Exception in thread "main" java.lang.ArithmeticException: / by zero
arithmeticexception, exception, java, program-entry-point
Solution
`java.lang.ArithmeticException` is a type of `Exception` that aims to better describe what the problem actually is. There's no point just creating an `Exception`, as it really could be caused by anything. By generating an `ArithmeticException`, the user can immediately know that the problem is something to do with a calculation. An `Exception` can be thrown by any piece of code, including in calculations such as your example.
`Exception in thread "main"` means that the exception is thrown by the `main()` method, which also happens to be the primary Thread that is running your code.
Problem
I have two questions about `Exceptions`. Firstly, I got this message from my code... ``` Exception in thread "main" java.lang.ArithmeticException: / by zero ``` This error message means dividing by zero, such as by doing `int a = 5 / 0;` A method can throw an `Exception` class instance, can't it? But this is an expression. Why can an expression throw an `Exception` class instance ? My second question is about `thread "main"`. What is `thread "main"`? Does `"main"` mean the `static main` method?