Merge remote-tracking branch 'origin/main' into main

src/main/java/feature/Book.java

@@ -0,0 +1,35 @@
+package feature;
+
+public class Book {
+    private String title;
+    private String author;
+    private int pages;
+
+    public Book(String title, String author, int pages) {
+        this.title = title;
+        this.author = author;
+        this.pages = pages;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public int getPages() {
+        return pages;
+    }
+
+    @Override
+    public String toString() {
+        return "Book{" +
+                "title='" + title + '\'' +
+                ", author='" + author + '\'' +
+                ", pages=" + pages +
+                '}';
+    }
+    
+}

src/main/java/feature/BookDemo.java

@@ -0,0 +1,15 @@
+package feature;
+
+/**
+ * create singleton using enum
+ */
+public class BookDemo {
+    public static void main(String[] args) {
+        Book book = new Book("Java Programming", "John Doe", 300);
+        System.out.println(book);
+
+        // Using the singleton pattern
+        BookEnum.INSTANCE.setBook(book);
+        System.out.println(BookEnum.INSTANCE.getBook());
+    }
+}

src/main/java/feature/BookEnum.java

@@ -0,0 +1,14 @@
+package feature;
+
+public enum BookEnum {
+    INSTANCE;
+
+    private Book book;
+    
+    public Book getBook() {
+        return book;
+    }
+    public void setBook(Book book) {
+        this.book = book;
+    }
+}