Printing thread id in log file using log4j

Question

I am trying to print the id of the thread for which the logging is being done in my logfile. I did it at code level by log.info(Thread.currentThread().getId()) where "log" is Logger class object but this is not what i exactly want. Actually my application is a large distributed application and it is not possible to add Thread.currentThread().getId() with every log.info("something") in the code. Is there anyway by which i can just make any change in my log4j.xml file and print threads id for every log.info in my code. This is my log4j.xml

<log4j:configuration debug="true">
<!-- File Appenders -->

<appender name="EventsAndErrorsFileAppender" class="org.apache.log4j.RollingFileAppender">
    <param name="File" value="EventsAndErrors.xml" />
    <param name="Datepattern" value="'.'yyyy-MM-dd-HH" />
    <param name="MaxFileSize" value="1000KB" />
    <param name="MaxBackupIndex" value="140" />
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%d{ISO8601} %-5p [%C] %m%n" />
    </layout>
    <filter class="org.apache.log4j.varia.LevelRangeFilter">
        <param name="LevelMin" value="INFO" />
        <param name="LevelMax" value="ERROR" />
    </filter>
</appender>

<root>
    <priority value="debug" />
    <appender-ref ref="EventsAndErrorsFileAppender" />
    <appender-ref ref="ExceptionFileAppender" />
</root>

Now i am assuming that I can add something in my Layout in xml to print the thread. I am also attaching the sample code in which i am trying this just for reference

import org.apache.log4j.Logger;

class MyThread extends Thread implements MyInterface
  {
   public void run()
    {
    int i = 0;
    while(i < 10)
    {
        System.out.println(Thread.currentThread().getId()+"In first        thread");
        log.info(Thread.currentThread().getId());
        log.error(Thread.currentThread().getId());
        System.out.println();
        i++;
    }   

  }
}
class MyThread1 extends Thread implements MyInterface
{

public void run()
{
    int i = 0;
    while(i < 10)
    {
        System.out.println(Thread.currentThread().getId()+"In secound thread");
        log.info(Thread.currentThread().getId());
        log.debug("debug");
        System.out.println();
        i++;
    }
}
}

public class MyClass implements MyInterface
{
 public static void main(String[] args) {
    // TODO Auto-generated method stub


    MyThread thread1 = new MyThread();
    MyThread1 thread2 = new MyThread1();


    log.info("logging stareted");
    thread1.start();
    thread2.start();
 } 
}

Any guidance would be aprreciated. Thanks

Answer 1

%t in the ConversionPattern gives you the thread's name.

Not the same as Thread ID but better than nothing and works without touching the code.

Update: As yuugen's answer points out: in log4j 2.x there is %tid for thread id. (+1 for his answer from me, adding it here for completeness. If this helps you please upvote his answer!)

Answer 2

In log4j 2 https://logging.apache.org/log4j/2.x/manual/layouts.html#PatternLayout

%tid prints the thread ID