Aggregate runtime exceptions in Java 8 streams -

let's have method throws runtime exception. i'm using stream call method on items in list.

class abc {      public void dostuff(myobject myobj) {         if (...) {             throw new illegalstateexception("fire! fear! foes! awake!");         }         // stuff...     }      public void dostuffonlist(list<myobject> myobjs) {         try {             myobjs.stream().foreach(abc:dostuff);         } catch(aggregateruntimeexception??? are) {             ...         }                  } } 

now want items in list processed, , runtime exceptions on individual items collected "aggregate" runtime exception thrown @ end.

in real code, making 3rd party api calls may throw runtime exceptions. want make sure items processed , errors reported @ end.

i can think of few ways hack out, such map() function catches , returns exception (..shudder..). there native way this? if not, there way implement cleanly?

in simple case dostuff method void , care exceptions, can keep things simple:

myobjs.stream()     .flatmap(o -> {         try {             abc.dostuff(o);             return null;         } catch (runtimeexception ex) {             return stream.of(ex);         }     })     // stream of thrown exceptions.     // can collect them list or reduce 1 exception     .reduce((ex1, ex2) -> {         ex1.addsuppressed(ex2);         return ex1;     }).ifpresent(ex -> {         throw ex;     }); 

however, if requirements more complicated , prefer stick standard library, completablefuture can serve represent "either success or failure" (albeit warts):

public static void dostuffonlist(list<myobject> myobjs) {     myobjs.stream()             .flatmap(o -> completedfuture(o)                     .thenaccept(abc::dostuff)                     .handle((x, ex) -> ex != null ? stream.of(ex) : null)                     .join()             ).reduce((ex1, ex2) -> {                 ex1.addsuppressed(ex2);                 return ex1;             }).ifpresent(ex -> {                 throw new runtimeexception(ex);             }); }