SpringBoot: EL1003E property values casting

Question

I have a Spring Boot config file with this values:

@Value("#{new Integer('${db.pool.size}')}")
private Integer dbPoolSize;

@Value("#{new Integer('${db.minimum.idle}')}")
private Integer dbMinimumIdle;

But when I start the application I got this error:

Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1003E: A problem occurred whilst attempting to construct an object of type 'Integer' using arguments '(java.lang.String)'
    at org.springframework.expression.spel.ast.ConstructorReference.createNewInstance(ConstructorReference.java:168) ~[spring-expression-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.expression.spel.ast.ConstructorReference.getValueInternal(ConstructorReference.java:98) ~[spring-expression-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:120) ~[spring-expression-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:242) ~[spring-expression-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.context.expression.StandardBeanExpressionResolver.evaluate(StandardBeanExpressionResolver.java:161) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    ... 42 common frames omitted

Answer 1

Imagine you have the following application.properties:

db.minimum.idle=12
db.pool.size=10

Then you should just do something like:

@Value("${db.pool.size}")
private Integer dbPoolSize;

@Value("${db.minimum.idle}")
private Integer dbMinimumIdle;

You do not have to create a new integer, that is automacally done by spring