PrintWriter and PrintStream never throw IOExceptions

I think that since System.out and System.err are instances of PrintStream, some more relaxed error handling was provided. This was probably, as other posters have mentioned, to smooth the way for those transitioning from C/C++ circa 1995. When the Reader/Writer API was added, PrintWriter was created to parallel the existing PrintStream. One application where this … Read more

Active Directory COM Exception – An operations error occurred (0x80072020)

The issue is often that the context for which the Active Directory calls is made is under a user that does not have permissions (also can happen when identity impersonate=”true” in ASP.NET, due to the fact that the users token is a “secondary token” that cannot be used when authenticating against another server from: … Read more

In a Java 7 multicatch block what is the type of the caught exception?

Yes, the type of ex is the most specific supertype of both CharacterCodingException and UnknownServiceException, which would be IOException. Edit: Straight from the horse’s mouth on Informally, the lub (least upper bound) is the most specific supertype of the types in question.

Order of catching exceptions in Java

The order is whatever matches first, gets executed (as the JLS clearly explains). If the first catch matches the exception, it executes, if it doesn’t, the next one is tried and on and on until one is matched or none are. So, when catching exceptions you want to always catch the most specific first and … Read more

Why can’t I throw an exception in a Java 8 lambda expression? [duplicate]

You are not allowed to throw checked exceptions because the accept(T t, U u) method in the java.util.function.BiConsumer<T, U> interface doesn’t declare any exceptions in its throws clause. And, as you know, Map#forEach takes such a type. public interface Map<K, V> { default void forEach(BiConsumer<? super K, ? super V> action) { … } } … Read more