diff --git a/src/main/java/fr/unistra/sil/erp/back/Config.java b/src/main/java/fr/unistra/sil/erp/back/Config.java
index dd7c0537e53030b395dbeb0d048a3ac6c3cfcb5a..ed8cc4d04ba091dec77b3f0b818d535de39bef61 100644
--- a/src/main/java/fr/unistra/sil/erp/back/Config.java
+++ b/src/main/java/fr/unistra/sil/erp/back/Config.java
@@ -10,18 +10,37 @@ package fr.unistra.sil.erp.back;
  */
 public class Config {
     
+    /**
+     * API version.
+     */
     public static final String API_VERSION = "v1";
     
+    /**
+     * Prefix for API calls.
+     */
     public static final String URL_PREFIX = "/api/" + API_VERSION;
     
+    /**
+     * API Mapping for retrieving all items.
+     */
     public static final String MAPPING_RETRIEVEALL = URL_PREFIX +
             "/retrieveAll";
+    
+    /**
+     * API Mapping for retrieving all categories.
+     */
     public static final String MAPPING_GETCATEGORIES = URL_PREFIX +
             "/retrieveCategories";
     
+    /**
+     * API Mapping for submitting transactions.
+     */
     public static final String MAPPING_SUBTRANSAC = URL_PREFIX +
             "/submitTransaction";
     
+    /**
+     * API Mapping for retrieving stocks.
+     */
     public static final String MAPPING_GETSTOCKS = URL_PREFIX +
             "/retrieveStocks";
 }
diff --git a/src/main/java/fr/unistra/sil/erp/back/DatabaseSystem.java b/src/main/java/fr/unistra/sil/erp/back/DatabaseSystem.java
index 321f1193dba8b92d75b88e48189081063483f573..4cdb1f35f2e5c5e21acc56429545d2c7a4388238 100644
--- a/src/main/java/fr/unistra/sil/erp/back/DatabaseSystem.java
+++ b/src/main/java/fr/unistra/sil/erp/back/DatabaseSystem.java
@@ -10,7 +10,7 @@ import fr.unistra.sil.erp.back.db.DatabaseSQLiteImpl;
 
 /**
  * Manages the database implementation to use.
- * @author BEAUVAIS ANTOINE <antoine.beauvais@etu.unistra.fr>
+ * @author BEAUVAIS ANTOINE
  */
 public class DatabaseSystem {
     
diff --git a/src/main/java/fr/unistra/sil/erp/back/controller/IRetrieveStocks.java b/src/main/java/fr/unistra/sil/erp/back/controller/IRetrieveStocks.java
index 883ba1d0be2eff2a4bba39ca484c6248f8332f02..dd9d14b1b09752984e1d01df9134c87ed0180c89 100644
--- a/src/main/java/fr/unistra/sil/erp/back/controller/IRetrieveStocks.java
+++ b/src/main/java/fr/unistra/sil/erp/back/controller/IRetrieveStocks.java
@@ -14,6 +14,13 @@ import org.springframework.http.ResponseEntity;
  */
 public interface IRetrieveStocks {
     
+    /**
+     * Returns the list of stocks to the user.
+     * @param request the HTTP Servlet request, provided by Spring.
+     * @param response the HTTP Servlet response, provided by Spring.
+     * @return the response to the user.
+     * @throws Exception if the query fails.
+     */
     public ResponseEntity<Object> retrieveStocks(HttpServletRequest request,
             HttpServletResponse response) throws Exception;
     
diff --git a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiBadRequestException.java b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiBadRequestException.java
index 7443d03e099094f3e357ca526c2e9d7d4ed61af0..07cf910a9152abcd24a404c6573eda8a140aef97 100644
--- a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiBadRequestException.java
+++ b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiBadRequestException.java
@@ -5,11 +5,26 @@
 package fr.unistra.sil.erp.back.controller.api;
 
 /**
- * HTTP error 400 Bad Request for the API.
+ * HTTP error 400 Bad Request JSON content.
+ * 
+ * If the user sends invalid or incomplete data, the query will typically
+ * fail and this Exception will be thrown.
+ * 
+ * This Exception allows the application to tell the user what went
+ * wrong with his query.
+ * 
+ * Bad Request errors should only be sent if the error is caused by the user's
+ * input. If the error happens because of a server problem,
+ * the ApiServerErrorException should be used instead.
+ * 
  * @author BEAUVAIS ANTOINE
  */
 public class ApiBadRequestException extends Exception {
     
+    /**
+     * Class constructor.
+     * @param errMsg the error message.
+     */
     public ApiBadRequestException(String errMsg)
     {
         super(errMsg);
diff --git a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiErrorHandler.java b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiErrorHandler.java
index 2e85fb611529485eb509262a33e6e22b77bee8cf..fbd17bf756a01709ade1816535a86f93c9e6ac7f 100644
--- a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiErrorHandler.java
+++ b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiErrorHandler.java
@@ -14,11 +14,22 @@ import org.springframework.web.bind.annotation.RestControllerAdvice;
 
 /**
  * Handles API exceptions.
+ * 
+ * When an Exception is thrown while processing a request, the behavior
+ * to adopt for each Exception is defined here.
+ * 
  * @author BEAUVAIS ANTOINE
  */
 @RestControllerAdvice
 public class ApiErrorHandler {
     
+    /**
+     * Handler for HTTP 500 Internal Server Error.
+     * @param ex the thrown Exception.
+     * @param request the HTTP Servlet request, provided by Spring.
+     * @param response the HTTP Servlet response, provided by Spring.
+     * @return the response to the client.
+     */
     @ExceptionHandler(ApiServerErrorException.class)
     public ResponseEntity<Object> handleServerError(Exception ex,
             HttpServletRequest request, HttpServletResponse response)
@@ -27,6 +38,13 @@ public class ApiErrorHandler {
                 HttpStatus.INTERNAL_SERVER_ERROR);
     }
     
+    /**
+     * Handler for HTTP 400 Bad Request.
+     * @param ex the thrown Exception.
+     * @param request the HTTP Servlet request.
+     * @param response the HTTP Servlet response.
+     * @return the response to the client.
+     */
     @ExceptionHandler(ApiBadRequestException.class)
     public ResponseEntity<Object> handleBadRequest(Exception ex,
             HttpServletRequest request, HttpServletResponse response)
diff --git a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveCategoriesController.java b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveCategoriesController.java
index 977b42ac2a0a98e445380991927cef9d2d34fda0..fa4a767df3d1d302acd0bec3952e3620f000e2b8 100644
--- a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveCategoriesController.java
+++ b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveCategoriesController.java
@@ -5,7 +5,6 @@
 package fr.unistra.sil.erp.back.controller.api;
 
 import static fr.unistra.sil.erp.back.Config.MAPPING_GETCATEGORIES;
-import static fr.unistra.sil.erp.back.Config.MAPPING_GETSTOCKS;
 import fr.unistra.sil.erp.back.DatabaseSystem;
 import fr.unistra.sil.erp.back.controller.IRetrieveCategoriesController;
 import fr.unistra.sil.erp.back.model.Category;
diff --git a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveInfoController.java b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveInfoController.java
index 0b9e426bd58c3bd455aa145c897d04478633b97e..ba8c6afd0d04eab84780a06057e61b2683d81868 100644
--- a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveInfoController.java
+++ b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveInfoController.java
@@ -13,7 +13,6 @@ import fr.unistra.sil.erp.back.db.DatabaseInterface;
 import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
-import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
diff --git a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiServerErrorException.java b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiServerErrorException.java
index 7cfe6a04e2f1049bfd5c91c077e507196f95a6ba..2ba9a230f69c3e8d5d601609804648c56dbe5afa 100644
--- a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiServerErrorException.java
+++ b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiServerErrorException.java
@@ -5,11 +5,21 @@
 package fr.unistra.sil.erp.back.controller.api;
 
 /**
- * Returns HTTP 500 error page.
- * @author BEAUVAIS ANTOINE <antoine.beauvais@etu.unistra.fr>
+ * Returns HTTP 500 JSON error.
+ * 
+ * This exception allows the application to handle internal
+ * server errors by replying proper JSON content to the caller.
+ * 
+ * The message will be given to the user.
+ * 
+ * @author BEAUVAIS ANTOINE
  */
 public class ApiServerErrorException extends Exception {
 
+    /**
+     * Class constructor.
+     * @param errMsg the error message to display to the end-user.
+     */
     public ApiServerErrorException(String errMsg)
     {
         super(errMsg);
diff --git a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiSubmitTransactionController.java b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiSubmitTransactionController.java
index 37189f0370ae9e38725a92824cdfaffd27dcf65b..33f6b5c7ff342d2c894671f32e694fbf3f2aebec 100644
--- a/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiSubmitTransactionController.java
+++ b/src/main/java/fr/unistra/sil/erp/back/controller/api/ApiSubmitTransactionController.java
@@ -29,6 +29,13 @@ import org.springframework.web.bind.annotation.RestController;
 public class ApiSubmitTransactionController
         implements ISubmitTransactionController {
     
+    /**
+     * Handler for transaction submissions.
+     * @param request the HTTP Servlet Request provided by Spring.
+     * @param response the HTTP Servlet Response provided by Spring.
+     * @return the response for the user.
+     * @throws ApiBadRequestException if the query failed.
+     */
     @RequestMapping(value=MAPPING_SUBTRANSAC, method = RequestMethod.POST)
     @Override
     public ResponseEntity<Object> submitTransaction(HttpServletRequest request,
diff --git a/src/main/java/fr/unistra/sil/erp/back/db/DatabaseConnectionException.java b/src/main/java/fr/unistra/sil/erp/back/db/DatabaseConnectionException.java
index 1b1598f32054dbcdf412b0c0d9dfda6c4ec24ed2..fcff9c1cf58a937d3a5714023b1aeefc3d0cbe4d 100644
--- a/src/main/java/fr/unistra/sil/erp/back/db/DatabaseConnectionException.java
+++ b/src/main/java/fr/unistra/sil/erp/back/db/DatabaseConnectionException.java
@@ -5,8 +5,14 @@
 package fr.unistra.sil.erp.back.db;
 
 /**
- *
- * @author BEAUVAIS ANTOINE <antoine.beauvais@etu.unistra.fr>
+ * General database error.
+ * 
+ * This is a custom Exception thrown when the database could not
+ * be used by the application, for whatever reason.
+ * 
+ * This allows the program to handle error cases.
+ * 
+ * @author BEAUVAIS ANTOINE
  */
 public class DatabaseConnectionException extends Exception {
     
diff --git a/src/main/java/fr/unistra/sil/erp/back/db/DatabaseInterface.java b/src/main/java/fr/unistra/sil/erp/back/db/DatabaseInterface.java
index 19f0dfa184e3569167a30fda0aa17b2c09ac0709..988daf0d507df0d7f8471b5ff48ac47866c1b3aa 100644
--- a/src/main/java/fr/unistra/sil/erp/back/db/DatabaseInterface.java
+++ b/src/main/java/fr/unistra/sil/erp/back/db/DatabaseInterface.java
@@ -15,7 +15,7 @@ import java.util.List;
  * This interface allows the application to be able to use different
  * database systems (CSV, SQLite, MySQL...) by simply switching
  * implementations.
- * @author BEAUVAIS ANTOINE <antoine.beauvais@etu.unistra.fr>
+ * @author BEAUVAIS ANTOINE
  */
 public interface DatabaseInterface {
     
diff --git a/src/main/java/fr/unistra/sil/erp/back/db/DatabaseSQLiteImpl.java b/src/main/java/fr/unistra/sil/erp/back/db/DatabaseSQLiteImpl.java
index 6ba2ee98f936419de2e1056679f93269a65e6bda..dd162f3ad82e5fc2ec6427d46246f4c3200efac1 100644
--- a/src/main/java/fr/unistra/sil/erp/back/db/DatabaseSQLiteImpl.java
+++ b/src/main/java/fr/unistra/sil/erp/back/db/DatabaseSQLiteImpl.java
@@ -20,27 +20,54 @@ import java.util.logging.Logger;
 
 /**
  * SQLite implementation of the Database interface.
- * @author BEAUVAIS ANTOINE <antoine.beauvais@etu.unistra.fr>
+ * 
+ * This allows the software to store and process information through
+ * a SQLite database file.
+ * 
+ * @author BEAUVAIS ANTOINE
  */
 public class DatabaseSQLiteImpl implements DatabaseInterface {
     
+    /**
+     * SQLite's connection string for the JDBC driver.
+     */
     private static final String CONNECTION_URL = "jdbc:sqlite:dev.db";
+    
+    /**
+     * Query used to select all items stored in the database.
+     */
     private static final String SQL_GETALLITEMS = 
             "SELECT ref, name, price, subscriberPrice, category FROM items";
     
+    /**
+     * Query used to get all items stored in the database from a specific
+     * category.
+     */
     private static final String SQL_GETITEMSFROMCATEGORY = SQL_GETALLITEMS +
             " WHERE category = ?";
     
+    /**
+     * Query used to retrieve all categories stored in the database.
+     */
     private static final String SQL_GETCATEGORIES =
             "SELECT id, name FROM categories";
     
+    /**
+     * Query used to fetch all stocks stored in the database.
+     */
     private static final String SQL_GETSTOCKS = 
             "SELECT s.id AS id, s.item AS item, " +
             "i.name AS name, s.quantity AS quantity FROM stocks s " +
             "INNER JOIN items i ON s.item = i.ref";
     
+    /**
+     * SQL Connection object.
+     */
     private Connection conn;
     
+    /**
+     * Class constructor.
+     */
     public DatabaseSQLiteImpl()
     {
         try {
@@ -51,6 +78,11 @@ public class DatabaseSQLiteImpl implements DatabaseInterface {
         }
     }
     
+    /**
+     * Executes a standard query, without parameters.
+     * @param query the string's query.
+     * @return the result set for this query.
+     */
     private ResultSet query(String query)
     {
         Statement stmt;
@@ -67,6 +99,10 @@ public class DatabaseSQLiteImpl implements DatabaseInterface {
         return rs;
     }
 
+    /**
+     * Retrieves all items from inside the database.
+     * @return the list of items.
+     */
     @Override
     public List<Item> getAllItems() {
         ResultSet rs = query(SQL_GETALLITEMS);
@@ -92,6 +128,11 @@ public class DatabaseSQLiteImpl implements DatabaseInterface {
         return res;
     }
 
+    /**
+     * Returns all items from the specified category.
+     * @param category the category to filter the results with.
+     * @return the list of items.
+     */
     @Override
     public List<Item> getItemsFromCategory(int category) {
         
@@ -141,6 +182,10 @@ public class DatabaseSQLiteImpl implements DatabaseInterface {
         return res;
     }
 
+    /**
+     * Retrieves all categories from the database.
+     * @return the list of categories.
+     */
     @Override
     public List<Category> getCategories() {
         ResultSet rs = this.query(SQL_GETCATEGORIES);
@@ -163,6 +208,10 @@ public class DatabaseSQLiteImpl implements DatabaseInterface {
         return res;
     }
 
+    /**
+     * Retrieves all stock entries from the database.
+     * @return the list of stock entries.
+     */
     @Override
     public List<Stock> getStocks() {
         ResultSet rs = this.query(SQL_GETSTOCKS);
diff --git a/src/main/java/fr/unistra/sil/erp/back/model/ErrorMessage.java b/src/main/java/fr/unistra/sil/erp/back/model/ErrorMessage.java
index c7fac546bdce415764dab989a3718df8bcdf7486..a5d4ba8b7d30831f3bad4eaf397fe7f5292d4b47 100644
--- a/src/main/java/fr/unistra/sil/erp/back/model/ErrorMessage.java
+++ b/src/main/java/fr/unistra/sil/erp/back/model/ErrorMessage.java
@@ -6,17 +6,35 @@ package fr.unistra.sil.erp.back.model;
 
 /**
  * JSON error message.
+ * 
+ * When an error occurs, the application will send this type of message
+ * to the user.
+ * 
+ * This object only provides a simple message to briefly inform the user
+ * of what went wrong with the query.
+ * 
  * @author BEAUVAIS ANTOINE
  */
 public class ErrorMessage {
     
+    /**
+     * The error message.
+     */
     private final String message;
     
+    /**
+     * Class constructor.
+     * @param message the error message to display.
+     */
     public ErrorMessage(String message)
     {
         this.message = message;
     }
     
+    /**
+     * Returns the error message.
+     * @return the message.
+     */
     public String getMessage()
     {
         return this.message;
diff --git a/src/main/java/fr/unistra/sil/erp/back/model/Item.java b/src/main/java/fr/unistra/sil/erp/back/model/Item.java
index b37069dd569ff126f909c26bcde7feda0a1b6ecc..a7586d8deee48044b439f6e5637b6d0788c3019d 100644
--- a/src/main/java/fr/unistra/sil/erp/back/model/Item.java
+++ b/src/main/java/fr/unistra/sil/erp/back/model/Item.java
@@ -7,8 +7,16 @@ package fr.unistra.sil.erp.back.model;
 import java.math.BigDecimal;
 
 /**
- * Item description.
- * @author BEAUVAIS ANTOINE <antoine.beauvais@etu.unistra.fr>
+ * Item object.
+ * 
+ * Items are products that can be bought and sold.
+ * 
+ * Any transaction must be linked to an item.
+ * 
+ * Items have specific quantities stored as "stocks" and cannot be sold
+ * if the quantity is depleted.
+ * 
+ * @author BEAUVAIS ANTOINE
  */
 public class Item {
     
diff --git a/src/main/java/fr/unistra/sil/erp/back/model/RegistryEntry.java b/src/main/java/fr/unistra/sil/erp/back/model/RegistryEntry.java
index 8cb06faaa8db023d4be7aa78248d2d69910e34ed..d3c10b20154d4d63c16c58216616a6b8929d2a90 100644
--- a/src/main/java/fr/unistra/sil/erp/back/model/RegistryEntry.java
+++ b/src/main/java/fr/unistra/sil/erp/back/model/RegistryEntry.java
@@ -8,25 +8,66 @@ import java.math.BigDecimal;
 import java.time.LocalDateTime;
 
 /**
- * Transaction object.
+ * Entry in the Registry.
+ * 
+ * The registry contains all credit and debit operations relative to
+ * the operating organization.
+ * 
  * @author BEAUVAIS ANTOINE
  */
 public class RegistryEntry {
     
+    /**
+     * The entry's ID.
+     */
     private final int id;
-    private final int transactionId;
+    
+    /**
+     * The transaction's type.
+     */
+    private final int transactionType;
+    
+    /**
+     * The date and time for this transaction.
+     */
     private final LocalDateTime dt;
+    
+    /**
+     * The ID of the associated account.
+     */
     private final int accountId;
+    
+    /**
+     * The amount of money, if it's a debit.
+     */
     private final BigDecimal debit;
+    
+    /**
+     * The amount of money, if it's a credit.
+     */
     private final BigDecimal credit;
+    
+    /**
+     * Arbitrary remarks. Optional.
+     */
     private final String remarks;
     
-    public RegistryEntry(int id, int transactionId, LocalDateTime dt,
+    /**
+     * Class constructor.
+     * @param id the entry's ID.
+     * @param transactionType the transaction type.
+     * @param dt the date and time.
+     * @param accountId the associated account's ID.
+     * @param debit money for the debit.
+     * @param credit money for the credit.
+     * @param remarks arbitrary remarks.
+     */
+    public RegistryEntry(int id, int transactionType, LocalDateTime dt,
             int accountId, BigDecimal debit, BigDecimal credit,
             String remarks)
     {
         this.id = id;
-        this.transactionId = transactionId;
+        this.transactionType = transactionType;
         this.dt = dt;
         this.accountId = accountId;
         this.debit = debit;
@@ -34,36 +75,64 @@ public class RegistryEntry {
         this.remarks = remarks;
     }
     
+    /**
+     * Returns the entry's ID.
+     * @return the entry's ID.
+     */
     public int getId()
     {
         return this.id;
     }
     
-    public int getTransactionId()
+    /**
+     * Returns the transaction's type.
+     * @return the transaction's type.
+     */
+    public int getTransactionType()
     {
-        return this.transactionId;
+        return this.transactionType;
     }
     
+    /**
+     * Returns the transaction's date and time.
+     * @return the date and time.
+     */
     public LocalDateTime getDatetime()
     {
         return this.dt;
     }
     
+    /**
+     * Returns the associated account's ID.
+     * @return the associated account's ID.
+     */
     public int getAccountId()
     {
         return this.accountId;
     }
     
+    /**
+     * Returns the debit amount.
+     * @return the amount.
+     */
     public BigDecimal getDebit()
     {
         return this.debit;
     }
     
+    /**
+     * Returns the credit amount.
+     * @return the amount.
+     */
     public BigDecimal getCredit()
     {
         return this.credit;
     }
     
+    /**
+     * Returns the arbitrary remarks.
+     * @return the remarks.
+     */
     public String getRemarks()
     {
         return this.remarks;
diff --git a/src/main/java/fr/unistra/sil/erp/back/model/Stock.java b/src/main/java/fr/unistra/sil/erp/back/model/Stock.java
index 05c950448c5e4a89406c296a2247d2177401cc36..b2c8dd22067b455f92783355e91017c8f84e1f8d 100644
--- a/src/main/java/fr/unistra/sil/erp/back/model/Stock.java
+++ b/src/main/java/fr/unistra/sil/erp/back/model/Stock.java
@@ -6,18 +6,42 @@ package fr.unistra.sil.erp.back.model;
 
 /**
  * Representation of a stock entry.
+ * 
+ * Stocks simply provide the available quantity for each item.
+ * 
+ * If an item's quantity is depleted, it cannot be sold.
+ * 
  * @author BEAUVAIS ANTOINE
  */
 public class Stock {
     
+    /**
+     * The stock entry's ID.
+     */
     private final int id;
     
+    /**
+     * The stock's item ID.
+     */
     private final int itemId;
     
+    /**
+     * The stock's item name.
+     */
     private final String itemName;
     
+    /**
+     * The quantity for the item.
+     */
     private final int quantity;
     
+    /**
+     * Class constructor.
+     * @param id the Stock's ID.
+     * @param itemId the item's ID.
+     * @param itemName the item's name.
+     * @param quantity the quantity.
+     */
     public Stock(int id, int itemId, String itemName, int quantity)
     {
         this.id = id;
@@ -26,21 +50,37 @@ public class Stock {
         this.quantity = quantity;
     }
     
+    /**
+     * Returns the stock ID.
+     * @return the stock's ID.
+     */
     public int getId()
     {
         return this.id;
     }
     
+    /**
+     * Returns the item's ID.
+     * @return the item's ID.
+     */
     public int getItemId()
     {
         return this.itemId;
     }
     
+    /**
+     * Returns the item's name.
+     * @return the item's name.
+     */
     public String getItemName()
     {
         return this.itemName;
     }
     
+    /**
+     * Returns the quantity for the item.
+     * @return the quantity.
+     */
     public int getQuantity()
     {
         return this.quantity;
diff --git a/src/main/java/fr/unistra/sil/erp/back/model/Transaction.java b/src/main/java/fr/unistra/sil/erp/back/model/Transaction.java
index b4eadecb89526c673987a594a6b23b2c5cf71c3e..205760b66b477945134ff14fe363bb59c49ba44d 100644
--- a/src/main/java/fr/unistra/sil/erp/back/model/Transaction.java
+++ b/src/main/java/fr/unistra/sil/erp/back/model/Transaction.java
@@ -8,18 +8,44 @@ import java.math.BigDecimal;
 
 /**
  * Representation of a transaction.
+ * 
+ * A Transaction is a query from the MONEY component that represents
+ * the information used for a proper transaction.
+ * 
+ * Transactions automatically update stocks as well as the Registry
+ * when applicable.
+ * 
  * @author BEAUVAIS ANTOINE
  */
 public class Transaction {
     
+    /**
+     * Item ID.
+     */
     private final Integer item;
     
+    /**
+     * Transaction type.
+     */
     private final Integer type;
     
+    /**
+     * Transaction's amount.
+     */
     private final BigDecimal amount;
     
+    /**
+     * Number of items.
+     */
     private final Integer quantity;
     
+    /**
+     * Class constructor.
+     * @param item Item's identifier.
+     * @param type Transaction type.
+     * @param amount Transaction's amount.
+     * @param quantity Quantity of items involved.
+     */
     public Transaction(Integer item, Integer type, BigDecimal amount,
             Integer quantity)
     {
@@ -29,26 +55,46 @@ public class Transaction {
         this.quantity = quantity;
     }
     
+    /**
+     * Returns the Transaction's item ID.
+     * @return the item ID.
+     */
     public Integer getItem()
     {
         return this.item;
     }
     
+    /**
+     * Returns the Transaction's type.
+     * @return the transaction's type.
+     */
     public Integer getType()
     {
         return this.type;
     }
     
+    /**
+     * Returns the Transaction's amount of money.
+     * @return the amount.
+     */
     public BigDecimal getAmount()
     {
         return this.amount;
     }
     
+    /**
+     * Returns the number of items in the Transaction.
+     * @return the number of items.
+     */
     public Integer getQuantity()
     {
         return this.quantity;
     }
     
+    /**
+     * Checks that the Transaction is valid.
+     * @return whether the Transaction is valid.
+     */
     public boolean checkIfValid()
     {
         return (this.item != null && this.type != null