Add BookRepository.java

src/main/java/com/ankurm/sdjpa4demo/repo/BookRepository.java

@@ -0,0 +1,16 @@
+package com.ankurm.sdjpa4demo.repo;
+
+import com.ankurm.sdjpa4demo.domain.Book;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.math.BigDecimal;
+import java.util.List;
+
+public interface BookRepository extends JpaRepository<Book, Long> {
+
+    List<Book> findByPriceGreaterThanEqual(BigDecimal price);
+
+    // Single-result derived query that can match MORE than one row on bad data:
+    // demonstrates IncorrectResultSizeDataAccessException (the "non-unique" edge case).
+    Book findByPrice(BigDecimal price);
+}