Solve issue 2329 - StringIndexOutOfBoundsException on empty collection in encodeObject method. (#2330)

Author: mzitnik

jdbc-v2/src/main/java/com/clickhouse/jdbc/PreparedStatementImpl.java

@@ -590,7 +590,9 @@ private static String encodeObject(Object x) throws SQLException {
                 for (Object item : (Collection<?>) x) {
                     listString.append(encodeObject(item)).append(", ");
                 }
-                listString.delete(listString.length() - 2, listString.length());
+                if (listString.length() > 1) {
+                    listString.delete(listString.length() - 2, listString.length());
+                }
                 listString.append("]");
 
                 return listString.toString();

jdbc-v2/src/test/java/com/clickhouse/jdbc/PreparedStatementTest.java

@@ -13,10 +13,7 @@
 import java.sql.ResultSetMetaData;
 import java.sql.Statement;
 import java.sql.Types;
-import java.util.Arrays;
-import java.util.GregorianCalendar;
-import java.util.TimeZone;
-import java.util.UUID;
+import java.util.*;
 
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertFalse;
@@ -583,7 +580,7 @@ void testClearParameters() throws Exception {
     }
 
     @Test(groups = {"integration"})
-    void testWriteCollection() throws Exception {
+    void testWriteUUID() throws Exception {
         String sql = "insert into `test_issue_2327` (`id`, `uuid`) values (?, ?)";
         try (Connection conn = getJdbcConnection();
              PreparedStatementImpl ps = (PreparedStatementImpl) conn.prepareStatement(sql)) {
@@ -604,4 +601,31 @@ void testWriteCollection() throws Exception {
         }
 
     }
+
+    @Test(groups = {"integration"})
+    void testWriteCollection() throws Exception {
+        String sql = "insert into `test_issue_2329` (`id`, `name`, `age`, `arr`) values (?, ?, ?, ?)";
+        try (Connection conn = getJdbcConnection();
+             PreparedStatementImpl ps = (PreparedStatementImpl) conn.prepareStatement(sql)) {
+
+            try (Statement stmt = conn.createStatement()) {
+                stmt.execute("CREATE TABLE IF NOT EXISTS `test_issue_2329` (`id` Nullable(String), `name` Nullable(String), `age` Int32, `arr` Array(String)) ENGINE Memory;");
+            }
+
+            Assert.assertEquals(ps.getParametersCount(), 4);
+            Collection<String> arr = new ArrayList<String>();
+            ps.setString(1, "testId01");
+            ps.setString(2, "testName");
+            ps.setInt(3, 18);
+            ps.setObject(4, arr);
+            ps.execute();
+
+            try (Statement stmt = conn.createStatement()) {
+                ResultSet rs = stmt.executeQuery("SELECT count(*) FROM `test_issue_2329`");
+                Assert.assertTrue(rs.next());
+                Assert.assertEquals(rs.getInt(1), 1);
+            }
+        }
+
+    }
 }