How to load Environment specific properties using Spring PropertyPlaceholderConfigurer

This post will explain how to load environment specific[DEV,SIT,UAT,PROD] properties from the single properties file

Step 1: Create simple java project using eclipse
Step 2: Create a abstract class , with under package - com.javaguru.property, i have created with name - PropertyClient.java

package com.javaguru.property;

public abstract class PropertyClient {

 
 protected String hostName;
 protected String userId;
 protected String password;
 
 
 
 public PropertyClient(String hostName, String userId, String password) {
  super();
  this.hostName = hostName;
  this.userId = userId;
  this.password = password;
  
 }
 
 public PropertyClient(){
  
 }
 
 public String getHostName() {
  return hostName;
 }
 public void setHostName(String hostName) {
  this.hostName = hostName;
 }
 public String getUserId() {
  return userId;
 }
 public void setUserId(String userId) {
  this.userId = userId;
 }
 public String getPassword() {
  return password;
 }
 public void setPassword(String password) {
  this.password = password;
 }
 
 //common methods related to functionality
}
   

Step 3: Create implementation class.

package com.javaguru.property;

public class PropertyClientImpl extends PropertyClient{

 
 public PropertyClientImpl(String hostName, String userId, String password) {
  super(hostName, userId, password);
 }
 public PropertyClientImpl(){
  super();
 }
 //Implementation of abstract methods
}

Step 4: Create property file name called - application.properties under src folder

[DEV]
ftp.dev.hostname=dev.com
ftp.dev.username=user
ftp.dev.password=pass

[SIT]
ftp.sit.hostname=sit.net
ftp.sit.username=user
ftp.sit.password=pass

[UAT]
ftp.uat.hostname=uat.net
ftp.uat.username=user
ftp.uat.password=pass

[PROD]
ftp.prod.hostname=prod.net
ftp.prod.username=user
ftp.prod.password=pass

Step 5: Create applicationContext.xml under src- folder

 

 
   
  application.properties
  
 


    
    
    

Step 6: Create Test class with name - TestEnvSpecificProperty.java- or call the code which ever place you need to load the properties

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.javaguru.property.PropertyClient;
import com.javaguru.property.PropertyClientImpl;
/**
 * 
 * @author siva
 *
 */
public class TestEnvSpecificProperty {

 public static void main(String[] args) {
  //Set which environment properties we need to load.
  System.setProperty("env","dev");
  //load the applicationContext.xml file
  ApplicationContext context =  new ClassPathXmlApplicationContext("applicationContext.xml");
  PropertyClient propertyClient= (PropertyClientImpl)context.getBean("propertyClient");
  //print property details
   System.out.println("Host Name: ["+propertyClient.getHostName()+"]");
   System.out.println("User ID: ["+propertyClient.getUserId()+"]");
   System.out.println("Password: ["+propertyClient.getPassword()+"]");
  
 }
}

Step 7: Output would be like below, if you mention System property as dev

Host Name: [dev.com]
User ID: [user]
Password: [pass]

Step 8: Required jars

commons-codec-1.3.jar
commons-collections-3.2.jar
commons-logging-1.1.1.jar
commons-net-3.3.jar
spring-asm-3.0.5.RELEASE.jar
spring-beans-3.0.4.RELEASE.jar
spring-context-3.0.5.RELEASE.jar
spring-core-3.0.4.RELEASE.jar
spring-expression-3.2.1.release.jar

How to check given interger value is palindrome or not using java

This post will explain you about, given integer palindrome or not.
ex: 121 or 1441 is palindrome- if we write reverse also it should be same

public class PalindromeTest {
 
 public static  boolean isPalindrome(int number){
  boolean isPolindrome = false;
  int palindrome = number;
  int reverseValue = 0;
  while(palindrome !=0){
   int reminder = palindrome % 10;
   reverseValue = reverseValue * 10 + reminder;
   palindrome = palindrome/10;
  }
   if(number==reverseValue){
    isPolindrome = true;
   }
  return isPolindrome;
  
 }
 public static void main(String[] args) {
  System.out.println("Given number is palindrome["+PalindromeTest.isPalindrome(121)+"]");
 }

}

output:

Given number is palindrome[true]

How to print fibonacci series values using java

This post will explain you about how to write fibonacci program for given 10 integer value using java

public class Fibonacci {
 
 public static void main(String[] args) {
  
  int febonacci[] = new int[10];
  febonacci[0]=0;
  febonacci[1]=1;
  for (int i = 2; i < febonacci.length; i++) {
   febonacci[i] = febonacci[i-1]+febonacci[i-2];
   
  }
  for (int i = 0; i < febonacci.length; i++) {
   System.out.print(febonacci[i]+",");
  }
  
  
 }

output:

0,1,1,2,3,5,8,13,21,34

Java interview questions

1.How ArrayList internally works or What will happen if we initialized arraylist size as 10 and tried to add 11th element to arrayList?

Ans: ArrayList uses object[] internally.
ArrayList default size is - 10
If we initialize default size as 10 for arraylist.
Now we are trying add 11th element to ArrayList.
Then it will doubled the size(now size is 20).
Copy previous elements(old array) to new arraylist(new array)
Add the new element(11th element) in newly created array.
Arraylist internally uses array datastructure.