Update src/main/java/org/spdx/utility/compare/LicenseCompareHelper.java

Co-authored-by: Gary O'Neall <gary@sourceauditor.com>
Signed-off-by: Arthit Suriyawongkul <arthit@gmail.com>

Author: bact

src/main/java/org/spdx/utility/compare/LicenseCompareHelper.java

@@ -232,7 +232,7 @@ public static String locateOriginalText(String fullLicenseText, int startToken,
 	 * @return {@code true} if the text contains a single token,
 	 *         {@code false} otherwise.
 	 */
-	public static boolean isSingleTokenString(String text) {
+	public static boolean isSingleTokenString(@Nullable String text) {
 		if (text == null) {
 			return false;
 		}