Getting warnings when I am starting my Springboot application : WARNING: An illegal reflective access operation has occurred

Here is the warning :

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.vmplugin.v7.Java7$1 
         (file:/C:/Users/.m2/repository/org/codehaus/groovy/groovy/2.5.6/groovy-2.5.6.jar) to 
         constructor java.lang.invoke.MethodHandles$Lookup(java.lang.Class,int)
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.vmplugin.v7.Java7$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

What may be causing this and how to get rid of them?