diff --git a/database/init_script.sql b/database/init_script.sql
index 1b99ef4..c85d44c 100644
--- a/database/init_script.sql
+++ b/database/init_script.sql
@@ -48,9 +48,10 @@ CREATE TABLE IF NOT EXISTS Book (
 );
 
 CREATE TABLE IF NOT EXISTS BookCategory (
+    bookcategory_id INT NOT Null AUTO_INCREMENT,
 	book_id INT NOT NULL,
 	category_id INT NOT NULL,
-	PRIMARY KEY (book_id, category_id),
+	PRIMARY KEY (bookcategory_id, book_id, category_id),
 	KEY fk_book (book_id),
 	KEY fk_category (category_id),
 	CONSTRAINT fk_book FOREIGN KEY (book_id) REFERENCES Book (book_id),
diff --git a/src/main/java/com/free_open_university/backend/bean/Book.java b/src/main/java/com/free_open_university/backend/bean/Book.java
index c224bd1..3cf2668 100644
--- a/src/main/java/com/free_open_university/backend/bean/Book.java
+++ b/src/main/java/com/free_open_university/backend/bean/Book.java
@@ -24,7 +24,7 @@ public class Book {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     @Column(name = "book_id")
-    private int id;
+    private Long id;
 
     @Column(name = "title")
     private String title;
@@ -50,11 +50,11 @@ public class Book {
     
     // private Category categoryList;
 
-    public int getId() {
+    public Long getId() {
         return id;
     }
 
-    public void setId(int id) {
+    public void setId(Long id) {
         this.id = id;
     }
 
diff --git a/src/main/java/com/free_open_university/backend/bean/BookCategory.java b/src/main/java/com/free_open_university/backend/bean/BookCategory.java
new file mode 100644
index 0000000..885c5d8
--- /dev/null
+++ b/src/main/java/com/free_open_university/backend/bean/BookCategory.java
@@ -0,0 +1,49 @@
+package com.free_open_university.backend.bean;
+
+import javax.persistence.*;
+import java.util.Set;
+
+
+@Entity
+@Table(name = "BookCategory")
+public class BookCategory {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "bookcategory_id")
+    private Long bookcategory_id;
+
+    @Column(name = "category_id")
+    private Long category_id;
+    @Column(name = "book_id")
+    private Long book_id;
+
+    public Long getBookCategoryId() {
+        return bookcategory_id;
+    }
+
+    public void setBookCategoryId(Long bookcategory_id) {
+        this.bookcategory_id = bookcategory_id;
+    }
+
+    public Long getCategoryId() {
+        return category_id;
+    }
+
+    public void setCategoryId(Long category_id) {
+        this.category_id = category_id;
+    }
+
+    public Long getBookId() {
+        return book_id;
+    }
+
+    public void getBookId(Long book_id) {
+        this.book_id = book_id;
+    }
+
+//    @Override
+//    public String toString() {
+//        return "BookCategory [category_id=" + category_id + ", book_id=" + book_id + "]";
+//    }
+}
diff --git a/src/main/java/com/free_open_university/backend/bean/Category.java b/src/main/java/com/free_open_university/backend/bean/Category.java
index ec06359..db64454 100644
--- a/src/main/java/com/free_open_university/backend/bean/Category.java
+++ b/src/main/java/com/free_open_university/backend/bean/Category.java
@@ -18,12 +18,12 @@ public class Category {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     @Column(name = "category_id")
-    private int id;
+    private Long id;
 
     @Column(name = "name")
     private String name;
     @Column(name = "image_id")
-    private long imageId;
+    private Long imageId;
 
     @ManyToMany(cascade = CascadeType.ALL)
     @JoinTable (
@@ -33,11 +33,11 @@ public class Category {
         )
     private Set<Book> books;
     
-    public int getId() { 
+    public Long getId() {
         return id; 
     }
 
-    public void setId(int id) {
+    public void setId(Long id) {
         this.id = id;
     }
 
@@ -49,19 +49,19 @@ public void setName(String name) {
         this.name = name;
     }
 
-    public Set<Book> getBooks() {
-        return books;
-    }
-
-    public void setBooks(Set<Book> books) {
-        this.books = books;
-    }
+//    public Set<Book> getBooks() {
+//        return books;
+//    }
+//
+//    public void setBooks(Set<Book> books) {
+//        this.books = books;
+//    }
 
-    public long getImageId() {
+    public Long getImageId() {
         return imageId;
     }
 
-    public void setImageId(long imageId) {
+    public void setImageId(Long imageId) {
         this.imageId = imageId;
     }
 }
diff --git a/src/main/java/com/free_open_university/backend/bean/ExeuteShellProcessBuilder.java b/src/main/java/com/free_open_university/backend/bean/ExeuteShellProcessBuilder.java
new file mode 100644
index 0000000..e3d2b0e
--- /dev/null
+++ b/src/main/java/com/free_open_university/backend/bean/ExeuteShellProcessBuilder.java
@@ -0,0 +1,34 @@
+package com.free_open_university.backend.bean;
+
+import java.io.File;
+import java.io.IOException;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.List;
+import java.util.Map;
+
+public class ExeuteShellProcessBuilder {
+
+    public static void main(String[] args) {
+        String[] cmd = new String[] {"src/main/resources/hello.sh"};
+        ProcessBuilder pb = new ProcessBuilder(cmd);
+        try {
+            File log = new File("src/main/resources/log.txt");
+            pb.redirectErrorStream(true);
+            pb.redirectOutput(ProcessBuilder.Redirect.appendTo(log));
+            Process p = pb.start();
+            BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
+            String s = null;
+            while ((s = reader.readLine()) != null) {
+                System.out.println(s);
+            }
+        } catch (IOException e) {
+            // TODO auto-generated catch block
+            e.printStackTrace();
+        }
+    }
+}
+//"src/main/resources/hello.py", "src/main/resources/log.txt"
+//"/home/taniya/Projects/external/openu/openu_back/website-backend/src/main/resources/hello.py"
\ No newline at end of file
diff --git a/src/main/java/com/free_open_university/backend/controller/BookCategoryController.java b/src/main/java/com/free_open_university/backend/controller/BookCategoryController.java
new file mode 100644
index 0000000..e4f5201
--- /dev/null
+++ b/src/main/java/com/free_open_university/backend/controller/BookCategoryController.java
@@ -0,0 +1,52 @@
+package com.free_open_university.backend.controller;
+
+import com.free_open_university.backend.bean.Book;
+import com.free_open_university.backend.bean.BookCategory;
+import com.free_open_university.backend.bean.Category;
+import com.free_open_university.backend.dao.BookCategoryRepository;
+import com.free_open_university.backend.service.BookCategoryService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+
+@RestController
+@RequestMapping("/bookcategory")
+public class BookCategoryController {
+
+    @Autowired
+    BookCategoryRepository bookCategoryRepository;
+    BookCategoryService bookCategoryService;
+
+
+    @GetMapping //("/bookcategory")
+    public List<BookCategory> getAllBookCategories()
+    {
+        return bookCategoryRepository.findAll();
+    }
+
+//    @GetMapping
+//    public List<BookCategory> getAllBookCategories(
+//            @RequestParam(value = "category_id", required = false) Long category_id) {
+//        if (category_id != null) {
+//            return bookCategoryService.getBooksByCategories(category_id);
+//        } else {
+////            return bookCategoryService.getAllBookCategories();
+//            return bookCategoryRepository.findAll();
+//        }
+
+////        This won't work because it has to be /bookcategory/{bookcategory_id}
+//        @GetMapping("/bookcategory/{category_id}")
+//    public List<BookCategory> findByIds(@PathVariable () List<Long> category_id) {
+//        return bookCategoryRepository.findAllById(category_id);
+//    }
+
+
+}
+
+
diff --git a/src/main/java/com/free_open_university/backend/controller/BookController.java b/src/main/java/com/free_open_university/backend/controller/BookController.java
index 5e93107..c8959d0 100644
--- a/src/main/java/com/free_open_university/backend/controller/BookController.java
+++ b/src/main/java/com/free_open_university/backend/controller/BookController.java
@@ -2,8 +2,10 @@
 
 import com.free_open_university.backend.bean.Book;
 import com.free_open_university.backend.http.Response;
+import com.free_open_university.backend.repositories.BookRepository;
 import com.free_open_university.backend.service.BookService;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
@@ -15,6 +17,7 @@ public class BookController {
 
     @Autowired
     BookService bookService;
+    BookRepository bookRepository;
 
 /*    @GetMapping // todo: need another path
     public Book getBookByTitle(@RequestParam(value = "title") String title) {
@@ -42,21 +45,51 @@ public List<Book> getBookId(
         // }
     }
 
-    @PostMapping
-    public Response addBook(@RequestBody  Book newBook) {
-        return bookService.addBook(newBook);
+
+    @PostMapping("/addBook")
+//    @ResponseStatus(HttpStatus.ACCEPTED)
+    private Long addBook(@RequestBody Book book)
+
+    {
+        bookService.saveOrUpdate(book);
+        return book.getId();
     }
 
-    @PostMapping("/batch_upload")
-    public Response addBookBatch(@RequestBody Set<Book> books) {
-        Response response = new Response();
-        for (Book book : books) {
-            response = bookService.addBook(book);
-            if(!response.isSuccess()) {
-                return response;
-            }
-        }
-        return new Response(true,200,"books added");
+    @PostMapping("/addBooks")
+    public List<Book> saveAllBook(@RequestBody List<Book> bookList) {
+        return (List<Book>) bookService.saveAllBook(bookList);
+    }
+
+    @DeleteMapping("/deleteBook/{book_id}")
+    private void deleteBook(@PathVariable("book_id") Long id)
+    {
+        bookService.delete(id);
+    }
+
+//    @DeleteMapping("/deleteBooks")
+//    public String deleteInBatch(@RequestBody List<Book> bookList) {
+//        bookService.deleteInBatch(bookList);
+//        return "All Students deleted successfully";
+//    }
+
+    @PutMapping("/updateBook")
+    private Book updateBook(@RequestBody Book book)
+    {
+        bookService.saveOrUpdate(book);
+        return book;
     }
 
 }
+
+
+//    @PostMapping("/batch_upload")
+//    public Response addBookBatch(@RequestBody Set<Book> books) {
+//        Response response = new Response();
+//        for (Book book : books) {
+//            response = bookService.addBook(book);
+//            if(!response.isSuccess()) {
+//                return response;
+//            }
+//        }
+//        return new Response(true,200,"books added");
+//    }
diff --git a/src/main/java/com/free_open_university/backend/controller/CategoryController.java b/src/main/java/com/free_open_university/backend/controller/CategoryController.java
index 5fa5d55..48e620c 100644
--- a/src/main/java/com/free_open_university/backend/controller/CategoryController.java
+++ b/src/main/java/com/free_open_university/backend/controller/CategoryController.java
@@ -1,24 +1,56 @@
 package com.free_open_university.backend.controller;
 
+import com.free_open_university.backend.bean.Book;
+import com.free_open_university.backend.bean.BookCategory;
 import com.free_open_university.backend.bean.Category;
+import com.free_open_university.backend.repositories.BookRepository;
+import com.free_open_university.backend.repositories.CategoryRepository;
 import com.free_open_university.backend.service.CategoryService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 
 @RestController
-@RequestMapping("/category")
+//@RequestMapping("/category")
 public class CategoryController {
 
     @Autowired
-    CategoryService categoryService;
+//    CategoryService categoryService;
+    CategoryRepository categoryRepository;
+    BookRepository bookRepository;
 
-    @GetMapping
-    public List<Category> getAllCategories() {
-        return categoryService.getAllCategories();
+//    @GetMapping
+//    public List<Category> getAllCategories() {
+//        return categoryService.getAllCategories();
+//    }
+
+    @GetMapping("/category")
+    public List<Category> getAllCategories()
+    {
+        return categoryRepository.findAll();
+    }
+
+    @GetMapping("/category/{id}")
+    public Optional<Category> getCategoryById(@PathVariable(value="id") Long id)
+    {
+        return categoryRepository.findById(id);
     }
+
+//    @GetMapping("/category/{id}/books")
+//    public List<Category> getBooksbyCategory(@PathVariable(value="books") Long books)
+//    {
+//        return categoryRepository.findBooksByCategory(books);
+//    }
+
+//    @GetMapping("/category/{id}/books")
+//    public List<BookCategory> getBooksbyCategory(@PathVariable(value="books") Long book_id)
+//    {
+//        return categoryRepository.findBooksByCategory(book_id);
+//    }
 }
diff --git a/src/main/java/com/free_open_university/backend/dao/BookCategoryRepository.java b/src/main/java/com/free_open_university/backend/dao/BookCategoryRepository.java
new file mode 100644
index 0000000..f8e8809
--- /dev/null
+++ b/src/main/java/com/free_open_university/backend/dao/BookCategoryRepository.java
@@ -0,0 +1,27 @@
+package com.free_open_university.backend.dao;
+
+import com.free_open_university.backend.bean.Book;
+import com.free_open_university.backend.bean.BookCategory;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface BookCategoryRepository extends JpaRepository<BookCategory, Long> {
+
+//    List<BookCategory> findBooksByBookCategory(Long category_id);
+//    List<BookCategory> findAllById(Long category_id);
+
+
+
+//    @Query("SELECT new com.roytuts.spring.data.jpa.left.right.inner.cross.join.dto.JoinDto(BookCategory.category_id, BookCategory.book_id, Book.title "
+//            + "FROM Sale s INNER JOIN s.food f INNER JOIN f.company c")
+//    List<JoinDto> fetchDataInnerJoin();
+//
+//    SELECT BookCategory.category_id, BookCategory.book_id, Book.title FROM BookCategory INNER JOIN Book ON BookCategory.book_id=Book.book_id;
+
+//    List<BookCategory> findbyCategory(Long category_id);
+
+
+}
diff --git a/src/main/java/com/free_open_university/backend/repositories/BookRepository.java b/src/main/java/com/free_open_university/backend/repositories/BookRepository.java
index 4ddb0eb..2a3ae20 100644
--- a/src/main/java/com/free_open_university/backend/repositories/BookRepository.java
+++ b/src/main/java/com/free_open_university/backend/repositories/BookRepository.java
@@ -5,11 +5,12 @@
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
+import java.io.Serializable;
 import java.util.List;
 import java.util.Set;
 import java.util.Optional;
 
-public interface BookRepository extends JpaRepository<Book, Integer> {
+public interface BookRepository extends JpaRepository<Book, Serializable> {
 
     Optional<Book> findByTitle(String title);
 
diff --git a/src/main/java/com/free_open_university/backend/repositories/CategoryRepository.java b/src/main/java/com/free_open_university/backend/repositories/CategoryRepository.java
index 855b3ed..d7a0941 100644
--- a/src/main/java/com/free_open_university/backend/repositories/CategoryRepository.java
+++ b/src/main/java/com/free_open_university/backend/repositories/CategoryRepository.java
@@ -1,10 +1,17 @@
 package com.free_open_university.backend.repositories;
 
+//import com.free_open_university.backend.bean.Book;
+import com.free_open_university.backend.bean.BookCategory;
 import com.free_open_university.backend.bean.Category;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 
-public interface CategoryRepository extends JpaRepository<Category, Integer> {
+public interface CategoryRepository extends JpaRepository<Category, Long> {
+
+//    List<Category> findBooksByCategory(Long book_id);
+
 }
+
diff --git a/src/main/java/com/free_open_university/backend/service/BookCategoryService.java b/src/main/java/com/free_open_university/backend/service/BookCategoryService.java
new file mode 100644
index 0000000..44261c9
--- /dev/null
+++ b/src/main/java/com/free_open_university/backend/service/BookCategoryService.java
@@ -0,0 +1,29 @@
+package com.free_open_university.backend.service;
+
+import com.free_open_university.backend.bean.Book;
+import com.free_open_university.backend.bean.BookCategory;
+import com.free_open_university.backend.bean.Category;
+import com.free_open_university.backend.dao.BookCategoryRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class BookCategoryService {
+
+    @Autowired
+    BookCategoryRepository bookCategoryRepository;
+
+//    public List<BookCategory> getAllBookCategories() {
+//        return bookCategoryRepository.findAll();
+//    }
+
+//    public List<BookCategory> getBooksByCategories(Long category_id) {
+//        return bookCategoryRepository.findbyCategory(category_id);
+//    }
+
+//    public List<BookCategory> getBooksbyCategoryId(Long category_id) { return bookCategoryRepository.findAllById(category_id); }
+
+}
diff --git a/src/main/java/com/free_open_university/backend/service/BookService.java b/src/main/java/com/free_open_university/backend/service/BookService.java
index 542b9f6..08a5e93 100644
--- a/src/main/java/com/free_open_university/backend/service/BookService.java
+++ b/src/main/java/com/free_open_university/backend/service/BookService.java
@@ -26,14 +26,26 @@ public Optional<Book> getBookByTitle(String title) {
         return bookRepository.findByTitle(title);
     }
 
-    @Transactional
-    public Response addBook(Book newBook) {
-        try{
-            bookRepository.save(newBook);
-            return new Response(true, "book added");
-        } catch (Exception e) {
-            e.printStackTrace();
-            return new Response(false, "book not added");
-        }
+    public void saveOrUpdate(Book book)
+    {
+        bookRepository.save(book);
     }
+
+    public List<Book> saveAllBook(List<Book> bookList) { return  bookRepository.saveAll(bookList); }
+
+    public void delete(Long id) { bookRepository.deleteById(id); }
+
+    public void deleteInBatch(List<Book> bookList) { bookRepository.deleteInBatch(bookList);
+    }
+
+//    @Transactional
+//    public Response addBook(Book newBook) {
+//        try{
+//            bookRepository.save(newBook);
+//            return new Response(true, "book added");
+//        } catch (Exception e) {
+//            e.printStackTrace();
+//            return new Response(false, "book not added");
+//        }
+//    }
 }
diff --git a/src/main/java/com/free_open_university/backend/service/CategoryService.java b/src/main/java/com/free_open_university/backend/service/CategoryService.java
index 2152d1a..8314194 100644
--- a/src/main/java/com/free_open_university/backend/service/CategoryService.java
+++ b/src/main/java/com/free_open_university/backend/service/CategoryService.java
@@ -1,11 +1,14 @@
 package com.free_open_university.backend.service;
 
+import com.free_open_university.backend.bean.Book;
+import com.free_open_university.backend.bean.BookCategory;
 import com.free_open_university.backend.bean.Category;
 import com.free_open_university.backend.repositories.CategoryRepository;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 
 @Service
@@ -18,4 +21,7 @@ public List<Category> getAllCategories() {
         return categoryRepository.findAll();
     }
 
+//    public List<Category> getBooksbyCategory(Long books) { return categoryRepository.findBooksByCategory(books); }
+
+//    public List<BookCategory> getBooksbyCategory(Long book_id) { return categoryRepository.findBooksByCategory(book_id); }
 }
\ No newline at end of file
diff --git a/src/main/resources/hello.py b/src/main/resources/hello.py
new file mode 100755
index 0000000..c69cd28
--- /dev/null
+++ b/src/main/resources/hello.py
@@ -0,0 +1,4 @@
+print("Hello World")
+
+x = 5 + 2
+print(x)
diff --git a/src/main/resources/hello.sh b/src/main/resources/hello.sh
new file mode 100755
index 0000000..10fff19
--- /dev/null
+++ b/src/main/resources/hello.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+echo "hello.sh has been executed by java"
+echo "testing again"
+python3 /home/taniya/Projects/external/openu/openu_back/website-backend/src/main/resources/hello.py
\ No newline at end of file
diff --git a/src/main/resources/log.txt b/src/main/resources/log.txt
new file mode 100644
index 0000000..a964f86
--- /dev/null
+++ b/src/main/resources/log.txt
@@ -0,0 +1,28 @@
+hello.sh has been executed by java
+testing again
+src/main/resources/hello.sh: line 5: python: command not found
+hello.sh has been executed by java
+testing again
+src/main/resources/hello.sh: line 5: python: command not found
+hello.sh has been executed by java
+testing again
+src/main/resources/hello.sh: line 5: python: command not found
+hello.sh has been executed by java
+testing again
+src/main/resources/hello.sh: line 5: python: command not found
+hello.sh has been executed by java
+testing again
+Hello World
+7
+hello.sh has been executed by java
+testing again
+Hello World
+7
+hello.sh has been executed by java
+testing again
+Hello World
+7
+hello.sh has been executed by java
+testing again
+Hello World
+7