Hibernate Configuration

Hibernate configuration properties :-

hibernate.dialect : allows Hibernate to generate SQL optimized for a particular relational database.

hibernate.show_sql : Write all SQL statements to console.

hibernate.format_sql : Pretty print the SQL in the log and console.

hibernate.connection.autocommit : Enables autocommit for JDBC pooled connections (it is not recommended)

Hibernate introduction

Hibernate ORM (Hibernate in short) is an object-relational mapping framework for the Java language, providing a framework for mapping an object-oriented domain model to a traditional relational database. Hibernate solves object-relational impedance mismatch problems by replacing direct persistence-related database accesses with high-level object handling functions.

PostgreSQL Basic Queries

SCHEMA

- Create Schema 

CREATE SCHEMA schema_name;

- Rename Schema

ALTER SCHEMA schema_name RENAME to schema_name_new

- Drop Schema

DROP SCHEMA schema_name;

Spring mvc example with maven using eclipse

Spring Mvc Example 

We are going to create a spring mvc base example with maven in eclipce.

In this example we will print a message "Hello World" on screen and will handle same common errors like 404 (URL not found) or 500 (internal server error).

1. Click on File -> New -> other and select Maven Project

Maven introduction

Maven introduction :-

Maven is a build management tool from the Apache Software Foundation. Maven allows a project to build using its project object model (POM) and a set of plugins that are shared by all projects using Maven. It is used for projects build, dependency and documentation.

Maven’s Objectives -

1. Making the build process easy
2. Providing a uniform build system
3. Providing quality project information
4. Providing guidelines for best practices development
5. Allowing transparent migration to new features

Java Object cloning

Object cloning means creating a copy of original object with different reference.

Object cloning can be of two types - Shallow cloning and Deep cloning.

Shallow cloning :-

Java Object Class already have a clone method. By default this clone method do shallow cloning.

As per java docs

Object clone method Creates and returns a copy of this object.
The precise meaning of "copy" may depend on the class of the object.
The general intent is that, for any object x, the expression:

1) x.clone() != x will be true
2) x.clone().getClass() == x.getClass() will be true, but these are not absolute requirements.
3) x.clone().equals(x) will be true, this is not an absolute requirement.

Select drop-down list in jquery

  Get selected value using class :-

$(".drop_down_class").val();

Get selected value using Id :-

$("#drop_down_id").val();

Get text of selected value :-

$("#drop_down_id").text();

How to sort a hashset

Covert set into list than sort it using collection utill

A HashSet does not guarantee any order of its elements

Set unSortedHashSet = new HashSet();

List sortedList = new ArrayList(unSortedHashSet);

Collections.sort(sortedList);