Fix 5 SonarQube code quality violations across utility and servlet classes - #10

Location: src/main/java/demo/security/util/DBUtils.java:82

Why is this an issue?

A for loop termination condition should test the loop counter against an invariant value that does not change during the execution of the loop. Invariant termination conditions make the program logic easier to understand and maintain.

What changed

Removes the faulty inner for loop. Its header declared the counter m but tested and incremented the outer loop variable i, so the loop changed a counter the outer loop also controls. Because m never advanced, the loop added no real logic. Deleting it removes the non-invariant loop counter assignment the scanner flagged.

--- a/src/main/java/demo/security/util/DBUtils.java
+++ b/src/main/java/demo/security/util/DBUtils.java
@@ -82,6 +85,0 @@ public class DBUtils {
-                    for (int m = 2; i <= number / 2; i++) {
-                        if (number % m == 0) {
-                            count++;
-                            break;
-                        }
-                    }

Location: src/main/java/demo/security/util/DBUtils.java:96

Why is this an issue?

In software development, logs serve as a record of events within an application, providing crucial insights for debugging. When logging, it is essential to ensure that the logs are:

What changed

Imports java.util.logging.Level and java.util.logging.Logger. The new logger field and the guarded logging call that replace the direct System.out output depend on these imports.

--- a/src/main/java/demo/security/util/DBUtils.java
+++ b/src/main/java/demo/security/util/DBUtils.java
@@ -9,0 +10,2 @@ import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;

Location: src/main/java/demo/security/servlet/HomeServlet.java:30

Why is this an issue?

While not mandatory, using the @Override annotation on compliant methods improves readability by making it explicit that methods are overridden.

What changed

The scanner flagged doPost(HttpServletRequest, HttpServletResponse) in HomeServlet because it overrides HttpServlet.doPost without saying so. This hunk adds the @OverRide annotation directly above that method. That makes the override explicit to readers. It also lets the compiler check that the method really overrides a parent method, so a signature typo would be caught at compile time.

--- a/src/main/java/demo/security/servlet/HomeServlet.java
+++ b/src/main/java/demo/security/servlet/HomeServlet.java
@@ -29,0 +30,1 @@ public class HomeServlet extends HttpServlet {
+    @Override

Location: src/main/java/demo/security/servlet/Insecure.java:35

Why is this an issue?

Throwing generic exceptions such as Error, RuntimeException, Throwable, and Exception will have a negative impact on any code trying to catch these exceptions.

What changed

Adds the java.sql.SQLException import. The two method signatures need it so they can declare this specific exception instead of the generic Exception.

--- a/src/main/java/demo/security/servlet/Insecure.java
+++ b/src/main/java/demo/security/servlet/Insecure.java
@@ -11,0 +12,1 @@ import java.sql.ResultSet;
+import java.sql.SQLException;