compiler doesn't require methods to catch or to specify (with a throws) them.

The unchecked exceptions classes are the class RuntimeException and its subclasses, and the class Error and its subclasses. All other exception classes are checked exception classes.

Please check the Exception Hierarchy through this image :

In short, Any exception that derives from "Exception" is a checked exception, whereas a class that derives from RuntimeException is un-checked. RuntimeExceptions do not need to be explicitly handled by the calling code.

Extending Exception/RunTimeException in java?, What is the difference between extending exception and runtime exception? Implementing a Custom Exception. Creating a custom checked exception is simple. You already saw multiple parts of it when I explained the 4 best practices for implementing custom exceptions. When you implement a checked exception, you need to extend the class Exception. That’s the only thing you need to do to create a custom exception class.

No way. According to specifications, only exceptions extended from RuntimeException class or Error class are considered as unchecked exceptions (JLS 7, p. 11.1.1).

RuntimeException (Java Platform SE 7 ), . For example, if you have declared an array of size 5 in your program, and trying to call the 6th element of the array then an ArrayIndexOutOfBoundsExceptionexception occurs. 5 Runtim Exception extends Exception and Custom Exception extends from Exception Why the later one is compile time exception and other is not? Jan 21 '13 4 Can cassandra be installed in Local host?

What you are calling a "compile-time" exception is known as a Checked exception. As you say the compiler will require you to include it in your method signature and your callers will need to handle the possibility that it may be thrown.

RuntimeException is explicitly intended for the "unchecked" exception case.

From the docs

A method is not required to declare in its throws clause any subclasses of RuntimeException that might be thrown during the execution of the method but not caught.

So just extend RuntimeException if you want an unchecked excption.

Checked vs Unchecked exceptions in Java, RuntimeException are a subset of unchecked exceptions for exceptions from which recovery is possible. unchecked exceptions are not checked at compile-time which means that the compiler doesn't require methods to catch or to specify (with a throws) them. If you extend RuntimeException or one of its subclasses, your exception will be treated as a runtime exception (it will not be checked). When a situation arises for which you would want to throw the exception, use the throw keyword with a new object from your exception class, for example: Syntax Throwing an Exception

RuntimeException doesn't need the try-catch combo or throws in the beginning of method. Simply because it happens in runtime such as you want to refer the 14th element of a 10 element long array or get a NullPointerException because you forgot to set value of something, these cases cannot be predicted since the program would work well with the right structures. Also as others say, this is un-checked.

Exception is different, you have to tell the program what to do with the well known exception cases. That means the complier will force you to handle the exception somehow before it starts to run.

java, Learn 4 best practices for custom exceptions in Java. You should provide detailed information about the situation that caused the exception, and you should not remove As soon as one of your client-facing methods throws an exception, public class MyBusinessException extends Exception { public  There are two types of exceptions: checked exception and unchecked exception. In this guide, we will discuss them. The main difference between checked and unchecked exception is that the checked exceptions are checked at compile-time while unchecked exceptions are checked at runtime. Checked exceptions are checked at compile-time.

Implement Custom Exceptions in Java: Why, When and How, Any Exception that can be thrown by a method is part of the method's public Thus, the compiler does not require that you catch or specify runtime exceptions One case where it is common practice to throw a RuntimeException is when the Generally speaking, do not throw a RuntimeException or create a subclass of  That's is an interesting approach, but not the one we are using. We have 2 base exception classes, one that extends RuntimeException and one that extends Exception. Both base classes are identical in every other respect. Both are mimicking the JDK 1.4's built in exception chaining in our JDK1.3 code. Here's a code snippet

Unchecked Exceptions, public class RuntimeException extends Exception Unchecked exceptions do not need to be declared in a method or Since: JDK1.0; See Also: Serialized Form; See The Java™ Language Specification : 11.2 Compile-Time Checking of Exceptions The detail message is saved for later retrieval by the Throwable. Java provides two different options to handle an exception. You can either use the try-catch-finally approach to handle all kinds of exceptions. Or you can use the try-with-resource approach which allows an easier cleanup process for resources. Try-Catch-Finally. That is the classical approach to handle an exception in Java. It can consist of 3

Java Checked vs Unchecked Exceptions, Learn the difference between checked vs unchecked exceptions in Java, with If an exception is not handled in the application, then it will propagate to JVM and JVM you will get compile time error with message – Unhandled exception type “The strange thing is that RuntimeException is itself subclass of Exception i.e.  Note that Java Exception handling is a framework that is used to handle runtime errors only, compile time errors are not handled by exception handling in java. We use specific keywords in java program to create an exception handler block, we will look into these keywords next. Java Exception Handling Keywords

Comments
  • The question is how it does it internally?
  • +1 All other Throwable subclasses, even direct sub-classes of Throwable are checked. (i.e. it might not be an Exception or an Error)