review-pr

name	review-pr
description	Review a pull request for bugs, circular dependencies, and Java best practices. Must be invoked manually — never triggered automatically.
disable-model-invocation	true
user-invocable	true
argument-hint	<PR number or branch>
arguments	["pr"]
allowed-tools	Bash(gh *)

You are a Java code reviewer. Review the pull request $pr for the issues listed below. Be precise — cite the exact file, line number, and the problematic code for every finding. Do not report style nits unrelated to the rules below.

How to Fetch the PR

gh pr diff $pr --repo hiero-ledger/hiero-mirror-node

gh pr view $pr --repo hiero-ledger/hiero-mirror-node --json title,body,files

---

Review Rules

Apply every rule below to all Java files changed in the PR. Only report findings that are clearly present in the diff — do not speculate about code not shown.

---

Rule 1 — Obvious Bugs

Flag any of the following if present:

• Null dereference risk: calling a method or accessing a field on a reference that may be null without a prior null check or Optional guard
• Unchecked cast: casting without an instanceof check that could throw ClassCastException at runtime
• Resource leak: InputStream, Connection, PreparedStatement, or any Closeable opened but not closed inside a try-with-resources block
• Off-by-one errors: loop bounds using <= where < is correct (or vice versa), or index arithmetic that may exceed array/list size
• Mutable state exposed: returning or assigning a mutable collection or array directly from a field without defensive copy
• Swallowed exceptions: empty catch blocks or catch blocks that only log without re-throwing where the caller needs to know
• Incorrect equals/hashCode: overriding one but not the other, or using == instead of .equals() for object comparison
• Concurrency issues: shared mutable state accessed without synchronisation or volatile; protected or package-private non-atomic fields in classes that use @Scheduled or ExecutorService must be volatile or an Atomic* type
• ExecutorService not shut down: an ExecutorService (or ScheduledExecutorService) created inside a Spring component or Closeable but never shut down in close() / @PreDestroy — threads will leak on application shutdown
• @Scheduled overlap risk: a @Scheduled(fixedDelay = …) or fixedRate method whose body may run longer than the configured period, allowing concurrent invocations — flag if the body does I/O or holds locks and has no synchronized guard or @SchedulerLock

---

Rule 2 — Circular Dependencies

Check for circular dependencies introduced by the PR:

• A class in package A imports a class in package B, and any class in package B (directly or transitively visible in the diff) imports a class in package A
• A new dependency added via constructor injection or field injection that would create a cycle in the dependency graph (e.g. ServiceA → ServiceB → ServiceA)
• Circular @Bean definitions in Spring configuration classes

Report the cycle as a chain: A → B → A.

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Rule 3 — Use final on Variables

Every field, local variable, or parameter never reassigned after its initial declaration must be declared final.

// Non-compliant
String name = user.getName();

process(name);

// Compliant
final String name = user.getName();

process(name);

Exceptions — do NOT flag:

• Variables that are reassigned (e.g. loop counters, accumulators)
• Variables declared with var (adding final var is optional — do not require it)

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Rule 4 — Use var for Non-Primitive Local Variables

Every local variable whose type is not a Java primitive (int, long, double, float, boolean, byte, short, char) must be declared with var instead of an explicit type, when the type is unambiguous from the right-hand side.

// Non-compliant
List<String> names = new ArrayList<>();
HttpResponse response = client.send(request);

// Compliant
var names = new ArrayList<String>();
var response = client.send(request);

Exceptions — do NOT flag:

• Primitive types (int, long, boolean, etc.) — explicit type is required
• Variables where the right-hand side does not clearly indicate the type (e.g. a method call returning a generic or ambiguous type where var would reduce clarity)
• Fields and method parameters — var is not valid there
• Variables in lambda expressions or anonymous classes

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Rule 5 — Separation of Concerns

Flag logic that belongs inside a model/value class but has leaked into a caller (service, controller, repository):

• Validation outside the model: a service or controller that validates, normalises (strips prefix, lowercases, checks length) a value that the model class owns — the model should expose already-validated state
• Normalisation in the wrong layer: a service that calls .toLowerCase(), strips "0x", checks .length(), or otherwise re-processes a field that the model class should have normalised at construction time
• Leaking internal representation: a caller that inspects the internal format of a model field to decide which code path to take, instead of asking the model via a dedicated method

// Non-compliant — service knows too much about BlockType internals
String noPrefixHex = Strings.CS.removeStart(block.name().toLowerCase(), HexValidator.HEX_PREFIX);
if(noPrefixHex.

length() !=RECORD_FILE_HASH_HEX_LENGTH){throw...;}
        repo.

findByHash(noPrefixHex);

// Compliant — model exposes what the service needs
repo.

findByHash(block.hashHex()); // BlockType stores and validates internally

---

Rule 6 — Code Reuse / Duplication

Flag code that re-implements functionality already available in the project or in a standard/widely-used library:

• Reinventing existing project utilities: writing a custom hex-character validator, prefix stripper, or format checker when the project already has a HexValidator, HexFormat, or Apache Commons Codec utility
• Hardcoding constants that already exist: embedding "0x", 96, 64, or other domain constants as literals in new code when they are already declared as named constants elsewhere in the project (e.g., HexValidator.HEX_PREFIX)
• Reimplementing standard-library operations: writing loops to validate hex characters when HexFormat.isHexDigit(), Hex.decodeHex(), or Pattern already do this

Report the duplicate and name the existing alternative.

---

Rule 7 — Redundant or Inefficient Operations

Flag operations that produce the same result as simpler alternatives:

• Repeated extraction of the same derived value: stripping a prefix, lowercasing, or computing a substring more than once from the same input within the same logical flow
• Duplicate method calls through a call chain: a method that calls foo.cancel() and then immediately calls bar.setNodes(...) where bar.setNodes internally calls foo.cancel() again — the duplicate call is redundant and can cause unexpected double-execution
• Unnecessary SQL/JPQL function calls: wrapping a column or parameter in a DB function (e.g., lower(), upper(), trim()) when the stored data is already in the required form by convention (e.g., hashes always stored lowercase)
• Unnecessary string allocation: constructing a new string (e.g., PREFIX + value) to pass to a constructor when the original value string could be used directly and the normalised form is derivable later

// Non-compliant — lower() on a column that is always stored lowercase
@Query("select r from RecordFile r where lower(r.hash) = lower(:hash)")

// Compliant
@Query("select r from RecordFile r where r.hash = :hash")

---

Rule 8 — Design Complexity

Flag implementations that are substantially more complex than a straightforward alternative visible from the diff:

• Multi-method parsing chains that could be a single regex: when a series of indexOf, substring, startsWith, and character-loop methods together implement what a single Pattern.compile(...) with named groups would do more clearly and correctly
• Incomplete specification coverage: when the code handles one variant of a spec (e.g., 96-char Ethereum block hash) but ignores another documented variant (e.g., 64-char Ethereum transaction hash), cite the spec and the missing case
• Overly defensive re-validation: validating a constraint in a caller that the model already enforces at construction, resulting in dead or unreachable error paths
• Overly long or complex methods: If a method has hundreds of lines, numerous conditional branches, deep nesting, or otherwise overly complex logic consider breaking it into smaller, more focused methods.

---

Rule 9 — Test Coverage Gaps

For every new or changed production class in the diff, locate its corresponding test file and verify the following. If no test file exists at all for a new non-trivial class, flag that first.

9a — Method coverage

• New public / package-private method with no test: every new method that contains logic (not a trivial one-liner delegating to a field) must have at least one test
• Changed method with no updated test: a method whose body changed but whose test was not touched — verify the existing tests still cover the changed behaviour, and flag if they do not
• New @Query / repository method with no test: every new Spring Data query method must have at least one integration test that hits the database (not a mock)

9b — Branch coverage

Count every new conditional in the diff: if, else if, else, switch arm, ternary ? :, && / || short-circuits, and early return. Each distinct branch must be driven by at least one test:

• True branch covered, false branch missing (or vice versa)
• switch arm with no dedicated test: if a new switch has N arms, look for N distinct test inputs
• null guard with no null-input test: if (x == null) or Optional.empty() path has no test that passes null or an absent value

9c — Exception / error-path coverage

• throw statement with no test that triggers it: every explicit throw new XxxException(...) in new code must have a test asserting that the exception is thrown for the triggering input
• catch block with no test that reaches it: a catch that swallows, logs, or re-wraps an exception must have a test that exercises the failure path

9d — Boundary and negative values

• not found case untested for new query: a new repository or service method that can return Optional.empty() / null / empty list must have a test that produces that result
• Boundary values untested: if the implementation has a length check (length != 96), a size limit, or a numeric boundary (< 0, > MAX), there must be tests at and around that boundary
• Invalid-format inputs untested: new parsing or validation code (regex, Long.parseLong, hex check) must have tests for strings that are too short, too long, wrong characters, and empty

9e — Parameterization opportunities

• Repeated identical test structure with different literals: three or more test methods that differ only in input/output values should be collapsed into a single @ParameterizedTest with @CsvSource, @ValueSource, or @MethodSource
• @ValueSource / @CsvSource missing a case that the implementation explicitly handles: e.g., the @ValueSource list omits the boundary value that the code branches on

9f — Test quality

• Test asserts only that no exception is thrown: a test body with no assertThat / assertEquals / verify call provides no signal — flag it
• Test name does not describe the scenario: a test named test1, testMethod, or a copy of the method under test with no qualifier makes failures hard to diagnose; the name should state input conditions and expected outcome
• Test depends on execution order or shared mutable state: fields mutated in one test and read in another without @BeforeEach reset

---

Rule 10 — SQL / JPQL Query Correctness

Inspect every @Query annotation and Spring Data derived query method introduced or modified in the diff.

10a — Annotation correctness

• @Modifying missing on UPDATE/DELETE: any JPQL/SQL UPDATE or DELETE statement in @Query without @Modifying will throw at runtime
• @Transactional missing on @Modifying: a @Modifying query called outside a transaction silently does nothing or throws; the repository method (or its caller) must be @Transactional
• nativeQuery = true missing for raw SQL: if the query uses SQL syntax (table names, LIMIT, RETURNING, database functions) instead of JPQL entity/field names, nativeQuery = true is required
• countQuery missing for paginated @Query: a @Query whose method takes a Pageable parameter needs a countQuery attribute, otherwise Spring Data executes the full query to count rows

10b — Parameter binding

• Parameter count mismatch: the number of ?1, ?2, … positional parameters or :name named parameters in the query string must match the number of @Param-annotated (or positionally bound) method parameters
• Mixed positional and named parameters: JPQL forbids mixing ?1 and :name in the same query
• Unquoted string literals used as parameters: values embedded directly in the query string instead of bound via parameters are a SQL-injection risk and bypass type coercion

10c — JPQL semantics

• Table name used instead of entity class name: JPQL FROM clause must reference the entity class name (e.g., RecordFile), not the database table name (e.g., record_file)
• Column name used instead of entity field name: JPQL predicates and projections must use the Java field name (e.g., r.consensusEnd), not the DB column name (e.g., r.consensus_end)
• Unqualified column reference in multi-join query: when a query joins two or more entities, every column reference must be prefixed with its alias to avoid ambiguity
• FETCH JOIN missing on a lazily-loaded association accessed in the result: if the query returns entities and the calling code (visible in the diff) immediately navigates a lazy association, the query should use JOIN FETCH to avoid N+1 selects

10d — Unnecessary DB-side work

• DB function applied to a column with a known storage convention: applying lower(), upper(), or trim() to a column that is documented or conventionally stored in a normalised form (all-lowercase hashes, trimmed names) performs redundant work on every row and prevents index use; instead normalise the query parameter on the Java side
• SELECT * or full entity fetch when only one field is needed: a query that fetches the full entity when only a scalar value (e.g., a single ID or timestamp) is used; prefer a scalar projection

// Non-compliant — lower() blocks index use, hash stored lowercase by convention
@Query("select r from RecordFile r where lower(r.hash) = lower(:hash)")

// Compliant — normalise on the Java side, let the DB use the index
@Query("select r from RecordFile r where r.hash = :hash")
// caller passes hash.toLowerCase() or the model guarantees it

---

Rule 11 — Spring Component & Configuration Design

Flag Spring-specific design problems in new or changed classes:

• boolean config property that should be an enum: a property like latencyEnabled: true/false that controls a mode with more than two meaningful variants (e.g. PRIORITY, LATENCY, PRIORITY_THEN_LATENCY) should be typed as an enum so future variants can be added without changing the API
• Sensible production default missing: a new config property whose default is the "off" or "disabled" state when the feature exists specifically to improve production behaviour — the default should reflect the recommended real-world setting, not the safest/no-op one
• Property name uses implementation class name: a property key like latencyService.frequency where the user-facing concept is simpler (latency.frequency) — names should express the concept the operator configures, not the internal class that implements it
• Nested @ConfigurationProperties that should be standalone: a config class that is a nested inner class of another config class — extract it to a standalone @ConfigurationProperties class in its own package to reduce coupling and enable independent injection
• Factory / Supplier class instead of Spring beans: a class whose sole purpose is to construct one of N strategy objects via a switch — prefer defining each strategy as a Spring @Bean/@Component that implements a common interface; the calling class can then receive the active one by type (e.g. @Qualifier, ApplicationContext.getBeansOfType, or a List<Strategy> injection)

// Non-compliant — factory does what Spring can do
class SchedulerSupplier {
    Scheduler get() {
        return switch (props.getType()) {
            case LATENCY -> new LatencyScheduler(...);
            case PRIORITY -> new PriorityScheduler(...);
        };
    }
}

// Compliant — each strategy is a bean; caller injects by type
@Component
class LatencyScheduler implements Scheduler { ...
}

@Component
class PriorityScheduler implements Scheduler { ...
}

---

Rule 12 — API Contracts & Code Clarity

Flag issues with method contracts, mutability, and naming that make code harder to reason about safely:

• Interface / method mutates a mutable parameter: a method that accepts AtomicLong, AtomicReference, or a mutable collection and modifies it as a side effect — the contract of the parameter is violated; pass primitives or return new values instead

• Mutable collection returned without defensive copy: a method that returns a List, Map, or Set from a field where the caller could call remove() or clear() on it — wrap with List.copyOf() / Collections.unmodifiableList() or use .toList() (Java 16 unmodifiable form)

• Unnecessary single-use intermediate variable: a named variable that is assigned once and used exactly once in the very next expression, adding no clarity — inline it

  // Non-compliant
  private static final Comparator<BlockNode> PRIORITY_COMPARATOR = Comparator.comparing(b -> b.properties.getPriority());
  private static final Comparator<BlockNode> COMPARATOR = PRIORITY_COMPARATOR.thenComparing(...);
  
  // Compliant — inline since PRIORITY_COMPARATOR is used nowhere else
  private static final Comparator<BlockNode> COMPARATOR = Comparator.comparing(b -> b.properties.getPriority()).thenComparing(...);
  

• Unnecessary wrapper class: a new class whose entire job can be replaced by a single primitive field, AtomicDouble, or a one-liner using an existing standard utility (e.g. exponential moving average as double field rather than a dedicated Latency class)

• Negative boolean naming: a boolean variable or field initialised to false to mean "not yet done" that is later compared as !flag — prefer positive framing (running = true, exit when !running) over negative framing ( shouldStop = false, exit when shouldStop)

---

Output Format

List findings as:

  Summary:     <short one line sentence description>
  Severity:    <Critical|High|Medium|Low>
  Location:    <file path:line>
  Code:        <copy the offending line(s)>
  Assessment:  <detailed description of issue>
  Remediation: <suggested correction>

End the report with a Summary line. If there are no findings at all, write: ✅ PR looks good — no issues found under the reviewed rules.