How to Eliminate Logging Boilerplate in Java with CDI Interceptors

Introduction

Logging is essential for monitoring, debugging, and performance analysis.

However, manually adding log statements to every method creates several problems:

• Code Clutter: Business logic becomes obscured by logging code
• Inconsistency: Different developers log in different ways
• Maintenance Burden: Changing log format requires updating every method
• Incomplete Implementation: Easy to forget important details like execution time, exception handling, or parameter logging

CDI Interceptors solve these problems by applying the Aspect-Oriented Programming (AOP) principle, separating cross-cutting concerns from business logic.

With CDI interceptors, you can add logging to any method with a single annotation without requiring any manual coding for logging!

In this article, we’ll build a production-ready logging interceptor that automatically captures:

• Method entry with parameter values
• Method exit with return values
• Execution time in milliseconds
• Exception details with execution time

What Are CDI Interceptors?

CDI (Contexts and Dependency Injection) Interceptors allow you to intercept method calls and execute code before and after the target method runs. They’re useful for cross-cutting concerns like:

• Logging: Automatic method tracing
• Security: Authorization checks
• Transaction Management: Begin/commit transactions
• Performance Monitoring: Method execution timing
• Caching: Cache method results
• Validation: Pre/post-condition checks

How Interceptors Work

Client calls method
          │
          ▼
   ┌─────────────────┐
   │  @Logged        │ ◄──Annotation triggers interceptor
   │  PaymentService │
   └────────┬────────┘
            │
            ▼
   ┌─────────────────────────┐
   │  LoggingInterceptor     │ ◄── Intercepts the call
   │  @AroundInvoke          │
   │                         │
   │  1. Log entry + params  │
   │  2. Start timer         │
   │  3. context.proceed()   │ ◄── Execute actual method
   │  4. Log exit + duration │
   │  5. Return result       │
   └─────────────────────────┘
            │
            ▼
      Return to client

Step 1: Create the Interceptor Binding Annotation

First, we define a custom annotation that will mark which methods/classes should be logged.

package jakartaee.cdi.tutorial.store.payment.interceptor;

import jakarta.interceptor.InterceptorBinding;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
 * Interceptor binding annotation for automatic method logging.
 *
 * Apply this annotation to methods or classes to automatically log:
 * - Method entry with parameters
 * - Method exit with return value
 * - Execution time in milliseconds
 * - Any exceptions thrown
 *
 * Usage:
 *   @Logged  // On a class - logs all public methods
 *   public class PaymentService { ... }
 *
 *   @Logged  // On a method - logs only this method
 *   public void processPayment(...) { ... }
 */
@InterceptorBinding                     (1)
@Target({ElementType.TYPE,              (2)
         ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)     (3)
public @interface Logged {
}

1. The @InterceptorBinding marks this as an interceptor binding annotation (not just a regular annotation).

2. The @Target can be applied to classes (TYPE) or methods (METHOD)

3. @Retention(RUNTIME) - Must be available at runtime for CDI to process it

Common Mistake: Forgetting @InterceptorBinding will cause CDI to ignore the annotation, and no logging will occur!

Step 2: Implement the Logging Interceptor

Now we create the interceptor that performs the actual logging.

package jakartaee.cdi.tutorial.store.payment.interceptor;

import jakarta.annotation.Priority;
import jakarta.interceptor.AroundInvoke;
import jakarta.interceptor.Interceptor;
import jakarta.interceptor.InvocationContext;

import java.util.Arrays;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Logging interceptor that automatically logs method entry, exit, and execution time.
 *
 * This interceptor is applied to any method or class annotated with @Logged.
 */
@Logged                                    (1)
@Interceptor                               (2)
@Priority(Interceptor.Priority.APPLICATION) (3)
public class LoggingInterceptor {
    @AroundInvoke                          (4)
    public Object logMethodCall(InvocationContext context) throws Exception {
        // Get method metadata
        final String className = context.getTarget().getClass().getName();
        final String methodName = context.getMethod().getName();
        final Logger logger = Logger.getLogger(className);  (5)
        // Log method entry with parameters
        logger.log(Level.INFO, "Entering method: {0}.{1} with parameters: {2}",
                new Object[]{className, methodName, Arrays.toString(context.getParameters())});
        // Start timing
        final long startTime = System.currentTimeMillis();
        try {
            // Execute the actual method
            Object result = context.proceed();  (6)
            // Calculate execution time
            final long executionTime = System.currentTimeMillis() - startTime;
            // Log successful exit
            logger.log(Level.INFO, "Exiting method: {0}.{1}, execution time: {2}ms, result: {3}",
                    new Object[]{className, methodName, executionTime, result});
            return result;  (7)
        } catch (Exception e) {
            // Log exceptions with execution time
            final long executionTime = System.currentTimeMillis() - startTime;
            logger.log(Level.SEVERE, "Exception in method: {0}.{1}, execution time: {2}ms, exception: {3}",
                    new Object[]{className, methodName, executionTime, e.getMessage()});
            // Re-throw the exception to preserve normal error handling
            throw e;  (8)
        }
    }
}

1. The @Logged interceptor MUST be annotated with the binding annotation

2. @Interceptor marks this class as an interceptor

3. @Priority defines execution order when multiple interceptors exist (required in Jakarta EE 10)

4. @AroundInvoke: The method that wraps the target method call.

5. Uses the target class’s logger (better for filtering logs)

6. context.proceed(): executes the actual business method

7. Return the original method’s result

8. Re-throw exceptions to maintain normal error flow

Key Implementation Details

Why final variables?

The final keyword ensures that values don’t change during execution, which helps the Java Virtual Machine (JVM) optimize the code.

Why Arrays.toString()?

Converting parameters to strings prevents calling toString() on null objects, which would cause NullPointerException.

Why create a logger per method?

Using the target class’s logger(Logger.getLogger(className)) allows filtering logs by package or class in production logging configurations.

Step 3: Configure CDI to Enable the Interceptor

CDI requires explicit registration of interceptors in beans.xml.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="https://jakarta.ee/xml/ns/jakartaee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee
                           https://jakarta.ee/xml/ns/jakartaee/beans_4_0.xsd"
       version="4.0"
       bean-discovery-mode="all">  (1)
    <interceptors>  (2)
        <class>jakartaee.cdi.tutorial.store.payment.interceptor.LoggingInterceptor</class>
    </interceptors>
</beans>

1. The bean-discovery-mode="all" - Scan all classes for CDI beans

2. Register the interceptor (order matters if you have multiple interceptors)

Common Mistake: Forgetting to add the interceptor to beans.xml is the #1 reason why interceptors don’t work! The application will compile and run, but no logging will occur.

Step 4: Use the @Logged Annotation

Now you can apply automatic logging to your services!

Option 1: Apply to Entire Class

package jakartaee.cdi.tutorial.store.payment.service;

import jakartaee.cdi.tutorial.store.payment.interceptor.Logged;
import jakarta.enterprise.context.ApplicationScoped;
import jakarta.inject.Inject;
/**
 * Payment service with automatic logging on ALL public methods.
 * No manual logging code needed!
 */
@ApplicationScoped
@Logged  // <-- All public methods automatically logged
public class PaymentService {
    @Inject
    private IdempotencyService idempotencyService;
    // Automatically logged: entry, parameters, exit, result, duration
    public boolean processPayment(PaymentDetails paymentDetails) {
        // Pure business logic - no logging code!
        if (!validatePaymentDetails(paymentDetails)) {
            return false;
        }
        // Simulate payment processing
        return true;
    }
    // Also automatically logged
    public boolean validatePaymentDetails(PaymentDetails details) {
        return details != null &&
               details.getCardNumber() != null &&
               details.getAmount() != null;
    }
}

Option 2: Apply to Specific Methods

package jakartaee.cdi.tutorial.store.payment.resource;

import jakartaee.cdi.tutorial.store.payment.interceptor.Logged;
import jakarta.enterprise.context.ApplicationScoped;
import jakarta.inject.Inject;
import jakarta.ws.rs.*;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.Response;

@ApplicationScoped
@Path("/payments")
public class PaymentResource {
    @Inject
    private PaymentService paymentService;
    // Only this method is logged
    @POST
    @Path("/process")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    @Logged  // <-- Selective logging
    public Response processPayment(PaymentDetails paymentDetails) {
        boolean success = paymentService.processPayment(paymentDetails);
        if (success) {
            return Response.ok()
                    .entity("{\"status\": \"success\"}")
                    .build();
        } else {
            return Response.status(Response.Status.BAD_REQUEST)
                    .entity("{\"status\": \"failed\"}")
                    .build();
        }
    }
    // This method is NOT logged (no @Logged annotation)
    @GET
    @Path("/health")
    public Response health() {
        return Response.ok("UP").build();
    }
}

Testing the Logging Interceptor

1. Start the Application

cd payment
mvn liberty:dev
The application will start on http://localhost:9080

2. Make a Test Request

curl -X POST http://localhost:9080/payment/api/payments/process \


  -H "Content-Type: application/json" \
  -d '{
    "cardNumber": "4111111111111111",
    "cardHolderName": "John Doe",
    "expiryDate": "12/25",
    "securityCode": "123",
    "amount": 99.99
  }'

3. Observe the Automatic Logs

You should see output as below:

INFO: Entering method: jakartaee.cdi.tutorial.store.payment.service.PaymentService.processPayment
      with parameters: [PaymentDetails(cardNumber=4111111111111111, cardHolderName=John Doe,
      expiryDate=12/25, securityCode=123, amount=99.99)]
INFO: Entering method: jakartaee.cdi.tutorial.store.payment.service.PaymentService.validatePaymentDetails
      with parameters: [PaymentDetails(cardNumber=4111111111111111, ...)]
INFO: Exiting method: jakartaee.cdi.tutorial.store.payment.service.PaymentService.validatePaymentDetails,
      execution time: 2ms, result: true
INFO: Exiting method: jakartaee.cdi.tutorial.store.payment.service.PaymentService.processPayment,
      execution time: 45ms, result: true

Notice:

• No manual logging code in the business methods

• Nested method calls are tracked (validatePaymentDetails called from processPayment)

• Execution time automatically measured

• Parameters and results captured

• Clean separation between business logic and logging

4. Test Exception Handling

Trigger a validation error:

curl -X POST http://localhost:9080/payment/api/payments/process \
  -H "Content-Type: application/json" \
  -d '{
    "cardNumber": null,
    "amount": 99.99
  }'

Log output:

INFO: Entering method: jakartaee.cdi.tutorial.store.payment.service.PaymentService.processPayment
      with parameters: [PaymentDetails(cardNumber=null, amount=99.99)]
SEVERE: Exception in method: jakartaee.cdi.tutorial.store.payment.service.PaymentService.processPayment,
        execution time: 12ms, exception: Card number cannot be null

Real-World Benefits

Before: Manual Logging (Problems)

@ApplicationScoped
public class PaymentService {

    private static final Logger LOGGER = Logger.getLogger(PaymentService.class.getName());

    public boolean processPayment(PaymentDetails details) {
        LOGGER.info("Entering processPayment with: " + details);  // ← Clutter
        long start = System.currentTimeMillis();                  // ← Clutter
        try {
            if (!validatePaymentDetails(details)) {
                LOGGER.info("Validation failed");                  // ← Clutter
                return false;
            }
            boolean result = true;
            LOGGER.info("Exiting processPayment: " + result +      // ← Clutter
                       ", duration: " + (System.currentTimeMillis() - start) + "ms");

            return result;

        } catch (Exception e) {
            LOGGER.severe("Exception: " + e.getMessage());         // ← Clutter
            throw e;
        }
    }
}

Problems:

• 7 lines of logging code vs. 4 lines of business logic

• Easy to forget timing or exception logging

• Inconsistent log formats

• Hard to change logging strategy globally

After: Interceptor-Based Logging (Clean!)

@ApplicationScoped
@Logged  // <-- One annotation replaces all logging code!
public class PaymentService {
  // Pure business logic - zero logging clutter
    public boolean processPayment(PaymentDetails details) {
        if (!validatePaymentDetails(details)) {
            return false;
        }
        return true;
    }
}

Benefits:

• 100% business logic, 0% logging code

• Consistent logging automatically

• Change logging globally by modifying interceptor once

• Better testability (test business logic without logging)

CDI Proxies Limitation: Interceptors only work on CDI-managed beans invoked through proxies. Direct calls within the same class (e.g., this.method()) won’t trigger interceptors. Use @Inject to reference the bean if you need interception on internal calls.

Conclusion

CDI (Contexts and Dependency Injection) interceptors provide a powerful, clean way to implement automatic method logging in Jakarta EE (Enterprise Edition) and MicroProfile applications. By using interceptors:

• Separate concerns: Business logic stays clean

• Reduce boilerplate: One annotation replaces multiple lines of code

• Ensure consistency: All methods logged the same way

• Easy maintenance: Change logging in one place

• Better testability: Test business logic without logging noise

• Performance tracking: Automatic execution time measurement

Key Takeaways

1. Create binding annotation with @InterceptorBinding

2. Implement interceptor with @AroundInvoke method

3. Register in beans.xml: don’t forget this step!

4. Apply @Logged to classes or methods

5. Use final variables for thread safety

6. Always re-throw exceptions to preserve error flow

7. Remember CDI limitations: only injected beans, only public methods

Next Steps

To extend this pattern:

• Add performance alerting for slow methods

• Implement sensitive data masking

• Integrate with OpenTelemetry for distributed tracing

• Add request ID correlation across microservices

• Create audit interceptors for compliance tracking

• Build security interceptors for authorization

• Clean code through separation of concerns!

Related Resources

• Jakarta Interceptors Specification

• Jakarta CDI Specification

---

This article was originally published on Medium and is being shared here on dev.to to reach a broader developer audience.

If you prefer reading on Medium or would like to support my writing there, you can find the original article here:
👉 https://medium.com/@taruntelang/zero-logging-code-full-observability-production-ready-cdi-interceptors-91eda3388d7c

I regularly publish deep dives on Java architecture, microservices, observability, and system design. Feel free to follow along if those topics interest you.