Error message updates

contentstack/src/main/java/com/contentstack/sdk/Contentstack.java

@@ -27,7 +27,7 @@ public class Contentstack {
     private static Contentstack instance;
 
     private Contentstack(Context context) {
-        throw new IllegalStateException("Private constructor not allowed");
+        throw new IllegalStateException(ErrorMessages.PRIVATE_CONSTRUCTOR_NOT_ALLOWED);
     }
 
     /**

contentstack/src/main/java/com/contentstack/sdk/ErrorMessages.java

@@ -0,0 +1,33 @@
+package com.contentstack.sdk;
+
+/**
+ * Contains all error messages used across the SDK.
+ * Centralizing messages here makes it easier to maintain and update them.
+ */
+public final class ErrorMessages {
+    private ErrorMessages() {
+        throw new IllegalStateException("Utility class - do not instantiate");
+    }
+
+    // Constructor related errors
+    public static final String PRIVATE_CONSTRUCTOR_NOT_ALLOWED = 
+        "This class does not support private constructors. Use a public constructor to create an instance.";
+    public static final String UTILITY_CLASS_INSTANTIATION = 
+        "This is a utility class and cannot be instantiated";
+    public static final String NODE_TO_HTML_INSTANTIATION = 
+        "Failed to create an instance of NodeToHTML, you can directly access the methods of this class";
+
+    // Input validation errors
+    public static final String NULL_OR_EMPTY_INPUT = 
+        "The input value cannot be null or empty. Provide a valid string to continue.";
+
+    // Network and parsing errors
+    public static final String ENCODING_ERROR = 
+        "The system encountered an encoding issue while processing your request. Try again or contact support.";
+    public static final String JSON_PARSING_ERROR = 
+        "We couldn't process the response due to a data formatting issue. Try again or contact support if the problem persists.";
+
+    // Cache related errors
+    public static final String CACHE_INITIALIZATION_ERROR = 
+        "Failed to initialize cache. The application will continue without caching.";
+}

contentstack/src/main/java/com/contentstack/sdk/InvalidInputException.java

@@ -13,7 +13,7 @@
  * <code>
  * public void processInput(String input) throws InvalidInputException {
  * if (input == null || input.isEmpty()) {
- * throw new InvalidInputException("Input cannot be null or empty");
+ * throw new InvalidInputException(ErrorMessages.NULL_OR_EMPTY_INPUT);
  * }
  * // Process the input here
  * }

contentstack/src/main/java/com/contentstack/sdk/JSONUTF8Request.java

@@ -24,9 +24,9 @@ protected Response<JSONObject> parseNetworkResponse(NetworkResponse response) {
             String jsonString = new String(response.data, "UTF-8");
             return Response.success(new JSONObject(jsonString), HttpHeaderParser.parseCacheHeaders(response));
         } catch (UnsupportedEncodingException e) {
-            return Response.error(new ParseError(e));
+            return Response.error(new ParseError(new UnsupportedEncodingException(ErrorMessages.ENCODING_ERROR)));
         } catch (JSONException je) {
-            return Response.error(new ParseError(je));
+            return Response.error(new ParseError(new JSONException(ErrorMessages.JSON_PARSING_ERROR)));
         }
     }
 

contentstack/src/main/java/com/contentstack/sdk/NodeToHTML.java

@@ -4,7 +4,7 @@
 
 public class NodeToHTML {
     private NodeToHTML() {
-        throw new IllegalStateException("Could not create instance of NodeToHTML");
+        throw new IllegalStateException(ErrorMessages.NODE_TO_HTML_INSTANTIATION);
     }
     public static String textNodeToHTML(JSONObject nodeText, Option renderOption) {
         String text = nodeText.optString("text");