added extra comments

.idea/workspace.xml

@@ -2,9 +2,6 @@
 <project version="4">
   <component name="ChangeListManager">
     <list default="true" id="721d25be-807f-4a41-a78a-d223bc93b2f4" name="Default Changelist" comment="">
-      <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/out/production/Run/Lab.class" beforeDir="false" afterPath="$PROJECT_DIR$/out/production/Run/Lab.class" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/out/production/Run/Run.class" beforeDir="false" afterPath="$PROJECT_DIR$/out/production/Run/Run.class" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/src/Lab.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/Lab.java" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/src/Run.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/Run.java" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/src/Student.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/Student.java" afterDir="false" />
@@ -91,5 +88,9 @@
       <screen x="0" y="0" width="1366" height="728" />
     </state>
     <state x="184" y="0" key="SettingsEditor/0.0.1366.728@0.0.1366.728" timestamp="1583493438190" />
+    <state x="346" y="49" width="672" height="678" key="search.everywhere.popup" timestamp="1583505236397">
+      <screen x="0" y="0" width="1366" height="728" />
+    </state>
+    <state x="346" y="49" width="672" height="678" key="search.everywhere.popup/0.0.1366.728@0.0.1366.728" timestamp="1583505236397" />
   </component>
 </project>
\ No newline at end of file

src/Lab.java

@@ -21,6 +21,7 @@ public class Lab {
 
     /**
      * checks if the student can enroll to the class
+     * according to the current size and the capacity
      */
     public void enrollment(Student std) {
         if (currentSize < capacity) {
@@ -33,7 +34,9 @@ public class Lab {
     }
 
     /**
-     * prints
+     * prints the students and
+     * also the average which is
+     * calculated
      */
     public void print() {
         /*
@@ -87,7 +90,8 @@ public class Lab {
     }
 
     /**
-     * calculates the students average
+     * this method is used to
+     * calculate the students average
      */
     public void calculateAvg() {
         int sum = 0;

src/Run.java

@@ -33,8 +33,10 @@ public class Run {
         std1.setGrade(20);
         std2.setGrade(19);
 
+        //setting an invalid ID which result in an error because it has 8 digits
+        std3.setId("98328392");
 
-        //setting the new ID
+        //setting the new valid ID
         std3.setId("9034212");
 
         //initializing the students in the array

src/Student.java

@@ -48,19 +48,43 @@ public class Student {
         else
             System.out.println("error grade");
     }
+
+    /**
+     * a normal getter for grade
+     * @return grade which is the students grade
+     */
     public int getGrade(){
         return grade;
     }
-    public void setId(String fId){
-        if( fId.length() == 7 ) {
-            id = fId;
+
+    /**
+     * this method will reset the students ID
+     * according to its digit counts if the input
+     * has more or less than 7 digits the method
+     * will print an error
+     * @param id is the new student ID
+     */
+    public void setId(String id){
+        if( id.length() == 7 ) {
+            this.id = id;
         }
         else
             System.out.println("error");
     }
+
+    /**
+     * a normal getter which returns the ID
+     * @return id which is the students ID
+     */
     public String getId(){
         return id;
     }
+
+    /**
+     * getLastName method is used to return the students last name
+     * @return lastName which is the students last name
+     * and is used in the Lab class
+     */
     public  String getLastName(){
         return lastName;
     }