In Spring integration testing, configuration values are usually fixed through property files or @TestPropertySource. However, some tests require values that are only known at runtime, such as dynamically allocated ports or values produced by external resources.

@DynamicPropertySource addresses this limitation by allowing tests to register properties programmatically before the application context is refreshed. This ensures that beans depending on those properties are initialized with the correct values.

Java source and doc

Definition of DynamicPropertySource

 package org.springframework.test.context;
 @Target(ElementType.METHOD)
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 public @interface DynamicPropertySource {
 }

Example

The following example demonstrates how a dynamically generated value is registered as a Spring property and injected into a bean during test execution.

package com.logicbig.example;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.test.context.DynamicPropertyRegistry;
import org.springframework.test.context.DynamicPropertySource;
import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;

@SpringJUnitConfig
public class DynamicPropertySourceTest {

     @Autowired
     String appMode;

    @DynamicPropertySource
    static void registerProperties(DynamicPropertyRegistry registry) {
        registry.add("app.mode", () -> "runtimeValue");
    }

    @Test
    void myTest() {
        Assertions.assertEquals("runtimeValue", appMode);
    }

    @Configuration
    static class TestConfig {
        @Bean
        String appMode(Environment environment) {
            return environment.getProperty("app.mode");
        }
    }
}

Output

$ mvn test
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------< com.logicbig.example:dynamic-property-source >------------
[INFO] Building dynamic-property-source 1.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- resources:3.3.1:resources (default-resources) @ dynamic-property-source ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\spring-core-testing\dynamic-property-source\src\main\resources
[INFO] 
[INFO] --- compiler:3.11.0:compile (default-compile) @ dynamic-property-source ---
[INFO] No sources to compile
[INFO] 
[INFO] --- resources:3.3.1:testResources (default-testResources) @ dynamic-property-source ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\spring-core-testing\dynamic-property-source\src\test\resources
[INFO] 
[INFO] --- compiler:3.11.0:testCompile (default-testCompile) @ dynamic-property-source ---
[INFO] Changes detected - recompiling the module! :input tree
[WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent!
[INFO] Compiling 1 source file with javac [debug target 21] to target\test-classes
[INFO] 
[INFO] --- surefire:3.2.5:test (default-test) @ dynamic-property-source ---
[INFO] Using auto detected provider org.apache.maven.surefire.junitplatform.JUnitPlatformProvider
[WARNING] file.encoding cannot be set as system property, use <argLine>-Dfile.encoding=...</argLine> instead
[INFO] 
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.logicbig.example.DynamicPropertySourceTest
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.601 s -- in com.logicbig.example.DynamicPropertySourceTest
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  6.598 s
[INFO] Finished at: 2026-02-09T10:25:57+08:00
[INFO] ------------------------------------------------------------------------

Conclusion

The output confirms that the property value was resolved from the dynamically registered supplier instead of a static configuration source. This demonstrates how @DynamicPropertySource enables reliable testing when configuration values must be computed or discovered at runtime.

Example Project

Dependencies and Technologies Used:

• spring-context 7.0.4 (Spring Context)
   Version Compatibility: 5.2.5.RELEASE - 7.0.4Version List
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  Version compatibilities of spring-context with this example:

  • 5.2.5.RELEASE
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  Compatible Java Version: 17+
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  Versions in green have been tested.

• spring-test 7.0.4 (Spring TestContext Framework)
  
• junit-jupiter-engine 6.0.2 (Module "junit-jupiter-engine" of JUnit)
  
• JDK 25
• Maven 3.9.11