Different property resolution if property value is empty

[renetrefft]

Affects: 5.1.6 / 4.3.23 + Spring Tools 4.2.0

@Component
public class PropertiesTest {

	@Value("${key}")
	String property;

        @Value("${key}")
	String[] propertyArr;
	
}

If a property key is defined without a value in application.properties (i.e. key=) the variable property is initialized with an empty String and propertyArr with an empty String array.

If key is defined without a value in a 'Spring Boot App' Eclipse launch configuration instead ("Override Properties" feature) the start of the application fails:

java.lang.IllegalArgumentException: Could not resolve placeholder 'key' in value "${key}"

Spring should always resolve a property with an empty value as an empty String / String array.

[sbrannen]

It sounds to me like this is an issue with Spring Tools 4.

In light of that, I recommend you open an issue in the Spring Tools issue tracker, and I will close this issue here.

/cc @martinlippert

[martinlippert]

looks like this is indeed an issue with the boot launch support in the Spring Tools, not setting empty values from the custom properties of the launch in the same way than empty values in the properties file. Filed an issue here:

spring-projects/spring-tools#275

[sbrannen]

Thanks, @martinlippert

[martinlippert]

Quick update: this is fixed now, will be released as part of the Spring Tools 4.2.1 release, coming later this week.