unchecked exception

NullPointerExceptionのようなRuntimeException系のexceptionは
uncheckedExceptionで、try,catch不要

public class Outer {
    public static void main(String[] args) {
            NullPointerException npe = new NullPointerException();
            System.out.println(npe instanceof RuntimeException);
            String[] str = null;
            String s = str[0];
    }
}

Exception in thread "main" true
java.lang.NullPointerException
	at com.mycompany.mavenproject1.Outer.main(Outer.java:13)

InterruptedExceptionは、RuntimeExceptionではない。

    public static void main(String[] args) {
            Exception ie = new InterruptedException();
            System.out.println(ie instanceof RuntimeException);
            //Thread.sleep(1000);
    }

false

try,catchなしのため、compile error

public class Outer {
    public static void main(String[] args) {
            Exception ie = new InterruptedException();
            System.out.println(ie instanceof RuntimeException);
            Thread.sleep(1000);
    }
}

Exception in thread "main" java.lang.RuntimeException: Uncompilable code - 例外java.lang.InterruptedExceptionは報告されません。スローするには、捕捉または宣言する必要があります
	at com.mycompany.mavenproject1.Outer.main(Outer.java:1)
Command execution failed.