class FailingNonNull { private final String nullable; public FailingNonNull() { Inner inner = new Inner(); inner.doNullableStuff(); nullable = "now non-null"; } private class Inner{ public void doNullableStuff() { if (nullable !=null) { //Condition 'nullable!=null' is always 'true' System.out.println(nullable.length()); } } } public static void main(String[] args) { new FailingNonNull(); } }