This rule is defined by the following XPath expression:
//FieldDeclaration [@Final='true' and @Static='false'] [not (../../../../ClassOrInterfaceDeclaration[@Interface='true'])] /VariableDeclarator/VariableInitializer/Expression /PrimaryExpression/PrimaryPrefix/Literal
Example:
public class Foo { public final int BAR = 42; // this could be static and save some space }