How to pass JSON Object string or JSONArray string from javascript to spring controller

March 14, 2013 13 comments

We usually send primitive data to spring controller by using @RequestParam annotation. But how to pass whole JSONObject string or JSONArray string to spring controller directly.

For that we have to include below jar files in buildpath

  1. jackson-core-asl-1.7.3.jar
  2. jackson-mapper-asl-1.7.3.jar

I have created Person pojo which will be mapped with javascript JSONObject exactly, Whatever the identifiers are there in this POJO should be there in Javascript JSON.

public class Person implements Serializable{
private String id;
private String firstName;
private String lastName;
//setters and getters
}

Pojo should implement Serializable interface, as  Jackson will serialize and deserialize to send data between server and client.

Our json data is :
{"persons": [
{
"firstName": "Ramesh",
"id": "id1",
"lastName": "Kotha"
},
{
"firstName": "Sathish",
"id": "id2",
"lastName": "Kotha"
}
]
}

Below is an ajax request from jsp.

$.ajax({
type: 'POST',
dataType: 'json',
contentType:'application/json',
url: "create_persons.htm",
data:JSON.stringify(arr),
success: function(data, textStatus ){
console.log(data);
//alert("success");
},
error: function(xhr, textStatus, errorThrown){
//alert('request failed'+errorThrown);
}
});

Now will see Spring controller Code:

@RequestMapping(value="/create_persons.htm")
public @ResponseBody createPerson(@RequestBody Person[] persons){
//here you can persons array as normal
for(Person person : persons){
System.out.println(person.getId());
}
}

By seeing @RequestBody annontation json data will be converted into Java Person[] and passed to persons array.

Add this in your Configuration file :

<bean id="jacksonMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="jacksonMessageConverter"/>
</list>
</property>

That’s it, now if you pass json string to the spring controller, it will be converted into java POJO.

Categories: Java, Spring

How to solve org.apache.lucene.index.CorruptIndexException?

February 19, 2013 Leave a comment

If solr server stops while indexing is going on, we may get org.apache.lucene.index.CorruptIndexException error.

To solve this we have to use org.apache.lucene.index.CheckIndex class. We have to run this class to fix the corrupted indexes in solr.

1.  First take back up your indexed data
2.  Go to the directory where lucene-core.3.6.1.jar is there

3. then run this command
java -cp lucene-core-3.1.0.jar -ea:org.apache.lucene… org.apache.lucene.index.CheckIndex “your indexed directory path” –fix
in my case it is
java -cp lucene-core-3.1.0.jar -ea:org.apache.lucene… org.apache.lucene.index.CheckIndex “C:\Program Files\gisgraphy-3.0-beta2\solr\data\index” –fix

corruptedindex

As there are no corrupted indexes in my case it says “No problems were detected with this index”

If there are any corrupted indexes are there then those will be fixed with this command and solr will be working fine.

Categories: Java, solr

Spring AOP explained in simple terms

February 2, 2013 3 comments

Aspect Oriented Programming:

Developer has to concentrate on business logic, Cross cutting functionalities like Transactions, Logging, Data Access Logic should be taken care by container.

This principle is called AOP.

Until I have used AOP, I didn’t recognize its worth:

1.       Let’s explore the non AOP architecture

package com.java2practice.aop;
import java.math.BigDecimal;

public class Account {
BigDecimal currentAmount = new BigDecimal("5000");

public BigDecimal withdraw(BigDecimal withdrawlAmount){
if(withdrawlAmount.compareTo(currentAmount) < 0 )
     return currentAmount.subtract(withdrawlAmount);
else
     throw new FundsNotSufficientException();
 }
}

Do we have any problem with above withdraw method, if we observe closely?

First we should use logging. Otherwise resolving the errors would be a big problem.

For that we will change the above method accordingly

import java.math.BigDecimal;
import org.apache.log4j.Logger;

public class Account {
Logger logger = Logger.getLogger(Account.class);
BigDecimal currentAmount = new BigDecimal("5000");

public BigDecimal withdraw(BigDecimal withdrawlAmount){
    logger.info("withdraw method started");
    if(withdrawlAmount.compareTo(currentAmount) < 0 ){
       return currentAmount.subtract(withdrawlAmount);
   }
   else{
     throw new FundsNotSufficientException();
    }
    logger.info("withdraw method successfully completed");
  }
}

Second there is no Transaction started, As withdraw method going update the currentAmount in Database it should be within Transaction so will add transaction.

import java.math.BigDecimal;
import org.apache.log4j.Logger;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class Account {
Logger logger = Logger.getLogger(Account.class);
BigDecimal currentAmount = new BigDecimal("5000");

public BigDecimal withdraw(BigDecimal withdrawlAmount){
   Transaction tx = null;
   Session session = getCurrentSession();
   try{
     logger.info("withdraw method started");
     if(withdrawlAmount.compareTo(currentAmount) < 0 ){
        tx = session.beginTransaction();
        currentAmount = currentAmount.subtract(withdrawlAmount);
        tx.commit();
        return currentAmount;
       }
     else{
       tx.rollback();
       logger.debug("FundsNotSufficientException :: withdraw method failed");
       throw new FundsNotSufficientException();
    }
   logger.info("withdraw method successfully completed");
 }catch(Exception ex){
   tx.rollback()
   logger.debug("withdraw method failed");
   }
  }
}

Now we implemented Transactions and logging successfully but what we are doing if any new requirement is coming we are changing the BankAccount class which is against Object Oriented principle.

If we think again there should be data access logic for the Bank Account class then we have to change once again the class to like this:

package com.java2practice.aop;
import java.math.BigDecimal;
import org.apache.log4j.Logger;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class Account {
Logger logger = Logger.getLogger(Account.class);
BigDecimal currentAmount = new BigDecimal("5000");

public BigDecimal withdraw(BigDecimal withdrawlAmount){
    logger.info("withdraw method started");
    Transaction tx = null;
    Session session = getCurrentSession();
    try{
      if(currentUser.isWIthdrawEnabled()){
        if(withdrawlAmount.compareTo(currentAmount) < 0 ){
          tx = session.beginTransaction();
          currentAmount = currentAmount.subtract(withdrawlAmount);
          tx.commit();
          return currentAmount;
        }
      else{
        tx.rollback();
        logger.debug("FundsNotSufficientException :: withdraw method failed");
        throw new FundsNotSufficientException();
       }
     logger.info("withdraw method successfully completed");
     }else {
     logger.info("withdraw method Failed withdrawal is disabled for this user");
   }
  }catch(Exception ex){
    tx.rollback();
    logger.debug("withdraw method failed");
   }
  }
}

Now it looks fine, but in future any new cross cutting functionality comes, we need to change the Bank Account class once again. What if we separate the cross cutting functionalities like Logging, Security, Transaction to outside of the business logic then we can add new cross cutting functionality without touching BankAccount class.

Imagine if the Data access logic changes, we may need to change lot of files. Same with the entire cross cutting functionalities, They should not be coupled with the business logic and should be defined separately. This we can achieve through Spring AOP.

2. Will see the AOP architecture:

For Cross cutting functionality Logging will see the AOP architecture

  1. CustomerDAO.java
package com.java2practice.dao;

public interface CustomerDAO {
   String addCustomer();
   String addCustomerReturnValue()
   void addCustomerThrowException() throws Exception;
   void addCustomerAround(String name);
}
  1. CustomerDAOImpl.java
package com.java2practice.dao.impl;
import com.java2practice.dao.CustomerDAO;

public class CustomerDAOImpl implements CustomerDAO {
  public String addCustomer(){
     System.out.println("addCustomer() is running ");
     //throw new ArithmeticException();
     return "ramesh";
   }
  public String addCustomerReturnValue(){
     System.out.println("addCustomerReturnValue() is running ");
     return "abc";
  }
  public void addCustomerThrowException() throws Exception {
     System.out.println("addCustomerThrowException() is running ");
     throw new Exception("Generic Error");
   }
  public void addCustomerAround(String name){
    System.out.println("addCustomerAround() is running, args : " + name);
  }
}

Here logging will be implemented by AOP, for that we need to write an Aspect.

  1. LoggingAspect.java
package com.java2practice.aspect;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class LoggingAspect {
  @Before("execution(* com.java2practice.dao.*.*(..))")
  public void logBefore(JoinPoint joinPoint) {
     System.out.println(joinPoint.getSignature().getName()+" is started! from logBefore");
  }
  @After("execution(* com.java2practice.dao.*.*(..))")
  public void logAfter(JoinPoint joinPoint){
    System.out.println(joinPoint.getSignature().getName()+" is completed! from logAfter");
  }
  @AfterThrowing(pointcut = "execution(* com.java2practice.dao.CustomerDAO.*(..))", throwing= "error")
  public void logAround(JoinPoint joinPoint, Object error){
    System.out.println(joinPoint.getSignature().getName()+" after throwing called! from after throwing "+error);
  }
  @AfterReturning(  pointcut = "execution(* com.java2practice.dao.CustomerDAO.addCustomerReturnValue(..))", returning= "result")
  public void afterReturning(JoinPoint joinPoint, Object result){
    System.out.println("after returning called result: "+result);
  }
  @Around("execution(* com.java2practice.dao.CustomerDAO.addCustomerAround(..))")
  public void logAround(ProceedingJoinPoint joinPoint) throws Throwable {
    System.out.println("Around before is running!");
    if(joinPoint.getArgs()[0].equals("ramesh")){
       joinPoint.proceed(); //continue on the intercepted method
       System.out.println("Around after is running!");
     }
    else{
      System.out.println("you dont have permission to call this method");
    }
  }
}
  1. @Aspect annotation will tells the container it is an Aspect
  2. @Before(“execution(* com.java2practice.dao.*.*(..))”) — it will be executed before any method executes  in com.java2.practice.dao package
  3. @After(“execution(* com.java2practice.dao.*.*(..))”) — it will be executed after any method execution in com.java2.practice.dao package
  4. @AfterThrowing(pointcut = “execution(* com.java2practice.dao.CustomerDAO.*(..))”, throwing= “error”) —  It will be executed if any method throws any exception in com.java2practice.dao.CustomerDAO class and the error will be captured in “error”.
  5. @AfterReturning(  pointcut = “execution(* com.java2practice.dao.CustomerDAO.addCustomerReturnValue(..))”, returning= “result”) – it will be executed if com.java2practice.dao.CustomerDAO.addCustomerReturnValue() method returns any value and the returned value will be stored in “result”.
  6. @Around(“execution(* com.java2practice.dao.CustomerDAO.addCustomerAround(..))”) – This is very powerful l aspect, it will be executed before the method execution and after the method execution.  Even we can control the method execution  by joinPoint.proceed()

So now will write spring-config.xml

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">
    <aop:aspectj-autoproxy />
    <bean id="customerDAO" />
    <!-- Aspect -->
    <bean id="logAspect" />
</beans>

Finally will write  Main program to see the power of AOP.

package com.java2practice.aspect;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.java2practice.dao.CustomerDAO;

public class Main {
  public static void main(String[] args)  {
  ApplicationContext context = new ClassPathXmlApplicationContext("spring-config.xml");
  CustomerDAO customer = (CustomerDAO) context.getBean("customerDAO");
  try {
    //customer.addCustomer();
      customer.addCustomerAround("ramesh");
    //customer.addCustomerReturnValue();
    //customer.addCustomerThrowException();
     } catch (Exception e) {
    //e.printStackTrace();
   }
 }
}

Have fun with  AOP.

Categories: Java, Spring

Java Webservice with Axis

WebServices with Apache Axis:

A)     Creating the WebService Server.

  1. Create a java dynamic web project with eclipse    page1
    2.  Create Java Class, this class will contain a method which converts a given string into upper case string, very small method. We will call this method from the webservice client program.

     package com;
    
    public class TestWebService {
    public String getName(String name){
    return name.toUpperCase();
    }
    }
    

3. Righ click on the class select New -> WebServices  -> WebService

page2

4. Click Next -> Next

page3

5. Click on Start Server leave everything as default and click finish

page4

6. Now check http://localhost:8080/WebServiceTest/services/TestWebService?wsdl in browser

It will give you the WSDL file


<wsdl:definitions targetNamespace="http://com"><!--WSDL created by Apache Axis version: 1.4
Built on Apr 22, 2006 (06:55:48 PDT)--><wsdl:types><schema elementFormDefault="qualified" targetNamespace="http://com"><element name="getName"><complexType><sequence><element name="name" type="xsd:string"/></sequence></complexType></element><element name="getNameResponse"><complexType><sequence><element name="getNameReturn" type="xsd:string"/></sequence></complexType></element></schema></wsdl:types><wsdl:message name="getNameRequest"><wsdl:part element="impl:getName" name="parameters">

</wsdl:part></wsdl:message><wsdl:message name="getNameResponse"><wsdl:part element="impl:getNameResponse" name="parameters">

</wsdl:part></wsdl:message><wsdl:portType name="TestWebService"><wsdl:operation name="getName"><wsdl:input message="impl:getNameRequest" name="getNameRequest">

</wsdl:input><wsdl:output message="impl:getNameResponse" name="getNameResponse">

</wsdl:output></wsdl:operation></wsdl:portType><wsdl:binding name="TestWebServiceSoapBinding" type="impl:TestWebService"><wsdlsoap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/><wsdl:operation name="getName"><wsdlsoap:operation soapAction=""/><wsdl:input name="getNameRequest"><wsdlsoap:body use="literal"/></wsdl:input><wsdl:output name="getNameResponse"><wsdlsoap:body use="literal"/></wsdl:output></wsdl:operation></wsdl:binding><wsdl:service name="TestWebServiceService"><wsdl:port binding="impl:TestWebServiceSoapBinding" name="TestWebService"><wsdlsoap:address location="http://localhost:8080/WebServiceTest/services/TestWebService"/></wsdl:port></wsdl:service></wsdl:definitions>

B)     Creating the WebService Client

  1. Right click and select New-> WebService->WebServiceClientpage5
    2. Paste the WSDL path in server definition and change the client project to WebServiceTestClient( you can give anything as a name)
    3. Click Next and Finish
    4. It will create a new java dynamic project with named as WebServiceTestClient and some java files

page6

5. Open TestWebServiceProxy.java and write a main() method in that

TestWebServiceProxy.java

public static void main(String... args){
  try{
    TestWebServiceProxy proxy = new TestWebServiceProxy();
    String name = proxy.getName("webservice");
    System.out.println("name -->"+name);
   }catch(RemoteException re){
     re.printStackTrace();
  }
}

C)     Running the client

Right click on TestWebServiceProxy.java and run as java application, it will print the result in Uppercase.

Categories: Java, WebService

How MVC belongs to only Presentation Layer?

September 16, 2012 4 comments

Spring MVC in simple terms:

It is a presentation framework, you may have doubt “How MVC belongs to only presentation layer”.

MVC Framework:

View and Controller belongs to Presentation Layer as Controller takes the URL and directs to appropriate View based on the given URL.

 MVC Flow:

  1. Request comes to the controller, controller decides is there any business logic to be implemented for this request or not.
  2.  If no business logic required it will redirect to the appropriate View. Ex: if we are requesting a login form no business logic required here so controller directly redirect login.jsp.
  3. If business logic required to the particular request it will call the appropriate Service class to process the request. Based on the service object response, controller redirects to the appropriate view.
  4. In the view if there is any data is to be shown, then the data will be taken from appropriate model.

With the above diagram View and Controller directly interacting with Presentation Layer.

And model is used by View to show the data.

So MVC belongs to Presentation Layer

MVC in Three tier architecture:

In three tier architecture we have Presentation Tier, Middle Tier, Data Access Tier, simply we can call Presentation layer, Service layer  and DAO Layer.

Presentation layer interacts with the Service layer and Service layer interacts with DAO layer.

The Flow will be like this:

  1. Request  comes to controller and controller decides whether this request needs any business logic to be implemented or not
  2. If no it simply returns a view.
  3. If yes it interacts with Service Layer and Service Layer interacts with DAO Layer
  4. Later the based on the response from Service Layer appropriate View will be shown by the Controller.

Spring recommends the same model can be used for presentation layer, In Struts we have form beans as presentation layer model. But in Spring we can use the same model across all the Three Layers.

Categories: Java, Spring

Inversion of Control – Dependency Injection explained in simple terms

September 15, 2012 3 comments

Inversion of Control – Dependency Injection:

Instead of Object creating its dependencies, let container create and inject into Object. Control is being inverted from Object to Container.

Encapsulation says “The Caller should know its dependencies”

IOC  says “The Caller should know its dependency interfaces”

If the caller doesn’t know its dependencies and knows only interfaces, we can give any of the class to the Object.  Will explain with an example

Let’s Say we have a

package com.java2practice;
public class UsersListFromDB{
     public void printUsers(){
System.out.println(“printing users from database”);
     }
}

 

And UsersView to use the UsersListFromDB,

package com.java2practice;
public class UsersView{
 private UsersListFromDB userListFromDB = new UsersListFromDB();
 public void printUsers(){
      userListFromDB.printUsers();
 }
}

Now create a client program to access the UsersView.java

package com.java2practice;
public class UsersViewTest{
 public static void main(String[] args){
      UsersView usersView = new UsersView();
      usersView.printUsers();
 }
}

If we use like this, the object  UsersListFromDB is tightly coupled with UsersView. If we want to show UsersListFromExcel it won’t be possible.

For this we need to create an interface called

public interface UsersList{
       public void printUsers();
}

And make the UsersListFromDB, UsersListFromExcel implement the UsersList like below

public class UsersListFromDB implements UsersList{
       public void printUsers(){
System.out.println(“users list printing from database”);
       }
}

public class UsersListFromExcel implements UsersList{
       public void printUsers(){
System.out.println(“users list printing from excel”);
       }
}

Now we can change our UsersView class to

public class UsersView{
       private UsersList userList = new UsersListFromDB();
       public void printUsers(){
userList.printUsers();
       }
}

This concept is called interaface referencing. One of the object oriented principle Program to interface not program to class”

But still our problem is not solved, with out changing the UsersView we can not add UsersListFromExcel

Now We will try with Factory Design pattern

public class UsersFactory{
       public UsersList getUsersList(){
                 return new UsersListFromDB();
       }
}

In the UsersView.java we need to call this UsersFactory to get the appropriate object.

public UsersView{
       UsersList usersList = new UsersFactory().getUsersList();
       public void printUsers(){
usersList.printUsers();
       }
}

Now the client program will look like this


public class UsersViewTest{
       public static void main(String[] args){
              UsersView usersView = new UsersView();
              usersView.printUsers();
       }
}

This is more elegant and with out touching UsersView.java file we can switch to UsersListFromExcel  or UsersListFromDB by changing UsersFactory.

But still we need to change the UsersFactory.

With spring IOC our UsersView.java will look like this

public class UsersView{
       private UsersList usersList;
       public void setUsersList(UsersList usersList){
              this.usersList = usersList;
       }
       public void printUsers(){
             usersList.printUsers();
       }
}

That’s it, we don’t need to bother about instantiating the UsersList interface with its implemented classes.

To tell the container about our Java classes we need to write configuration file.

Bean-config.xml


<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

      <bean id="usersListFromDB" class="com.java2practice.UsersListFromDB"/>
      <bean id="usersListFromExcel" class="com.java2practice.UsersListFromExcel/">
      <bean id="userView">
<property ref=” usersListFromDB” />
      </bean>
</beans>

We have to write our client program to use all these:

public class UesrsViewTest{
       public static void main(String[] args){
              ApplicationContext context = new ClassPathXmlApplicationContext("bean-config.xml");
              UsersView usersView = (UsersView)context.getBean(“userView”);
              usersView.printUsers();
       }
}

Here ApplicationContext will read the bean configuration file and accordingly it will inject the dependencies into the UsersView.java

When we are calling context.getBean(“userView”) it will return UsersView with dependencies injected into it.

If we want to use UsersListFromExcel, just we need to change in configuration file

Then the out put will be “printing users from excel file”

Categories: Spring

Creating a HBase table through Java program

September 11, 2012 2 comments

To create a HBase table through Java program. We need to use HBaseConfiguration class

this is the main class which holds the configuration details about HBase.

then we have to add our hbase-site.xml to the HBaseConfiguration.
After preparing the configuration correctly pass this to HBaseAdmin. To specify the HBase table name HTableDescriptor will be used and

HColumnDescriptor is used for Column names.

After all set up is done call the createTable method of HBaseAdmin


import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.client.HBaseAdmin;

public class HbaseTableCreator {

  public static void main(String[] args) throws Exception {

   HBaseConfiguration conf = new HBaseConfiguration();
   conf.addResource("conf/hbase-site.xml");
   conf.set("hbase.master","localhost:60000");

   HBaseAdmin hbase = new HBaseAdmin(conf);
   HTableDescriptor desc = new HTableDescriptor("sample");
   HColumnDescriptor meta = new HColumnDescriptor("samplecolumn1".getBytes());
   HColumnDescriptor prefix = new HColumnDescriptor("samplecolumn2".getBytes());
   desc.addFamily(meta);
   desc.addFamily(prefix);
   hbase.createTable(desc);

 }

}

After successful running of the above program, check with hbase shell whether the table is created or not.

Categories: HBase, Java

HBase installation on Ubuntu

September 11, 2012 Leave a comment

Steps to install HBase on Ubuntu Machine:

  1. Download latest Hbase  from http://hbase.apache.org/
  2. extract it to hbase
  3. Set JAVA_HOME variable in conf/hbase-env.sh
  4. Add hbase/bin to PATH variable
  5. go to hbase folder
  6. $bin/hbase  if it is giving some thing means hbase installed correctly

Start and Stop the HBase:

  1. Start the hbase : $bin/hbase start-hbase.sh
  2. Stop the hbase : $bin/hbase stop-hbase.sh // this will take time and remember stop the hadoop first and then stop the hbase.

HBase Shell Commands:

  1. $bin/hbase shell run this command to enter into hbase shell
  2. To see list of tables created in hbase $bin/hbase list
  3. To create a table in hbase  $create ‘test’,’cf’
  4. Insert some values into the above created test $put ‘test’,’row1’,’cf:a’,’value1’
  5. To see the data $ scan ‘test’
  6. To get one row from the hbase table $ get ‘test’,’row1’.

To Delete Hbase table:

  1. after disabling we can able to drop it $disable ‘test’ and then $drop ‘test’

Hope it helps.

Thanks.

Categories: HBase

Why Integer Object will behave like this?


Integer i1 = 127;

Integer i2 = 127;

System.out.println(i1==i2);

System.out.println(i1.equals(i2));

Integer i1 = 128;

Integer i2 = 128;

System.out.println(i1==i2);

System.out.println(i1.equals(i2));

O/P

true , true,  false ,true

Have you wondered by seeing the output, it should be false, true, false, true right?

But if you run the code it gives the out put as true, true, false, true.

why because Integer object have cache values between -128 to 127.

So first it will be true in the case of 127 as it is in the range of cached values.

But latter case if false as 128 wont fall under the cached values.

http://docs.oracle.com/javase/6/docs/api/java/lang/Integer.html#valueOf%28int%29

Categories: Java