### Question:
StackHelper { @Nonnull @ReturnsMutableCopy public static <ELEMENTTYPE> NonBlockingStack <ELEMENTTYPE> newStack (@Nonnegative final int nInitialCapacity) { return new NonBlockingStack <> (nInitialCapacity); } private  StackHelper(); @Nonnull @ReturnsMutableCopy static NonBlockingStack <ELEMENTTYPE> newStack(@Nonnegative final int nInitialCapacity); @Nonnull @ReturnsMutableCopy static NonBlockingStack <ELEMENTTYPE> newStack(); @Nonnull @ReturnsMutableCopy static NonBlockingStack <DSTTYPE> newStackMapped(@Nullable final Collection <? extends SRCTYPE> aCollection,
                                                                              @Nonnull final Function <? super SRCTYPE, DSTTYPE> aMapper); @Nonnull @ReturnsMutableCopy static NonBlockingStack <DSTTYPE> newStackMapped(@Nullable final SRCTYPE [] aArray,
                                                                              @Nonnull final Function <? super SRCTYPE, DSTTYPE> aMapper); @Nonnull @ReturnsMutableCopy static NonBlockingStack <ELEMENTTYPE> newStack(@Nullable final ELEMENTTYPE aValue); @Nonnull @ReturnsMutableCopy @SafeVarargs static NonBlockingStack <ELEMENTTYPE> newStack(@Nullable final ELEMENTTYPE... aValues); @Nonnull @ReturnsMutableCopy static NonBlockingStack <ELEMENTTYPE> newStack(@Nullable final Collection <? extends ELEMENTTYPE> aCollection,
                                                                       @Nonnull final Predicate <? super ELEMENTTYPE> aFilter); @Nonnull @ReturnsMutableCopy static NonBlockingStack <ELEMENTTYPE> newStack(@Nullable final Collection <? extends ELEMENTTYPE> aValues); @Nullable @ReturnsMutableCopy static NonBlockingStack <ELEMENTTYPE> getStackCopyWithoutTop(@Nullable final NonBlockingStack <ELEMENTTYPE> aStack);  }### Answer:
@Test public void testNewStackSingleValue () { NonBlockingStack <String> aStack = StackHelper.newStack (); assertNotNull (aStack); aStack = StackHelper.newStack ("Hallo"); assertNotNull (aStack); assertEquals (1, aStack.size ()); assertTrue (aStack.contains ("Hallo")); assertEquals ("Hallo", aStack.peek ()); assertEquals ("Hallo", aStack.pop ()); }