### Question:
MapType extends AbstractType { @Override public String getDisplayName() { return "map(" + keyType.getDisplayName() + ", " + valueType.getDisplayName() + ")"; } MapType(Type keyType, Type valueType, TypeOperators typeOperators); @Override TypeOperatorDeclaration getTypeOperatorDeclaration(TypeOperators typeOperators); @Override BlockBuilder createBlockBuilder(BlockBuilderStatus blockBuilderStatus, int expectedEntries, int expectedBytesPerEntry); @Override BlockBuilder createBlockBuilder(BlockBuilderStatus blockBuilderStatus, int expectedEntries); Type getKeyType(); Type getValueType(); @Override boolean isComparable(); @Override Object getObjectValue(ConnectorSession session, Block block, int position); @Override void appendTo(Block block, int position, BlockBuilder blockBuilder); @Override Block getObject(Block block, int position); @Override void writeObject(BlockBuilder blockBuilder, Object value); @Override List<Type> getTypeParameters(); @Override String getDisplayName(); Block createBlockFromKeyValue(Optional<boolean[]> mapIsNull, int[] offsets, Block keyBlock, Block valueBlock); MethodHandle getKeyNativeHashCode(); MethodHandle getKeyBlockHashCode(); MethodHandle getKeyBlockNativeEqual(); MethodHandle getKeyBlockEqual();  }### Answer:
@Test public void testMapDisplayName() { TypeOperators typeOperators = new TypeOperators(); MapType mapType = new MapType(BIGINT, createVarcharType(42), typeOperators); assertEquals(mapType.getDisplayName(), "map(bigint, varchar(42))"); mapType = new MapType(BIGINT, VARCHAR, typeOperators); assertEquals(mapType.getDisplayName(), "map(bigint, varchar)"); }