### Question:
ImmutableCharacterEncoding implements CharacterEncoding { @Override public int hashCode() { return Objects.hashCode(this.charset); } ImmutableCharacterEncoding(Charset charset); @Override boolean isWildcard(); @Override String name(); @Override Charset charset(); @Override String toHeader(); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString();  }### Answer:
@Test public void wildcardCharacterEncodingsHaveSameHashCode() { assertThat(wildcard().hashCode(),equalTo(wildcard().hashCode())); }
@Test public void equalRegularCharacterEncodingsHaveSameHashCode() { assertThat(regular().hashCode(),equalTo(regular().hashCode())); }
@Test public void differentRegularCharacterEncodingsHaveDifferentHashCode() { assertThat(regular().hashCode(),not(equalTo(alternative().hashCode()))); }