@Nullable
            @Override
            public AggregatedHttpResponse renderStatus(@Nullable ServiceRequestContext ctx,
                                                       ServiceConfig config,
                                                       @Nullable RequestHeaders headers,
                                                       HttpStatus status,
                                                       @Nullable String description,
                                                       @Nullable Throwable cause) {
                final AggregatedHttpResponse response =
                        ServerErrorHandler.this.renderStatus(ctx, config, headers, status, description, cause);
                if (response != null) {
                    return response;
                }
                return other.renderStatus(ctx, config, headers, status, description, cause);
            }
Returns a newly created {@link ServerErrorHandler} that tries this {@link ServerErrorHandler} first and
then the specified {@link ServerErrorHandler} when the first call returns {@code null}.
<pre>{@code
ServerErrorHandler handler = (ctx, cause) -> {
    if (cause instanceof FirstException) {
        return HttpResponse.of(200);
    }
    return null;
}
assert handler.onServiceException(ctx, new FirstException()) != null;
assert handler.onServiceException(ctx, new SecondException()) == null;
assert handler.onServiceException(ctx, new ThirdException()) == null;

ServerErrorHandler combinedHandler = handler.orElse((ctx, cause) -> {
    if (cause instanceof SecondException) {
        return HttpResponse.of(200);
    }
    return null;
});

assert handler.onServiceException(ctx, new FirstException()) != null;
assert handler.onServiceException(ctx, new SecondException()) != null;
assert handler.onServiceException(ctx, new ThirdException()) == null;

// The default handler never returns null.
ServerErrorHandler nonNullHandler = combinedHandler.orElse(ServerErrorHandler.ofDefault());
assert handler.onServiceException(ctx, new FirstException()) != null;
assert handler.onServiceException(ctx, new SecondException()) != null;
assert handler.onServiceException(ctx, new ThirdException()) != null;
}</pre>
core/src/main/java/com/linecorp/armeria/server/ServerErrorHandler.java