diff --git a/src/model/Library.java b/src/model/Library.java
index 29f2c60..867f4f6 100644
--- a/src/model/Library.java
+++ b/src/model/Library.java
@@ -1,5 +1,7 @@
 package model;
-
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
 import java.util.List;
 
 public class Library {
@@ -7,74 +9,135 @@ public class Library {
   private List<Student> students;
   private List<Category> categories;
   private List<Loan> loans;
+//Constructor
+  public Library(){
+      books=new ArrayList<>();
+      students=new ArrayList<>();
+      categories=new ArrayList<>();
+      loans=new ArrayList<>();
+  }
 
   public void addBook(Book book) {
-    // TODO: Implement method 'addBook'.
-    throw new UnsupportedOperationException("Unimplemented method 'addBook'");
+      books.add(book);
   }
 
   public void removeBook(String isbn) {
-    // TODO: Implement method 'removeBook'.
-    throw new UnsupportedOperationException("Unimplemented method 'removeBook'");
+      for (Book book : books) {
+            if(book.getIsbn().equals(isbn)){
+                  books.remove(book);
+            }
+      }
   }
 
-  public void searchBookByTitle(String title) {
-    // TODO: Implement method 'searchBookByTitle'.
-    throw new UnsupportedOperationException("Unimplemented method 'searchBookByTitle'");
+  public Book searchBookByTitle(String title) {
+      for(Book book : books){
+            if(book.getTitle().equals(title)){
+                  return book;
+            }
+      }
+      return null;
   }
 
-  public void searchBookByISBN(String isbn) {
-    // TODO: Implement method 'searchBookByISBN'.
-    throw new UnsupportedOperationException("Unimplemented method 'searchBookByISBN'");
+  public Book searchBookByISBN(String isbn) {
+            for(Book book : books){
+            if(book.getIsbn().equals(isbn)){
+                  return book;
+            }
+      }
+      return null;
   }
 
-  public void getAvailableBooks() {
-    // TODO: Implement method 'getAvailableBooks'.
-    throw new UnsupportedOperationException("Unimplemented method 'getAvailableBooks'");
+  public List<Book> getAvailableBooks() {
+      List<Book> AvailableBooks=new ArrayList<>();
+      for(Book book : books){
+            if(!book.getIsBorrowed()){
+                  AvailableBooks.add(book);
+            }
+      }
+      return AvailableBooks;
   }
 
   public void addStudent(Student student) {
-    // TODO: Implement method 'addStudent'.
-    throw new UnsupportedOperationException("Unimplemented method 'addStudent'");
+      students.add(student);
   }
 
   public void removeStudent(String studentId) {
-    // TODO: Implement method 'removeStudent'.
-    throw new UnsupportedOperationException("Unimplemented method 'removeStudent'");
+      for(Student student : students){
+            if(student.getStudentId().equals(studentId)){
+                  students.remove(student);
+            }
+      }
   }
 
-  public void searchStudentById(String studentId) {
-    // TODO: Implement method 'searchStudentById'.
-    throw new UnsupportedOperationException("Unimplemented method 'searchStudentById'");
+  public Student searchStudentById(String studentId) {
+      for(Student student : students){
+            if(student.getStudentId().equals(studentId)){
+                  return student;
+            }
+      }
+      return null;
   }
 
-  public void getAllStudents() {
-    // TODO: Implement method 'getAllStudents'.
-    throw new UnsupportedOperationException("Unimplemented method 'getAllStudents'");
+  public List<Student> getAllStudents() {
+      return students;
   }
 
-  public void borrowBook(Book book, Student student) {
-    // TODO: Implement method 'borrowBook'.
-    throw new UnsupportedOperationException("Unimplemented method 'borrowBook'");
+  public boolean borrowBook(Book book, Student student) {
+      if(book.getIsBorrowed()){
+            return false;
+      }
+
+      Date loanDate=new Date();
+      Calendar calendar= Calendar.getInstance();
+      calendar.setTime(loanDate);
+      calendar.add(Calendar.DAY_OF_MONTH,10);
+      Date dueDate = calendar.getTime();
+      book.borrowBook();
+      Loan loan=new Loan(book,student,loanDate,dueDate);
+      loans.add(loan);
+      return true;
   }
 
-  public void returnBook(Book book) {
-    // TODO: Implement method 'returnBook'.
-    throw new UnsupportedOperationException("Unimplemented method 'returnBook'");
-  }
 
-  public void getBorrowedBooksByStudent(String studentId) {
-    // TODO: Implement method 'getBorrowedBooksByStudent'.
-    throw new UnsupportedOperationException("Unimplemented method 'getBorrowedBooksByStudent'");
+  public boolean returnBook(Book book) {
+      for(Loan loan :loans){
+            if(loan.getBook().equals(book)){
+                  loans.remove(loan);
+                  loan.getBook().returnBook();
+                  return true;
+            }
+      }
+      return false;
   }
 
-  public void getBooksByCategory(String categoryName) {
-    // TODO: Implement method 'getBooksByCategory'.
-    throw new UnsupportedOperationException("Unimplemented method 'getBooksByCategory'");
+  public List<Book> getBorrowedBooksByStudent(String studentId) {
+      List<Book> borrowedBooks=new ArrayList<>();
+      for(Loan loan : loans){
+            if(loan.getStudent().studentId.equals(studentId)){
+                  borrowedBooks.add(loan.getBook());
+            }
+      }
+      return borrowedBooks;
   }
 
-  public void getStudentsByMajor(String major) {
-    // TODO: Implement method 'getStudentsByMajor'.
+  public void  getBooksByCategory(String categoryName) {
+      /*for(Category category : categories){
+            if(category.getName().equals(categoryName)){
+
+            }
+      } */
+         // TODO: Implement method 'getStudentsByMajor'.
     throw new UnsupportedOperationException("Unimplemented method 'getStudentsByMajor'");
+
+  }
+
+  public List<Student> getStudentsByMajor(String major) {
+      List<Student> studentsByMajor=new ArrayList<>();
+      for(Student student :students){
+            if(student.getMajor().equals(major)){
+                  studentsByMajor.add(student);
+            }
+      }
+      return studentsByMajor;
   }
 }