### Question:
PrimitiveLongWrapper extends LongWrapper { @Override public void set(Number v) { set(v == null ? defaultValue : v.longValue()); } PrimitiveLongWrapper();  PrimitiveLongWrapper(long value); @Override void set(Number v); @Override Long getDefault(); @Override boolean isPrimitiveWrapper(); @Override R accept(WrapperVisitor<R, P, Q, TH> visitor, P p, Q q);  }### Answer:
@Test void set() { PrimitiveLongWrapper wrapper = new PrimitiveLongWrapper(); wrapper.set(10); assertEquals(10L, wrapper.get()); wrapper.set(new BigDecimal(20)); assertEquals(20L, wrapper.get()); }
@Test void set_null() { PrimitiveLongWrapper wrapper = new PrimitiveLongWrapper(); wrapper.set(null); assertEquals(0L, wrapper.get()); wrapper.set((Number) null); assertEquals(0L, wrapper.get()); }