In application development, performance is not just a feature; it is a fundamental requirement.

Slow applications lead to poor user experiences, reduced customer satisfaction, and ultimately, a negative impact on business goals.

For developers working within the Java ecosystem, achieving optimal performance often involves navigating complex configurations and fine-tuning interactions between different layers of an application.

This is particularly true when dealing with database operations and dependency management.

This guide explores practical strategies for performance tuning using two powerful tools: Ebean ORM and Avaje Inject.

Ebean is a high-performance Object-Relational Mapping (ORM) framework for Java that simplifies database access, while Avaje Inject is a lightweight dependency injection library designed for speed and simplicity.

By leveraging the specific features of these tools, developers can significantly enhance application responsiveness, reduce latency, and build more scalable systems.

We will cover key techniques that address common performance bottlenecks, from optimizing database queries to streamlining object creation.

Understanding Performance Bottlenecks in Java Applications

Before improving performance, it’s crucial to identify where the slowdowns occur. In typical enterprise applications, bottlenecks often appear in several key areas.

Database Interactions

• N+1 Query Problem: This common issue arises when an ORM executes one query to fetch a list of parent entities and then separate queries for each child entity. The result is a cascade of database calls that dramatically increases latency.
• Excessive Data Fetching: Retrieving more columns or rows than necessary consumes memory and network bandwidth. Fetching large, unoptimized data graphs can bring an application to a crawl.
• Inefficient Queries: Poorly constructed queries, missing indexes, or overuse of complex joins can strain the database, leading to slow response times.

Application Layer Overhead

• Dependency Injection Complexity: While dependency injection (DI) is a cornerstone of modern application design, traditional reflection-based DI frameworks can introduce startup overhead. Scanning the classpath and resolving dependencies at runtime can be time-consuming, especially in large applications.
• Object Instantiation: Frequent creation of heavy objects can put pressure on the garbage collector, causing pauses and unpredictable performance dips.

Optimizing Queries with Ebean ORM

Ebean ORM provides a rich set of features specifically designed to tackle common database performance issues. Effective performance tuning with Ebean starts with writing efficient queries.

Solving the N+1 Problem

Ebean offers several ways to eagerly fetch related entities, effectively solving the N+1 query problem with a single, optimized query.

• fetch() Method: Use the fetch() method to specify which related entities should be included in the initial query. This tells Ebean to generate a SQL join to retrieve all necessary data at once.
  // Fetches customers and their associated addresses in a single query
  List<Customer> customers = Ebean.find(Customer.class)
      .fetch(“billingAddress”)
      .findList();
• Fetch Groups: For more complex scenarios, Fetch Groups allow you to define reusable fetching strategies. This promotes consistency and simplifies query construction.

Partial Object Queries

To avoid fetching unnecessary data, Ebean allows you to select only the columns you need.

• select() and fetch() combination: Specify the properties for the root entity with select() and the properties for related entities within fetch().
  // Fetches only the customer’s name and the city of their billing address
  List<Customer> customers = Ebean.find(Customer.class)
      .select(“name”)
      .fetch(“billingAddress”, “city”)
      .findList();

Leveraging Ebean’s Advanced Features

Beyond basic query optimization, Ebean includes advanced capabilities that provide granular control over performance.

Query Plan Caching

Ebean automatically caches the SQL generated from ORM queries. When the same query structure is executed again, Ebean reuses the cached SQL, skipping the generation phase and reducing overhead. This process is automatic and requires no special configuration.

L2 Caching for Entities

Ebean’s L2 cache stores entity data in a server-side cache, which can dramatically reduce database load.

• Enabling L2 Caching: You can enable caching on a per-entity basis using the @Cache annotation. This is most effective for read-mostly data, such as reference tables (e.g., countries, statuses).
  @Cache(nearCache = true)
  @Entity
  public class Country {
      // … properties
  }
• Query Caching: You can also cache the results of specific queries. This is useful for queries that are executed frequently with the same parameters.
  List<Customer> customers = Ebean.find(Customer.class)
      .setUseQueryCache(true)
      .where().eq(“status”, “ACTIVE”)
      .findList();

Accelerating Startup with Avaje Inject

Avaje Inject is a compile-time dependency injection framework. Unlike reflection-based DI frameworks that scan the classpath at runtime, Avaje Inject generates all dependency wiring during compilation. This approach offers significant performance benefits.

Eliminating Reflection

The core advantage of Avaje Inject is its avoidance of runtime reflection.

• Compile-Time Generation: By generating Java source code for dependency injection, Avaje Inject creates a highly optimized, reflection-free context.
• Faster Startup: Applications using Avaje Inject experience much faster startup times because the dependency graph is already resolved before the application even runs. This is especially beneficial for microservices and serverless functions where startup latency is critical.

Simple and Efficient Injection

Avaje Inject uses standard Jakarta annotations like @Singleton and @Inject, making it easy to adopt.

• @Singleton: Marks a class as a singleton bean.
• @Factory: Marks a class with methods that produce beans (similar to Spring’s @Configuration).
• @Inject: Injects a dependency.

@Singleton

public class OrderService {

 

   private final CustomerRepository customerRepo;

 

   @Inject

   public OrderService(CustomerRepository customerRepo) {

       this.customerRepo = customerRepo;

   }

 

   // … service methods

}

Integrating Ebean ORM with Avaje Inject

Combining Ebean ORM with Avaje Inject creates a highly optimized stack. Avaje Inject can manage the lifecycle of your Ebean Database instance and inject it into your services and repositories.

Configuring the Ebean Database Bean

You can create a factory class to configure and provide the Ebean Database instance as a bean.

@Factory

public class AppConfig {

 

   @Bean

   public Database createEbeanDatabase() {

       DatabaseConfig config = new DatabaseConfig();

       // … configure data source, etc.

       return DatabaseFactory.create(config);

   }

}

Avaje Inject will discover this factory and make the Database instance available for injection throughout your application, ensuring a single, efficiently managed instance.

Injecting the Database Instance

Once configured, you can inject the Database instance directly into your repositories or DAOs.

@Singleton

public class CustomerRepository {

 

   private final Database database;

 

   @Inject

   public CustomerRepository(Database database) {

       this.database = database;

   }

 

   public Optional<Customer> findById(long id) {

       return database.find(Customer.class).setId(id).findOneOrEmpty();

   }

}

This integration combines Ebean’s powerful database performance tuning features with Avaje Inject’s lightning-fast dependency injection, creating a robust foundation for high-performance applications.

Path to Enhanced Performance

Achieving optimal performance is a continuous process of measurement, analysis, and refinement.

For Java developers, tools like Ebean ORM and Avaje Inject provide powerful mechanisms to address common bottlenecks at both the database and application layers.

By mastering query optimization techniques in Ebean and embracing the compile-time efficiency of Avaje Inject, you can build applications that are not only fast and responsive but also scalable and maintainable.

Start by profiling your application to identify the most significant pain points.

Apply the strategies discussed here, such as eager fetching and partial object queries, and consider leveraging compile-time dependency injection to reduce startup overhead. Every optimization brings you closer to delivering an exceptional user experience.