diff --git a/src/main/java/seedu/address/commons/util/DateUtil.java b/src/main/java/seedu/address/commons/util/DateUtil.java
index 686ba223806..3de2e28110f 100644
--- a/src/main/java/seedu/address/commons/util/DateUtil.java
+++ b/src/main/java/seedu/address/commons/util/DateUtil.java
@@ -11,7 +11,8 @@ public class DateUtil {
 
     public static final String MESSAGE_CONSTRAINTS_FORMAT = "%1$s takes in a date of format dd/MM/yyyy";
     public static final String MESSAGE_CONSTRAINTS_FUTURE_OCCURRENCE = "%1$s should not be later than current date";
-    private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");
+
+    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("dd/MM/yyyy");
 
     /**
      * Returns true if a given string is a valid date.
@@ -20,7 +21,7 @@ public class DateUtil {
      */
     public static boolean isValidDate(String value) {
         try {
-            LocalDate date = LocalDate.parse(value, formatter);
+            LocalDate date = LocalDate.parse(value, FORMATTER);
             return true;
         } catch (DateTimeParseException e) {
             return false;
@@ -33,7 +34,7 @@ public static boolean isValidDate(String value) {
      */
     public static boolean isFutureDate(String value) {
         if (isValidDate(value)) {
-            LocalDate date = LocalDate.parse(value, formatter);
+            LocalDate date = LocalDate.parse(value, FORMATTER);
             return date.isAfter(LocalDate.now());
         }
         return false;
@@ -43,6 +44,6 @@ public static boolean isFutureDate(String value) {
      * Returns the formatter for the date.
      */
     public static DateTimeFormatter getFormatter() {
-        return formatter;
+        return FORMATTER;
     }
 }
diff --git a/src/main/java/seedu/address/logic/commands/AddCommand.java b/src/main/java/seedu/address/logic/commands/AddCommand.java
index 15ea1cd2713..cfb1d939bea 100644
--- a/src/main/java/seedu/address/logic/commands/AddCommand.java
+++ b/src/main/java/seedu/address/logic/commands/AddCommand.java
@@ -20,6 +20,7 @@
  * Adds a person to the address book.
  */
 public class AddCommand extends Command {
+
     public static final String COMMAND_WORD = "add";
     public static final String MESSAGE_USAGE = COMMAND_WORD + ": Adds a person to the address book. \n"
             + "Parameters: "
@@ -39,7 +40,6 @@ public class AddCommand extends Command {
             + PREFIX_REMARK + "Prevent bed sores. "
             + PREFIX_TAG + "FallRisk";
     public static final String MESSAGE_SUCCESS = "New patient added: %1$s";
-
     public static final String MESSAGE_DUPLICATE_PERSON = "A patient with this IC already exists in the address book";
 
     private final Person toAdd;
diff --git a/src/main/java/seedu/address/logic/commands/EditCommand.java b/src/main/java/seedu/address/logic/commands/EditCommand.java
index 50e8efce215..d35b1922a91 100644
--- a/src/main/java/seedu/address/logic/commands/EditCommand.java
+++ b/src/main/java/seedu/address/logic/commands/EditCommand.java
@@ -207,36 +207,47 @@ public void setTags(Set<Tag> tags) {
         public Optional<Set<Tag>> getTags() {
             return (tags != null) ? Optional.of(Collections.unmodifiableSet(tags)) : Optional.empty();
         }
+
         public void setIc(Ic ic) {
             this.ic = ic;
         }
+
         public Optional<Ic> getIc() {
             return Optional.ofNullable(ic);
         }
+
         public void setDob(Dob dob) {
             this.dob = dob;
         }
+
         public Optional<Dob> getDob() {
             return Optional.ofNullable(dob);
         }
+
         public void setAdmissionDate(AdmissionDate admissionDate) {
             this.admissionDate = admissionDate;
         }
+
         public Optional<AdmissionDate> getAdmissionDate() {
             return Optional.ofNullable(admissionDate);
         }
+
         public void setWard(Ward ward) {
             this.ward = ward;
         }
+
         public Optional<Ward> getWard() {
             return Optional.ofNullable(ward);
         }
+
         public void setRemark(Remark remark) {
             this.remark = remark;
         }
+
         public Optional<Remark> getRemark() {
             return Optional.ofNullable(remark);
         }
+
         @Override
         public boolean equals(Object other) {
             if (other == this) {
diff --git a/src/main/java/seedu/address/logic/commands/ExitCommand.java b/src/main/java/seedu/address/logic/commands/ExitCommand.java
index 3dd85a8ba90..4f52a0c5f8a 100644
--- a/src/main/java/seedu/address/logic/commands/ExitCommand.java
+++ b/src/main/java/seedu/address/logic/commands/ExitCommand.java
@@ -13,6 +13,7 @@ public class ExitCommand extends Command {
 
     @Override
     public CommandResult execute(Model model) {
+
         return new CommandResult(MESSAGE_EXIT_ACKNOWLEDGEMENT, false, true);
     }
 
diff --git a/src/main/java/seedu/address/logic/commands/ListCommand.java b/src/main/java/seedu/address/logic/commands/ListCommand.java
index b0cf87265e7..d485a5f3f11 100644
--- a/src/main/java/seedu/address/logic/commands/ListCommand.java
+++ b/src/main/java/seedu/address/logic/commands/ListCommand.java
@@ -26,6 +26,7 @@ public class ListCommand extends Command {
 
     public static final String MESSAGE_SUCCESS = "Listed all persons";
     public static final String MESSAGE_SUCCESS_LIST = "Listed all persons with: %1$s";
+
     private final ListKeywordsPredicate predicate;
 
     /**
@@ -74,7 +75,7 @@ public boolean equals(Object other) {
     @Override
     public String toString() {
         return new ToStringBuilder(this)
-                .add("predicate", predicate == null ? "null" : predicate)
+                .add("predicate", (predicate == null) ? "null" : predicate)
                 .toString();
     }
 }
diff --git a/src/main/java/seedu/address/logic/parser/AddCommandParser.java b/src/main/java/seedu/address/logic/parser/AddCommandParser.java
index db08ec6a57c..5c2eecf620b 100644
--- a/src/main/java/seedu/address/logic/parser/AddCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/AddCommandParser.java
@@ -31,6 +31,7 @@ public class AddCommandParser implements Parser<AddCommand> {
     /**
      * Parses the given {@code String} of arguments in the context of the AddCommand
      * and returns an AddCommand object for execution.
+     *
      * @throws ParseException if the user input does not conform the expected format
      */
     public AddCommand parse(String args) throws ParseException {
diff --git a/src/main/java/seedu/address/logic/parser/DeleteCommandParser.java b/src/main/java/seedu/address/logic/parser/DeleteCommandParser.java
index 3527fe76a3e..4e29d82d253 100644
--- a/src/main/java/seedu/address/logic/parser/DeleteCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/DeleteCommandParser.java
@@ -14,6 +14,7 @@ public class DeleteCommandParser implements Parser<DeleteCommand> {
     /**
      * Parses the given {@code String} of arguments in the context of the DeleteCommand
      * and returns a DeleteCommand object for execution.
+     *
      * @throws ParseException if the user input does not conform the expected format
      */
     public DeleteCommand parse(String args) throws ParseException {
diff --git a/src/main/java/seedu/address/logic/parser/EditCommandParser.java b/src/main/java/seedu/address/logic/parser/EditCommandParser.java
index 1e6c727f895..a50cc27fa3e 100644
--- a/src/main/java/seedu/address/logic/parser/EditCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/EditCommandParser.java
@@ -29,6 +29,7 @@ public class EditCommandParser implements Parser<EditCommand> {
     /**
      * Parses the given {@code String} of arguments in the context of the EditCommand
      * and returns an EditCommand object for execution.
+     *
      * @throws ParseException if the user input does not conform the expected format
      */
     public EditCommand parse(String args) throws ParseException {
diff --git a/src/main/java/seedu/address/logic/parser/FindCommandParser.java b/src/main/java/seedu/address/logic/parser/FindCommandParser.java
index 8bb6a82ca12..b46ea16c092 100644
--- a/src/main/java/seedu/address/logic/parser/FindCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/FindCommandParser.java
@@ -20,6 +20,7 @@ public class FindCommandParser implements Parser<FindCommand> {
     /**
      * Parses the given {@code String} of arguments in the context of the FindCommand
      * and returns a FindCommand object for execution.
+     *
      * @throws ParseException if the user input does not conform the expected format
      */
     public FindCommand parse(String args) throws ParseException {
diff --git a/src/main/java/seedu/address/logic/parser/ListCommandParser.java b/src/main/java/seedu/address/logic/parser/ListCommandParser.java
index 96464fe5320..daba20edaee 100644
--- a/src/main/java/seedu/address/logic/parser/ListCommandParser.java
+++ b/src/main/java/seedu/address/logic/parser/ListCommandParser.java
@@ -19,18 +19,21 @@ public class ListCommandParser implements Parser<ListCommand> {
     /**
      * Parses the given {@code String} of arguments in the context of the ListCommand
      * and returns a ListCommand object for execution.
+     *
+     * @param args the arguments to parse.
+     * @return a ListCommand object for execution.
      * @throws ParseException if the user input does not conform the expected format
      */
     public ListCommand parse(String args) throws ParseException {
         String trimmedArgs = args.trim();
-        // If there are no arguments, return a ListCommand object with no predicate
+
+        // If there are no arguments, list all patients
         if (trimmedArgs.isEmpty()) {
-            return new ListCommand(); // return a ListCommand object with no predicate
+            return new ListCommand();
         }
 
-        // If there are arguments, parse the arguments and return a ListCommand object with the parsed predicate
-        ArgumentMultimap argMultimap =
-                ArgumentTokenizer.tokenize(args, PREFIX_TAG, PREFIX_WARD);
+        // If there are arguments, filter patients based on the arguments
+        ArgumentMultimap argMultimap = ArgumentTokenizer.tokenize(args, PREFIX_TAG, PREFIX_WARD);
         if (!argMultimap.getPreamble().isEmpty()) {
             throw new ParseException(String.format(MESSAGE_INVALID_COMMAND_FORMAT, ListCommand.MESSAGE_USAGE));
         }
@@ -39,20 +42,20 @@ public ListCommand parse(String args) throws ParseException {
         List<String> tagList = List.of();
         if (arePrefixesPresent(argMultimap, PREFIX_TAG)) {
             tagList = ParserUtil.parseTagsKeywords(argMultimap.getAllValues(PREFIX_TAG));
-            assert !tagList.isEmpty();
+            assert !tagList.isEmpty() : "tagList should not be empty";
         }
 
         String ward = "";
         if (arePrefixesPresent(argMultimap, PREFIX_WARD)) {
             ward = ParserUtil.parseWard(argMultimap.getValue(PREFIX_WARD).orElse(null)).toString();
-            assert !ward.isEmpty();
+            assert !ward.isEmpty() : "ward should not be empty";
         }
 
-        if (ward.isEmpty() && tagList.isEmpty()) { // If there are no valid arguments, throw an exception
+        if (ward.isEmpty() && tagList.isEmpty()) {
             throw new ParseException(String.format(MESSAGE_INVALID_COMMAND_FORMAT, ListCommand.MESSAGE_USAGE));
         }
 
-        assert !tagList.isEmpty() || !ward.isEmpty();
+        assert !tagList.isEmpty() || !ward.isEmpty() : "at least either tagList or ward must be supplied";
 
         return new ListCommand(new ListKeywordsPredicate(tagList, ward));
     }
@@ -60,6 +63,9 @@ public ListCommand parse(String args) throws ParseException {
     /**
      * Returns true if none of the prefixes contains empty {@code Optional} values in the given
      * {@code ArgumentMultimap}.
+     *
+     * @param argumentMultimap the {@code ArgumentMultimap} to check for the presence of prefixes.
+     * @param prefixes the prefixes to check for.
      */
     private static boolean arePrefixesPresent(ArgumentMultimap argumentMultimap, Prefix... prefixes) {
         return Stream.of(prefixes).allMatch(prefix -> argumentMultimap.getValue(prefix).isPresent());
diff --git a/src/main/java/seedu/address/logic/parser/ParserUtil.java b/src/main/java/seedu/address/logic/parser/ParserUtil.java
index 11f15588683..7e1d702191a 100644
--- a/src/main/java/seedu/address/logic/parser/ParserUtil.java
+++ b/src/main/java/seedu/address/logic/parser/ParserUtil.java
@@ -128,7 +128,7 @@ public static Ic parseIc(String ic) throws ParseException {
     }
 
     /**
-     * Parses a {@code String admissionDate, Dob dob} into a {@code AdmissionDate}.
+     * Parses a {@code String admissionDate} into a {@code AdmissionDate}.
      * Leading and trailing whitespaces will be trimmed.
      *
      * @throws ParseException if the given {@code admissionDate} is invalid.
@@ -163,7 +163,7 @@ public static Ward parseWard(String ward) throws ParseException {
      * Parses a {@code String remark} into a {@code Remark}.
      * Leading and trailing whitespaces will be trimmed.
      */
-    public static Remark parseRemark(String remark) throws ParseException {
+    public static Remark parseRemark(String remark) {
         if (remark == null) {
             return new Remark("");
         } else {
diff --git a/src/main/java/seedu/address/logic/parser/Prefix.java b/src/main/java/seedu/address/logic/parser/Prefix.java
index 348b7686c8a..8c0a829988f 100644
--- a/src/main/java/seedu/address/logic/parser/Prefix.java
+++ b/src/main/java/seedu/address/logic/parser/Prefix.java
@@ -7,10 +7,20 @@
 public class Prefix {
     private final String prefix;
 
+    /**
+     * Constructs a Prefix object.
+     *
+     * @param prefix A valid prefix.
+     */
     public Prefix(String prefix) {
         this.prefix = prefix;
     }
 
+    /**
+     * Returns the prefix string.
+     *
+     * @return Prefix string.
+     */
     public String getPrefix() {
         return prefix;
     }
diff --git a/src/main/java/seedu/address/model/person/AdmissionDate.java b/src/main/java/seedu/address/model/person/AdmissionDate.java
index b3f112accec..fcc18a1ae5f 100644
--- a/src/main/java/seedu/address/model/person/AdmissionDate.java
+++ b/src/main/java/seedu/address/model/person/AdmissionDate.java
@@ -12,10 +12,10 @@
  */
 public class AdmissionDate extends DateUtil {
     public static final String DATE_TYPE = "Admission date";
-    public static final String MESSAGE_CONSTRAINTS_FORMAT =
-            String.format(DateUtil.MESSAGE_CONSTRAINTS_FORMAT, DATE_TYPE);
-    public static final String MESSAGE_CONSTRAINTS_OCCURRENCE =
-            "Admission date should not be earlier than date of birth or later than current date";
+    public static final String MESSAGE_CONSTRAINTS_FORMAT = String
+            .format(DateUtil.MESSAGE_CONSTRAINTS_FORMAT, DATE_TYPE);
+    public static final String MESSAGE_CONSTRAINTS_OCCURRENCE = String
+            .format("%1$s should not be earlier than date of birth or later than current date", DATE_TYPE);
 
     private final LocalDate admissionDate;
     private final String value;
@@ -51,6 +51,7 @@ public boolean equals(Object other) {
             return true;
         }
 
+        // instanceof handles nulls
         if (!(other instanceof AdmissionDate)) {
             return false;
         }
diff --git a/src/main/java/seedu/address/model/person/Dob.java b/src/main/java/seedu/address/model/person/Dob.java
index 00ef26e98ad..08837710c1a 100644
--- a/src/main/java/seedu/address/model/person/Dob.java
+++ b/src/main/java/seedu/address/model/person/Dob.java
@@ -17,11 +17,11 @@ public class Dob extends DateUtil {
             String.format(DateUtil.MESSAGE_CONSTRAINTS_FORMAT, DATE_TYPE);
     public static final String MESSAGE_CONSTRAINTS_FUTURE_OCCURRENCE =
             String.format(DateUtil.MESSAGE_CONSTRAINTS_FUTURE_OCCURRENCE, DATE_TYPE);
-
     public static final String MESSAGE_DOB_AFTER_ADMISSION =
             "Date of birth should not be later than date of admission.";
 
-    private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");
+    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("dd/MM/yyyy");
+
     private final LocalDate dob;
     private final String value;
 
@@ -34,7 +34,7 @@ public Dob(String value) {
         requireNonNull(value);
         checkArgument(isValidDate(value), MESSAGE_CONSTRAINTS_FORMAT);
         checkArgument(!isFutureDate(value), MESSAGE_CONSTRAINTS_FUTURE_OCCURRENCE);
-        this.dob = LocalDate.parse(value, formatter);
+        this.dob = LocalDate.parse(value, FORMATTER);
         this.value = value;
     }
 
@@ -63,6 +63,7 @@ public boolean equals(Object other) {
             return true;
         }
 
+        // instanceof handles nulls
         if (!(other instanceof Dob)) {
             return false;
         }
diff --git a/src/main/java/seedu/address/model/person/Ic.java b/src/main/java/seedu/address/model/person/Ic.java
index e91b2ce790b..7150981e627 100644
--- a/src/main/java/seedu/address/model/person/Ic.java
+++ b/src/main/java/seedu/address/model/person/Ic.java
@@ -45,6 +45,7 @@ public boolean equals(Object other) {
             return true;
         }
 
+        // instanceof handles nulls
         if (!(other instanceof Ic)) {
             return false;
         }
diff --git a/src/main/java/seedu/address/model/util/SampleDataUtil.java b/src/main/java/seedu/address/model/util/SampleDataUtil.java
index 99db8560eec..16ef97974ac 100644
--- a/src/main/java/seedu/address/model/util/SampleDataUtil.java
+++ b/src/main/java/seedu/address/model/util/SampleDataUtil.java
@@ -20,6 +20,10 @@
  * Contains utility methods for populating {@code AddressBook} with sample data.
  */
 public class SampleDataUtil {
+
+    /**
+     * Returns an array of sample persons.
+     */
     public static Person[] getSamplePersons() {
         return new Person[]{
 
@@ -40,6 +44,9 @@ public static Person[] getSamplePersons() {
         };
     }
 
+    /**
+     * Returns an address book containing sample persons.
+     */
     public static ReadOnlyAddressBook getSampleAddressBook() {
         AddressBook sampleAb = new AddressBook();
         for (Person samplePerson : getSamplePersons()) {