Java Code Review Checklist (2026): 7 Things to Check in Every PR

Skipping structured review on Java projects tends to surface as tightly coupled class hierarchies, unhandled exceptions, and unoptimized loops, the kind of issues that are cheap to catch in review and expensive to fix in production. A Java code review checklist should cover seven areas: readability, coding standards, exception handling, performance, test coverage, modularity, and API/database interaction. Below is a practical checklist for each, with good vs. bad code examples, plus the tools that help enforce them automatically.

That risk has only grown as more Java code ships AI-generated: agentic coding tools produce syntactically valid code fast, but they don’t know your team’s exception-handling conventions, your existing service boundaries, or which patterns your codebase has already standardized on. A checklist matters more, not less, when a growing share of what you’re reviewing wasn’t written by a person who read the last PR.

Why Java Specifically Needs Structured Code Review

Java’s object-oriented design, checked-exception model, and concurrency features create failure modes that a generic review misses:

• Class design: deep inheritance trees and tight coupling are easy to introduce and hard to unwind later.
• Exception handling: checked exceptions invite empty or overly broad try-catch blocks that swallow real errors.
• Concurrency: synchronized blocks, shared state, and concurrent collections are easy to get subtly wrong (deadlocks, race conditions).
• Security: insecure deserialization and improper encryption are common in Java’s most security-critical use cases (banking, fintech, government).

The Checklist

1. Code Readability and Maintainability

• Validate that the code is easy to read and understand.
• Validate whether the variables and methods used adhere to Java naming conventions.

Ensure comments are clear, relevant, concise, and consistent in formatting and indentation.

// Bad
int x = 1;
if (x == 1) {
    System.out.println("Yes");
}

// Good
int userStatus = 1;

if (userStatus == 1) {
    System.out.println("User is active");
}

2. Adherence to Coding Standards

• Validate that the code aligns with the standard Java conventions like indentation, line length, use of spaces, etc.

Ensure consistency in the naming and organization of classes, methods, and variables.

// Bad

public class myclass{
public void getdata( ){System.out.println("data");}}

// Good

public class MyClass {

    public void getData() {
        System.out.println("data");
    }
}

3. Error Handling and Exception Management

• Validate that exceptions are well handled with meaningful messages.

Ensure a clear strategy exists for exception propagation, logging, and recovery.

// Bad

try {
    int result = 10 / 0;
} catch (Exception e) {
    e.printStackTrace();
}

// Good

try {
    int result = 10 / 0;
} catch (ArithmeticException e) {
    System.err.println("Cannot divide by zero: " + e.getMessage());
    // Log exception properly here
}

4. Code Performance, Optimization, and Efficiency

• Ensure that loops, redundant computations, and resource management are implemented efficiently.
• Suggest refinements for code performance without sacrificing readability.

Look for potential memory leaks or excessive object creation.

// Bad (redundant loop)

List<String> names = getNames();
for (int i = 0; i < names.size(); i++) {
    System.out.println(names.get(i));
}

// Good

List<String> names = getNames();
for (String name : names) {
    System.out.println(name);
}

5. Unit Tests and Test Coverage

• Ensure that tests cover both happy paths and edge cases.
• Validate that unit tests are independent, automated, and run consistently.
• Ensure meaningful assertions are used, and always check if the expected outcome is met.
  

// Bad
 @Test
 public void testCalculateTax() {
 double result = calculateTax(1000);
 // no assertion
 }
// Good
 @Test
 public void testCalculateTax_returnsCorrectAmount() {
 double result = calculateTax(1000);
 assertEquals(180.0, result, 0.01);
 }
@
 public void testCalculateTax_zeroSalary() { assertEquals(0.0, calculateTax(0), 0.01);
 }

6. Code Modularity and Reusability

• Ensure the methods/classes used are small and have a single responsibility.

Ensure that the redundant code has been refactored into reusable methods.

// Bad
public void calculateTax() {
    double tax = salary * 0.18;
    System.out.println("Tax: " + tax);
}

// Good

public double calculateTax(double salary) {
    return salary * 0.18;
}

Ensure that design patterns like Factory and Singleton are used where applicable, for example, replacing scattered new PaymentProcessor(…) calls across the codebase with a single PaymentProcessorFactory.create(type) method.

7. API and Database Interaction

• Validate that API calls are handled asynchronously.
• Ensure SQL queries are optimized for enhanced performance.
• Check if proper indexing and caching mechanisms are used.

// Bad (blocking call, unindexed lookup)
 public User getUserById(String id) {
 return jdbcTemplate.queryForObject(
 "SELECT * FROM users WHERE id = '" + id + "'", User.class);
 }
// Good
 public CompletableFuture<User> getUserById(String id) {
 return CompletableFuture.supplyAsync(() ->
 jdbcTemplate.queryForObject(
 "SELECT * FROM users WHERE id = ?", new Object[]{id}, User.class));
 }
 // Assumes an index exists on users.id

Java Code Review Tools

Teams often pair a static analyzer (SonarQube, PMD) with Qodo’s agentic review: the static tool catches known patterns, while Qodo uses full codebase context and PR history to catch context-dependent issues, breaking changes, architectural drift, and duplicated logic that neither a linter nor a diff-level skim would surface. Rule Miner can automatically turn checklist items like the ones above into enforced rules, mined from how your team has actually flagged issues in past PRs, rather than relying on every reviewer to check each item by hand. For a deeper look at reviewing AI-generated code specifically, see Qodo’s Academy chapter on AI code review.

Why This Checklist Pays Off (and Where Reviews Go Wrong)

Teams that run this checklist consistently see fewer production bugs, faster delivery cycles, and less rework. Most of that gain comes from closing off the same handful of failure modes that erode review quality over time: reviews rushed at the end of a sprint, small issues waved through because nobody wants to be the reviewer who nitpicks, and feedback vague enough that the author can’t act on it (“this is bad” tells them nothing about what to fix or why).

The fix isn’t more review, it’s more structure. Timebox reviews so they don’t get squeezed into the last ten minutes before a merge. Keep PRs small enough that a reviewer can actually hold the change in their head. Use this checklist instead of relying on memory, especially as more of what’s being reviewed was written by an agent rather than a teammate. And when something’s wrong, say specifically what and why, not just that it is.

FAQs

1. Why is code review critical for Java projects?

Code reviews help catch bugs early, improve code quality, ensure consistency, and promote knowledge sharing across the team. In Java projects, they also help maintain strict type safety and adherence to object-oriented design principles.

2. How do I ensure Java code readability during a review?

Look for clear variable and method names, proper indentation, consistent formatting, and meaningful comments. Encourage short, focused methods and avoid deeply nested logic.

3. How can I enforce Java coding standards in my team?

Use tools like Checkstyle, PMD, or SonarQube to automatically flag violations. Set up shared formatting rules in the IDE and make coding standards part of the review checklist.

4. How do I review Java code for proper unit testing?

Check if tests cover both normal and edge cases. Ensure they are isolated and repeatable and use clear assertions. Also, verify the use of mocking frameworks such as Mockito to test dependencies.