Fix SEPS fallback for empty connectionStringIndex (#214)

Treat blank connectionStringIndex as missing to enable default/single-entry fallback

Author: MouhsinElmajdouby

ojdbc-provider-common/src/main/java/oracle/jdbc/provider/util/WalletUtils.java

@@ -114,7 +114,8 @@ private WalletUtils() {}
    * </p>
    * <ol>
    *   <li>
-   *     <strong>If {@code connectionStringIndex} is {@code null}:</strong>
+   *     <strong>If {@code connectionStringIndex} is {@code null}, empty,
+   *     or blank:</strong>
    *     <ul>
    *       <li>
    *         The method first attempts to retrieve credentials using the default
@@ -183,6 +184,11 @@ private WalletUtils() {}
   public static Credentials getCredentials(
     byte[] walletBytes, char[] walletPassword, String connectionStringIndex) {
 
+    // treat blank as missing
+    if (connectionStringIndex != null && connectionStringIndex.trim().isEmpty()) {
+      connectionStringIndex = null;
+    }
+
     OracleWallet wallet = new OracleWallet();
     try {
       wallet.setWalletArray(walletBytes, walletPassword);