### Question:
ImmutableMapParameter implements Map<K, V> { @Override public V put(K key, V value) { throw new UnsupportedOperationException(UNMODIFIABLE_MESSAGE); } private  ImmutableMapParameter(Map<K, V> map); static Builder<K, V> builder(); static ImmutableMapParameter<K, V> of(K k0, V v0); static ImmutableMapParameter<K, V> of(K k0, V v0, K k1, V v1); static ImmutableMapParameter<K, V> of(K k0, V v0, K k1, V v1, K k2, V v2); static ImmutableMapParameter<K, V> of(K k0, V v0, K k1, V v1, K k2, V v2, K k3,
            V v3); static ImmutableMapParameter<K, V> of(K k0, V v0, K k1, V v1, K k2, V v2, K k3,
            V v3, K k4, V v4); @Override boolean containsKey(Object key); @Override boolean containsValue(Object value); @Override Set<Entry<K, V>> entrySet(); @Override V get(Object key); @Override boolean isEmpty(); @Override Set<K> keySet(); @Override int size(); @Override Collection<V> values(); @Override void clear(); @Override V put(K key, V value); @Override @SuppressWarnings("checkstyle:hiddenfield") void putAll(Map<? extends K, ? extends V> map); @Override V remove(Object key);  }### Answer:
@Test public void testErrorOnDuplicateKeys() { try { Map<Integer, String> builtMap = new ImmutableMapParameter.Builder<Integer, String>() .put(1, "one") .put(1, "two") .build(); fail("IllegalArgumentException expected."); } catch (IllegalArgumentException iae) { } catch (Exception e) { fail("IllegalArgumentException expected."); } }