# ADR-0008 - Use NullAway for null checking

## Status

- ACCEPTED on 2025-08-06

## Context

Our codebase uses `null` extensively to represent an absence of value or optionality of the argument.
We utilize nullness annotations in Java code and somewhat rely on IDE warnings to guide us.
However, the Java code we have is not fully annotated, which causes several consequences:
* IDE warnings can be misleading

- Use polite/formal address consistent with existing Ukrainian docs (use “ви/ваш”).
- Keep the tone concise and technical.
- Use one style of dashes. For example, if text contains "-" then use only this symbol to represent a dash.

### Headings

- Follow existing Ukrainian heading style; keep headings short and instructional.
- Do not add trailing punctuation to headings.

### Quotes

/// tip

You could use any other SQL or NoSQL database library you want (in some cases called <abbr title="Object Relational Mapper: a fancy term for a library where some classes represent SQL tables and instances represent rows in those tables">"ORMs"</abbr>), FastAPI doesn't force you to use anything. 😎

///

// Its value is the maximum value of the int64 type, which means that when the cache size is not specified,
// the cache can theoretically store as many elements as possible.
// (1 << 63) - 1 is the maximum value that an int64 type can represent.
const (
	defaultMaxSize = math.MaxInt
	// defaultTTL defines the default time-to-live (TTL) for each cache entry.
	// When the TTL for cache entries is not specified, each cache entry will expire after 24 hours.

                For example, a single string with:

                ```python
                "items:read items:write users:read profile openid"
                ````

                would represent the scopes:

                * `items:read`
                * `items:write`
                * `users:read`
                * `profile`
                * `openid`

                Read more about it in the

import com.google.errorprone.annotations.Immutable;
import java.util.Comparator;
import java.util.Map;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * Used to represent the order of elements in a data structure that supports different options for
 * iteration order guarantees.
 *
 * <p>Example usage:
 *
 * {@snippet :
 * MutableGraph<Integer> graph =

def decimal_encoder(dec_value: Decimal) -> int | float:
    """
    Encodes a Decimal as int if there's no exponent, otherwise float

    This is useful when we use ConstrainedDecimal to represent Numeric(x,0)
    where an integer (but not int typed) is used. Encoding this as a float
    results in failed round-tripping between encode and parse.
    Our Id type is a prime example of this.

 *
 * The full range of code points is 0..0x10fffe. We can represent any of these code points with 21
 * bits.
 *
 * We split each code point into a 14-bit prefix and a 7-bit suffix. All code points with the same
 * prefix are called a 'section'. There are 128 code points per section.
 *
 * Ranges Data (32,612 bytes)
 * ==========================
 *
 * Each entry is 4 bytes, and represents a _range_ of code points that all share a common 14-bit

```

Example:

Source (English):

```
<abbr title="Object Relational Mapper: a fancy term for a library where some classes represent SQL tables and instances represent rows in those tables">ORM</abbr>
```

Result (German):

```

    this.host = host;
    this.port = port;
    this.hasBracketlessColons = hasBracketlessColons;
  }

  /**
   * Returns the portion of this {@code HostAndPort} instance that should represent the hostname or
   * IPv4/IPv6 literal.
   *
   * <p>A successful parse does not imply any degree of sanity in this field. For additional
   * validation, see the {@link HostSpecifier} class.
   *