private void checkSerialVersionUID(JCClassDecl tree, ClassSymbol c) {

            // check for presence of serialVersionUID
            Scope.Entry e = c.members().lookup(names.serialVersionUID);
            while (e.scope != null && e.sym.kind != VAR) e = e.next();
            if (e.scope == null) {
                log.warning(tree.pos(), "missing.SVUID", c);
                return;
            }

            // check that it is static final
            VarSymbol svuid = (VarSymbol)e.sym;
            if ((svuid.flags() & (STATIC | FINAL)) !=
                (STATIC | FINAL))
                log.warning(TreeInfo.diagnosticPositionFor(svuid, tree), "improper.SVUID", c);

            // check that it is long
            else if (svuid.type.tag != TypeTags.LONG)
                log.warning(TreeInfo.diagnosticPositionFor(svuid, tree), "long.SVUID", c);

            // check constant
            else if (svuid.getConstValue() == null)
                log.warning(TreeInfo.diagnosticPositionFor(svuid, tree), "constant.SVUID", c);
        }