Is there a class called Abstract Rest Application in Java?

JDBC:-
Java Database Connectivity which is a specification for developing database applications with Java programming language.

The JDBC had several drawbacks
For example:
1. Boilerplate code (tedious code to work with data access Layer)
2. SQL exception-> Checked Exception so mandatorily needs to be handled.
3. Non portability because SQL codes are within the Java program; we can’t supply the SQL queries from outside the java program and also the SQL queries are database-specific.
4. Dialect issue in case of change of database
5. JDBC API can’t transfer the java objects directly
6. If the table structure is modified after the construction of Jdbc code then we must modify the sql queries again which is time consuming and burden for the java developer.
7. Manual resource clean up
8. Transactions must be handled manually

In order to overcome these problems spring JDBC was released.
It is an abstraction layer on top of jdbc technology.
Spring JDBC provides several methods to write the queries directly, so it saves a lot of work and time.
Spring JDBC however internally uses JDBC api only.

ORM:- (Object Relational Mapping) (To save the state of Java Objects into data base)
* It is a technique for converting/mapping data between java Objects and relational database
* Responsible for mapping the Domain Objects to Relational Model and vice versa

Why ORM?

Technical Differences between java Object and Relational Object
1. Granularity issue
2. Inheritance issue
3. Data Comparison issue
4. Data traversal difference

To overcome these technical problems, ORM was introduced.

They are several ORM tools available.

1. Hibernate
2. EclipseLink
3. OpenJPA
4. TopLink
5. Ibatis(MyBatis)

Which are all the implementations/JPA Providers/JPA vendors.

JPA (Java Persistence API) is a standard/specification/guidelines which are implemented/followed by all those ORM tools.

For easy understanding,
JPA is like an interface provided by the JCP( Java Community Process or Sun Microsystems (Oracle)) and ORM tools are the implementation classes

JPA facilities easy portability and migration.
With JPA, we can easily migrate from one JPA implementation to another JPA implementation.(Portability) (Loose Coupling)

Among all those JPA vendors, Hibernate (org.hibernate) is widely used because
1. It’s an Open source, publicly available without any cost and lightweight
2. Takes care of Auto Table Creation, Auto Primary Key generation
3. Provides Caching (Dual Layer caching) (first level and second level caching)
4. Supports Associations(mapping), inheritance, Joins
5. Provides Eager and lazy loading
6. Pagination support
7. Exception Handling is not mandatory.
8. Scalability
9. HQL (HIbernate Query Language) -> Database Independent Language
10. Transaction support
11. NativeSQL (we can write our SQL directly)
12. Locking -> Pessimistic and Optimistic Locking
13. Connection pooling mechanism for improving connection reusability
14. *Criteria API* which auto-generates *tuned Queries*

ORM tools however use the JDBC API internally

Hi all,I need help in java Spring Async method can anybody help.??

I am facing a problem.
My war is deployed on tocmat on a server.

I am getting respond when hitting through postman

But when i hit from Android app, request not even reaching server, is it something with tomcat. Pls help .

I have another application running on same ip but diff port, that port is working fine.

If so then it should throw some error on cosnisle

I’m getting a problem in pom.xml saying that NON resolvable parent POM.
Someone help me please

I think it just times out …in Android it used volley /JSON object request

Or parent pom not resolved ..try just running mvn clean install . Sometimes eclipse will show this kind of weird error

Still no help

Do a telnet from ur system n chk the port and ip is reachable or nt

I am facing a problem.
My war is deployed on tocmat on a server.

I am getting respond when hitting through postman

But when i hit from Android app, request not even reaching server, is it something with tomcat. Pls help .

I have another application running on same ip but diff port, that port is working fine.

what is your problem