JDBC Client Driver Logger not being configured correctly (#967)

## Description
JDBC client driver is present in a different namespace than the general
codebase and due to this when we configure loglevel we only configure
the root logger in the `com.databricks.jdbc` chain but the Driver falls
in the `com.databricks.client.jdbc` chain and hence was not configured
properly

## Issue
#965

## Testing
Manual testing to view logs in file and console settings

`NO_CHANGELOG=true`

Author: jprakash-db

src/main/java/com/databricks/jdbc/common/util/LoggingUtil.java

@@ -19,8 +19,8 @@ public static void setupLogger(String logDir, int logFileSizeMB, int logFileCoun
       throws IOException {
     if (LOGGER instanceof JulLogger && System.getProperty(JAVA_UTIL_LOGGING_CONFIG_FILE) == null) {
       // Only configure JUL logger if it's not already configured via external properties file
-      LOGGER.info("Setting up JUL logger");
       JulLogger.initLogger(toJulLevel(level), logDir, logFileSizeMB * 1024 * 1024, logFileCount);
+      LOGGER.info("Setting up JUL logger");
     }
   }
 

src/main/java/com/databricks/jdbc/log/JulLogger.java

@@ -7,6 +7,7 @@
 import java.util.Set;
 import java.util.logging.*;
 import java.util.stream.Stream;
+import org.apache.commons.lang3.StringUtils;
 
 /**
  * The {@code JulLogger} class provides an implementation of the {@link JdbcLogger} interface using
@@ -27,10 +28,14 @@ public class JulLogger implements JdbcLogger {
 
   private static final String DEFAULT_PACKAGE_PREFIX = "com.databricks.jdbc";
 
+  private static final String DEFAULT_DRIVER_PACKAGE_PREFIX = "com.databricks.client.jdbc";
+
   public static final String STDOUT = "STDOUT";
 
   public static final String PARENT_CLASS_PREFIX = getPackagePrefix();
 
+  public static final String DRIVER_CLASS_PREFIX = getDriverPackagePrefix();
+
   public static final String DATABRICKS_LOG_FILE = "databricks_jdbc.log";
 
   public static final String JAVA_UTIL_LOGGING_CONFIG_FILE = "java.util.logging.config.file";
@@ -130,10 +135,15 @@ public static synchronized void initLogger(
       // java.util.logging uses hierarchical loggers, so we just need to set the log level on the
       // parent package logger
       Logger jdbcJulLogger = Logger.getLogger(PARENT_CLASS_PREFIX);
-
       jdbcJulLogger.setLevel(level);
       jdbcJulLogger.setUseParentHandlers(false);
 
+      // Jdbc client driver is present in a different namespace and hence need to configure its
+      // logger separately
+      Logger jdbcDriverJulLogger = Logger.getLogger(DRIVER_CLASS_PREFIX);
+      jdbcDriverJulLogger.setLevel(level);
+      jdbcDriverJulLogger.setUseParentHandlers(false);
+
       String logPattern = getLogPattern(logDir);
       Handler handler;
       if (logPattern.equalsIgnoreCase(STDOUT)) {
@@ -152,6 +162,7 @@ public void publish(LogRecord record) {
       handler.setLevel(level);
       handler.setFormatter(new Slf4jFormatter());
       jdbcJulLogger.addHandler(handler);
+      jdbcDriverJulLogger.addHandler(handler);
     }
   }
 
@@ -225,6 +236,14 @@ private static String getPackagePrefix() {
     return DEFAULT_PACKAGE_PREFIX;
   }
 
+  private static String getDriverPackagePrefix() {
+    String prefix = System.getenv("JDBC_DRIVER_PACKAGE_PREFIX");
+    if (StringUtils.isNotEmpty(prefix)) {
+      return prefix;
+    }
+    return DEFAULT_DRIVER_PACKAGE_PREFIX;
+  }
+
   private String slf4jToJavaFormat(String format) {
     if (format == null) {
       return null;