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Java Development Standards

Runtime vs Syntax Compatibility

  • Runtime Environment: Java 21 (production)
  • Syntax Requirement: Java 11 compatible (core modules)
  • CLI Tools Exception: Java 21 features allowed in tools/dotcms-cli only

✅ Use Java 11 Syntax in Core Modules

// Java 11 compatible patterns
var users = userAPI.findActiveUsers();
var contentTypes = contentTypeAPI.findAll();

// Java 11 compatible Optional and Stream operations
Optional<String> value = getValue();
String result = value.orElse("default");

List<String> names = users.stream()
    .map(User::getName)
    .filter(Objects::nonNull)
    .collect(Collectors.toList());

// Traditional string concatenation or String.format()
String query = "SELECT c.identifier, c.title FROM contentlet c " +
               "WHERE c.structure_inode = ?";

// Traditional switch statements
String status;
switch (contentlet.getBaseType()) {
    case CONTENT:
        status = "Content";
        break;
    case HTMLPAGE:
        status = "Page";
        break;
    default:
        status = "Unknown";
}

✅ Java 21 Syntax (CLI/Tools Modules Only)

// ONLY in tools/dotcms-cli and test modules
var query = """
    SELECT c.identifier, c.title FROM contentlet c 
    WHERE c.structure_inode = ?
    """;

var status = switch (contentlet.getBaseType()) {
    case CONTENT -> "Content";
    case HTMLPAGE -> "Page";
    default -> "Unknown";
};

public record UserInfo(String id, String email, String name) {}

Core Development Patterns

API Locator Pattern (Required)

// Service access - ALWAYS use APILocator
UserAPI userAPI = APILocator.getUserAPI();
ContentletAPI contentletAPI = APILocator.getContentletAPI();

// Web services
UserWebAPI userWebAPI = WebAPILocator.getUserWebAPI();

// ❌ NEVER instantiate services directly
// UserAPIImpl userAPI = new UserAPIImpl();

Configuration Management (Required)

Security: All configuration must follow Security Principles

import com.dotmarketing.util.Config;

// Hierarchical naming for new properties
boolean enabled = Config.getBooleanProperty("experiments.enabled", false);
String url = Config.getStringProperty("experiments.auto-js-injection.url", "");

// Environment variables automatically get DOT_ prefix
// experiments.enabled → DOT_EXPERIMENTS_ENABLED

Property Resolution Order

  1. Environment variables with DOT_ prefix (e.g., DOT_EXPERIMENTS_ENABLED)
  2. System table for both transformed and original names
  3. Properties files for both transformed and original names

New Property Naming Convention

# Use hierarchical domain-driven naming (RECOMMENDED)
experiments.enabled=true
experiments.auto-js-injection.enabled=true
experiments.auto-js-injection.url=https://example.com/script.js
experiments.auto-js-injection.max-retries=3

health.checks.database.timeout-seconds=30
health.monitoring.include-system-details=true

Logging Standards (Required)

import com.dotmarketing.util.Logger;

Logger.info(this, "Operation completed successfully");
Logger.error(this, "Operation failed: " + error.getMessage(), error);

// ❌ NEVER use: System.out.println(), printStackTrace(), System.err.println()

Immutable Objects (Critical Pattern)

@Value.Immutable
@JsonSerialize(as = ImmutableMyEntity.class)
@JsonDeserialize(as = ImmutableMyEntity.class)
public abstract class MyEntity {
    public abstract String name();
    public abstract Optional<String> description();
    
    @Value.Default
    public boolean enabled() { return true; }
    
    public static Builder builder() { return ImmutableMyEntity.builder(); }
}

// Usage: MyEntity.builder().name("test").description("desc").build()
// IMPORTANT: Run ./mvnw compile after creating @Value.Immutable classes

Exception Handling (dotCMS Hierarchy)

try {
    riskyOperation();
} catch (SQLException e) {
    Logger.error(this, "Database operation failed: " + e.getMessage(), e);
    throw new DotDataException("Failed to process request", e);
} catch (SecurityException e) {
    throw new DotSecurityException("Access denied", e);
}

// Exception types: DotDataException, DotSecurityException, DotRuntimeException, DotStateException

Utility Methods (Null-Safe Patterns)

import com.dotmarketing.util.UtilMethods;

// ALWAYS use UtilMethods.isSet() for null checking
if (UtilMethods.isSet(myString)) {  // checks null, empty, and "null" string
    processString(myString);
}

// Collections
List<String> list = CollectionsUtils.list("item1", "item2");
Map<String, Object> map = CollectionsUtils.map("key1", "value1", "key2", "value2");

// Safe supplier pattern (avoids NullPointerException)
String value = UtilMethods.isSet(() -> complex.getObject().getValue()) 
    ? complex.getObject().getValue() 
    : "default";

Database Access Patterns

import com.dotmarketing.common.db.DotConnect;

// Query with parameters
DotConnect dotConnect = new DotConnect();
List<Map<String, Object>> results = dotConnect
    .setSQL("SELECT * FROM my_table WHERE column1 = ? AND column2 = ?")
    .addParam("value1")
    .addParam("value2")
    .loadResults();

// Use with LocalTransaction for atomic operations
LocalTransaction.wrapReturn(() -> {
    return dotConnect.setSQL("UPDATE my_table SET column1 = ?")
        .addParam("newValue")
        .executeUpdate();
});

CDI Patterns (For New Components)

@ApplicationScoped
public class MyService {
    private final JobQueueManagerAPI jobQueueManagerAPI;
    
    // Default constructor required for CDI proxy
    public MyService() {
        this.jobQueueManagerAPI = null;
    }
    
    @Inject
    public MyService(JobQueueManagerAPI jobQueueManagerAPI) {
        this.jobQueueManagerAPI = jobQueueManagerAPI;
    }
}

// Safe CDI bean access
Optional<MyService> service = CDIUtils.getBean(MyService.class);
MyService service = CDIUtils.getBeanThrows(MyService.class);

Build Integration Requirements

After Code Changes

  • Immutable classes: Run ./mvnw compile after @Value.Immutable changes
  • Fast iteration: ./mvnw install -pl :dotcms-core -DskipTests
  • Docker updates: Run ./mvnw clean install (without -Ddocker.skip)

Critical Docker Build Workflow

Docker image updates only happen when building WITHOUT -Ddocker.skip:

# Fast development cycle (no Docker image update)
./mvnw install -pl :dotcms-core -DskipTests -Ddocker.skip

# When ready to test in Docker (REQUIRED for new servlets/endpoints):
./mvnw -DskipTests clean install  # Updates Docker image
./mvnw -pl :dotcms-core -Pdocker-start -Dtomcat.port=8080

Legacy Patterns to Avoid in New Code

See: Progressive Enhancement for safe improvement strategies

// ❌ Avoid in new development
@Deprecated public class MyPortletAction extends PortletAction {}
@Deprecated public class MyAjax extends WfBaseAction {}
System.out.println("message");
System.getProperty("property");
StructureAPI structureAPI = APILocator.getStructureAPI();

// ✅ Use modern alternatives
@Path("/v1/resource") public class MyResource {}
Logger.info(this, "message");
Config.getStringProperty("property", "default");
ContentTypeAPI contentTypeAPI = APILocator.getContentTypeAPI();

// ✅ For class metadata analysis, prefer Jandex over reflection
List<Class<?>> annotatedClasses = JandexClassMetadataScanner.findClassesWithAnnotation(
    MyAnnotation.class, "com.dotcms.mypackage");
// See: docs/backend/JANDEX_METADATA_SCANNING.md