squid:S2974 - Classes without public constructors should be final

src/main/java/com/smartsheet/utils/ConfigHolder.java

@@ -20,7 +20,7 @@
  * A holder of specific configuration properties for the current application.
  * Any such properties are injected into this holder.
  */
-public class ConfigHolder {
+public final class ConfigHolder {
 
     private static final ConfigHolder singleton = new ConfigHolder();
 

src/main/java/com/smartsheet/utils/ErrorHandler.java

@@ -19,7 +19,7 @@
 /**
  * An application-level error handler.
  */
-public class ErrorHandler {
+public final class ErrorHandler {
 
     private ErrorHandler() {
         // private constructor because this is a singleton helper class, not intended to be instantiated

src/main/java/com/smartsheet/utils/FileUtils.java

@@ -29,7 +29,7 @@
 /**
  * Utilities for file operations.
  */
-public class FileUtils {
+public final class FileUtils {
 
     private static final int ZIP_BUFFER_SIZE = 64*1024; // 64K
 

src/main/java/com/smartsheet/utils/HttpUtils.java

@@ -42,7 +42,7 @@
 /**
  * Utilities for HTTP operations.
  */
-public class HttpUtils {
+public final class HttpUtils {
 
     private static final String CHARSET = "UTF-8";
     private static final String ACCEPT_JSON_HEADER = "application/json; charset=" + CHARSET.toLowerCase();

src/main/java/com/smartsheet/utils/ProgressWatcher.java

@@ -29,7 +29,7 @@
  * A Progress Watcher which receives status and error notifications, publishing
  * them to the console.
  */
-public class ProgressWatcher {
+public final class ProgressWatcher {
 
     private static final String SMARTSHEET_BACKUP_ERROR_LOG_PREFIX = "smartsheet-backup-error-log_";
     private static final String SMARTSHEET_BACKUP_ERROR_LOG_EXTENSION = ".log";