Gradle automatic property expansion to pass parameters into Spring Boot not working in Eclipse

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1

The application runs as expected when running as bootRun task in Eclipse IDE, but right clicking on project → Run As → Spring Boot App doesn’t replace the value of the property in the following prototype.

  1. build.gradle file
import org.apache.tools.ant.filters.ReplaceTokens

plugins {
	id 'org.springframework.boot' version '2.6.1'
	id 'io.spring.dependency-management' version '1.0.11.RELEASE'
	id 'java'
	id 'eclipse'
}

group = 'com.sample.auto.expansion'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {
	mavenCentral()
}

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

test {
	useJUnitPlatform()
}

// enable auto property expansion for passing gradle property to spring boot
// https://www.baeldung.com/spring-boot-auto-property-expansion
processResources {
    duplicatesStrategy = 'include'
    with copySpec {
        from 'src/main/resources'
        include '**/application*.properties'
        include '**/application*.yaml'
        include '**/application*.yml'
        project.properties.findAll().each {
            prop ->
                if (prop.key != null) {
                    filter(ReplaceTokens, tokens: [(prop.key): prop.value.toString()])
                    filter(ReplaceTokens, tokens: [('project.' + prop.key): prop.value.toString()])
                }
        }
    }
}
  1. gradle.properties
expansion.property=Hello Expansion Property!
  1. application.properties
com.test.value=@expansion.property@
  1. DemoApplication.java
package com.sample.auto.expansion.demo;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication implements CommandLineRunner {
	@Value("${com.test.value}")
	String expansionProperty;
	
	public static void main(String[] args) {
		SpringApplication.run(DemoApplication.class, args);
	}

	@Override
	public void run(String... args) throws Exception {
		 System.out.println(expansionProperty);
	}

}

The bootRun task results in expected output:

Hello Expansion Property!

BUILD SUCCESSFUL in 1s
4 actionable tasks: 4 executed

Running it as Spring Boot App in Eclipse results literal output without the value being replaced.

2021-12-04 21:49:35.598  INFO 27293 --- [           main] c.s.auto.expansion.demo.DemoApplication   : Started DemoApplication in 1.097 seconds (JVM running for 2.105)
@expansion.property@

I have also posted this issue in stackoverflow at java - How to pass gradle properties into Spring Boot and debug in Eclipse? - Stack Overflow

2

Why do you expect that property expansion is going to work when you specifically run the application in a way that bypasses the tool doing the property expansion?

3

Thanks for your prompt response. I currently have a workaround using Spring profile to pass hard-coded values running/debugging the app locally in Eclipse, but the intent here is to see how the great minds are overcoming this problem.