### Question:
AtomicDouble extends Number { public double get() { return Double.longBitsToDouble(value.get()); } AtomicDouble();  AtomicDouble(double init); double get(); double addAndGet(double amount); double getAndAdd(double amount); double getAndSet(double amount); boolean compareAndSet(double expect, double update); void set(double amount); void max(double v); @Override int intValue(); @Override long longValue(); @Override float floatValue(); @Override double doubleValue();  }### Answer:
@Test public void init() { AtomicDouble v = new AtomicDouble(); Assertions.assertEquals(0.0, v.get(), 1e-12); }
@Test public void initWithValue() { AtomicDouble v = new AtomicDouble(42.0); Assertions.assertEquals(42.0, v.get(), 1e-12); }