Pasted

final Stream lengths = Arrays.stream(args).map(new Function<String, Integer>() {
  @Override
  public Integer apply(final String t) {
        return check(t);
  };
}); 
 
results in:
 
Exception in thread "main" java.lang.IllegalArgumentException
    at ch.fhnw.claudemartin.SomeClass.check(SomeClass.java:14)
    at ch.fhnw.claudemartin.SomeClass$1.apply(SomeClass.java:33)
    at ch.fhnw.claudemartin.SomeClass$1.apply(SomeClass.java:1)
    at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
    at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
    at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
    at ch.fhnw.claudemartin.SomeClass.main(SomeClass.java:37)
 
------------------------------------------------------------
 
Stream lengths = Arrays.stream(args).map(name -> check(name));
 
results in:
 
Exception in thread "main" java.lang.IllegalArgumentException
    at ch.fhnw.claudemartin.SomeClass.check(SomeClass.java:14)
    at ch.fhnw.claudemartin.SomeClass.lambda$0(SomeClass.java:29)
    at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
    at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
    at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
    at ch.fhnw.claudemartin.SomeClass.main(SomeClass.java:38)