Exception in thread "main" java.lang.ArithmeticException: / by zero

java exception main arithmeticexception
Akira Noguchi picture Akira Noguchi · May 30, 2012 · Viewed 47.4k times · Source

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?

Answer

wattostudios picture wattostudios · May 30, 2012

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.

Related questions

How do you assert that a certain exception is thrown in JUnit 4 tests?

How can I use JUnit4 idiomatically to test that some code throws an exception? While I can certainly do something like this: @Test public void testFooThrowsIndexOutOfBoundsException() { boolean thrown = false; try { foo.doStuff(); } catch (IndexOutOfBoundsException e) { thrown = true; } assertTrue(thrown); } I …

Read More
How to solve java.lang.NoClassDefFoundError?

I've tried both the example in Oracle's Java Tutorials. They both compile fine, but at run-time, both come up with this error: Exception in thread "main" java.lang.NoClassDefFoundError: graphics/shapes/Square at Main.main(Main.java:7) Caused by: java.…

Read More
What could cause java.lang.reflect.InvocationTargetException?

Well, I've tried to understand and read what could cause it but I just can't get it: I have this somewhere in my code: try{ .. m.invoke(testObject); .. } catch(AssertionError e){ ... } catch(Exception e){ .. } Thing is that, when it tries …

Read More