This rule is defined by the following XPath expression:
//ClassOrInterfaceBody[count(ClassOrInterfaceBodyDeclaration/ConstructorDeclaration)=1] /ClassOrInterfaceBodyDeclaration/ConstructorDeclaration [@Public='true'] [not(FormalParameters/*)] [not(BlockStatement)] [not(NameList)] [count(ExplicitConstructorInvocation/Arguments/ArgumentList/Expression)=0]
Example:
public class Foo { public Foo() {} }