java properties xml 118 lines · 4 tabs

Custom Spring Boot starters

David Kumar Jan 2026

4 tabs

package com.example.starter.config;

import com.example.starter.properties.CustomProperties;
import com.example.starter.service.CustomService;
import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;

@AutoConfiguration
@ConditionalOnClass(CustomService.class)
@EnableConfigurationProperties(CustomProperties.class)
@ConditionalOnProperty(
    prefix = "custom.service",
    name = "enabled",
    havingValue = "true",
    matchIfMissing = true
)
public class CustomAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean
    public CustomService customService(CustomProperties properties) {
        return new CustomService(
            properties.getApiKey(),
            properties.getTimeout(),
            properties.getRetryAttempts()
        );
    }
}

package com.example.starter.properties;

import org.springframework.boot.context.properties.ConfigurationProperties;

import jakarta.validation.constraints.Min;
import jakarta.validation.constraints.NotBlank;

@ConfigurationProperties(prefix = "custom.service")
public class CustomProperties {

    /**
     * Enable or disable the custom service
     */
    private boolean enabled = true;

    /**
     * API key for authentication
     */
    @NotBlank(message = "API key is required")
    private String apiKey;

    /**
     * Request timeout in milliseconds
     */
    @Min(value = 1000, message = "Timeout must be at least 1000ms")
    private int timeout = 5000;

    /**
     * Number of retry attempts
     */
    @Min(value = 0, message = "Retry attempts must be non-negative")
    private int retryAttempts = 3;

    // Getters and Setters
    public boolean isEnabled() {
        return enabled;
    }

    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }

    public String getApiKey() {
        return apiKey;
    }

    public void setApiKey(String apiKey) {
        this.apiKey = apiKey;
    }

    public int getTimeout() {
        return timeout;
    }

    public void setTimeout(int timeout) {
        this.timeout = timeout;
    }

    public int getRetryAttempts() {
        return retryAttempts;
    }

    public void setRetryAttempts(int retryAttempts) {
        this.retryAttempts = retryAttempts;
    }
}

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.example.starter.config.CustomAutoConfiguration

<project>
    <groupId>com.example</groupId>
    <artifactId>custom-spring-boot-starter</artifactId>
    <version>1.0.0</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>
</project>

4 files · java, properties, xml Explain with highlit

Spring Boot starters provide autoconfiguration for libraries. I create custom starters to standardize configurations across microservices. Starters contain @Configuration classes with @ConditionalOnClass, @ConditionalOnProperty annotations. spring.factories registers auto-configuration classes. Starters follow naming convention: xxx-spring-boot-starter. Configuration properties use @ConfigurationProperties with metadata for IDE support. Starters encapsulate library setup, reducing boilerplate in applications. Order matters—@AutoConfigureAfter, @AutoConfigureBefore control sequence. Custom starters promote consistency, enable centralized updates, and simplify dependency management. They're essential for maintaining standards across large organizations with many Spring Boot applications.

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