fix: add None checks to run_java_checker (#1630)

Author: terriko

cve_bin_tool/version_scanner.py

@@ -234,13 +234,13 @@ def run_java_checker(self, filename: str) -> Iterator[ScanInfo]:
             if parent is None:
                 product = root.find(schema + "artifactId").text
                 version = root.find(schema + "version").text
-            if version is None:
+            if version is None and parent is not None:
                 version = parent.find(schema + "version").text
             # Check valid version identifier (i.e. starts with a digit)
             if not version[0].isdigit():
                 self.logger.debug(f"Invalid {version} detected in {filename}")
                 version = None
-            if product is None:
+            if product is None and parent is not None:
                 product = parent.find(schema + "artifactId").text
             if product is not None and version is not None:
                 product_info, file_path = self.find_java_vendor(product, version)