I find NullPointerException to be interesting since there are no explicit pointers in Java. Here is a program that throws such an exception.
class c {
public static void main(String[]s) {
throw new NullPointerException();
}
}
What is the shortest Java program that throws NullPointerException?
interface P{static void main(String[]a){throw null;}}
From the documentation:
Class NullPointerException
...
Thrown when an application attempts to use null in a case where an object is required. These include:
...
- Throwing null as if it were a Throwable value.
enum instead of class.
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Interface having default public scopes in Java 8.
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-2 bytes thanks to @PeterTaylor.
class C{public static void main(String[]s){s=null;s.clone();}}
Without knowing about the throw trick, this is the first thing that occurred to me. Using the main class's type is the shortest one available, and casting null is shorter than declaring C c=null;. notify is also the shortest method on an object that doesn't throw an exception.
((C)null).wait(); will work too.
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wait's declaration throws InterruptedException, so the class will not compiler without a try/catch or throws declaration.
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