IllegalNumberArgumentException extends RuntimeException implements IllegalArgumentHolder<CharSequence> { @Override public CharSequence getIllegalArgument() { return illegalArgumentValue; } IllegalNumberArgumentException(@Nullable final CharSequence illegalArgumentValue);  IllegalNumberArgumentException(@Nullable final CharSequence illegalArgumentValue, @Nullable final Throwable cause);  IllegalNumberArgumentException(@Nullable final String argumentName, @Nullable final CharSequence illegalArgumentValue);  IllegalNumberArgumentException(@Nullable final String argumentName, @Nullable final CharSequence illegalArgumentValue,
			@Nullable final Throwable cause); @Override CharSequence getIllegalArgument();  }
@Test public void testGetIllegalArgument() { final IllegalArgumentHolder<CharSequence> iah = new IllegalNumberArgumentException("42a"); Assert.assertEquals("42a", iah.getIllegalArgument()); }