Spring Boot

Bean Validation checks user input against rules written as annotations on the Java fields, such as @NotBlank, @Email and @Min.It is used so bad data (empty names, wrong emails, invalid mobile numbers) is rejected before it reaches your logic or the database.You put the rules on the model, add @Valid on the controller parameter, and […]

Form data binding automatically copies the values typed into an HTML form into the fields of a Java object.It is used so you don’t read each field by hand with request.getParameter(). Spring creates the object, fills it, and converts text to numbers and dates.In Spring MVC it works through @ModelAttribute on the controller and th:object

DatabaseMetaData is a JDBC interface used to obtain information about the database, JDBC driver, tables, columns, and supported database features. It is obtained from a Connection object using the getMetaData() method. Using DatabaseMetaData, a Java program can dynamically inspect database information without directly querying system tables. This is useful for database administration, debugging, database migration

This topic combines three features in one API: search narrows the records, sorting orders them, and pagination returns them a page at a time.It is used for real listing screens, such as an admin table with a search box, sortable columns and page buttons.Spring Data handles all three in one repository method, with a Pageable

Search finds records by matching keywords against fields such as name, email or department, instead of returning the whole table.It is used so users can quickly find the data they need, even with partial words or different upper/lower case.Spring Data supports it through derived query methods (findByNameContainingIgnoreCase) and custom @Query JPQL for more complex searches.The

Sorting orders database results by one or more fields, such as name, age or registration date, in ascending or descending order.It is used so users can see data in a meaningful order (A–Z, newest first, youngest first) without sorting it in Java code.Spring Data provides it through the Sort class, and a Sort can also

Pagination splits a large database result into small pages, so the API returns only a few records at a time instead of the whole table. It is used to cut response time, memory usage and network load, and to make lists easier to browse. Spring Data provides it through the Pageable interface, with PageRequest as

Pagination, Sorting and Searching are essential data retrieval techniques used in web applications and REST APIs to handle large datasets efficiently. Instead of loading thousands of records into memory at once—which degrades performance, consumes excessive network bandwidth, and slows down client applications—these techniques allow clients to retrieve data incrementally, in a specific order, and filtered

A composite key is a primary key made of two or more fields that together identify a record uniquely, such as (student_id, course_id). It is used when no single column identifies a row, most often in join tables like enrollments, where the same student can appear many times and the same course can appear many

Many-to-Many mapping links records so that one record on either side can be associated with many records on the other side (one student takes many courses, one course has many students). It is used because a relational database cannot store this directly in two tables, so JPA creates a third table, called a join table,