Examples done.

log-mdc-ndc/pom.xml

@@ -7,27 +7,17 @@
 	<name>logmdcndc</name>
 	<description>tutorial on logging with MDC and NDC</description>
 	
-    <parent>
-        <groupId>org.springframework.boot</groupId>
-        <artifactId>spring-boot-starter-parent</artifactId>
-        <version>1.4.1.RELEASE</version>
-    </parent>
-
 	<dependencies>
 	
 	    <dependency>
-            <groupId>org.springframework.boot</groupId>
+	        <groupId>org.springframework</groupId>
-            <artifactId>spring-boot-starter-web</artifactId>
+	        <artifactId>spring-context</artifactId>
+	        <version>4.3.3.RELEASE</version>
 	    </dependency>
 	    <dependency>
-            <groupId>org.springframework.boot</groupId>
+	        <groupId>org.springframework</groupId>
-            <artifactId>spring-boot-starter-test</artifactId>
+	        <artifactId>spring-webmvc</artifactId>
-            <scope>test</scope>
+	        <version>4.3.3.RELEASE</version>
-        </dependency>
-        <dependency>
-            <groupId>com.jayway.jsonpath</groupId>
-            <artifactId>json-path</artifactId>
-            <scope>test</scope>
 	    </dependency>	    
 	
 		<!--log4j dependencies -->

log-mdc-ndc/src/main/java/com/baeldung/mdc/BusinessService.java

@@ -2,6 +2,8 @@ package com.baeldung.mdc;
 
 public interface BusinessService {
 
-	boolean transfer(Long amount);
+	/** Sample service transferring a given amount of money. 
+	 * @return {@code true} when the transfer complete successfully, {@code false} otherwise. */
+	boolean transfer(long amount);
 
 }

log-mdc-ndc/src/main/java/com/baeldung/mdc/DefaultBusinessService.java

@@ -1,15 +1,19 @@
 package com.baeldung.mdc;
 
+/**
+ * A fake {@link BusinessService} simulating an actual one.
+ */
 public class DefaultBusinessService implements BusinessService {
 
-	@Override
+	public boolean transfer(long amount) {
-	public boolean transfer(Long amount) {
 		try {
-			Thread.sleep((long) (Math.random()*1000));
+			// let's pause randomly to properly simulate an actual system. 
+			Thread.sleep((long) (500 + Math.random()*500));
 		} catch (InterruptedException e) {
-			// should not happen
+			// should never happen
 		}
-		return Math.random() >= 0.5;
+		// let's simulate both failing and successful transfers 
+		return Math.random() >= 0.25;
 	}
 
 }

log-mdc-ndc/src/main/java/com/baeldung/mdc/DelegateBusiness.java

@@ -9,21 +9,20 @@ public abstract class DelegateBusiness {
 		this.delegate = delegate;
 	}
 	
-
 	public DelegateBusiness() {
 		this( new DefaultBusinessService() );
 	}
 
-	public boolean transfer(Long amount) {
+	public boolean transfer(long amount) {
-		preTransfer();
+		preTransfer(amount);
 		boolean outcome = delegate.transfer(amount);
-		postTransfer(outcome);
+		postTransfer(amount, outcome);
 		return outcome;
 	}
 
-	abstract protected void postTransfer(boolean outcome);
+	abstract protected void postTransfer(long amount, boolean outcome);
 
-	abstract protected void preTransfer();
+	abstract protected void preTransfer(long amount);
 	
 	
 	

log-mdc-ndc/src/main/java/com/baeldung/mdc/GenericApp.java

@@ -1,46 +1,25 @@
 package com.baeldung.mdc;
 
-import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
-import org.apache.log4j.MDC;
+import org.apache.log4j.Logger;
 
-import com.baeldung.mdc.log4j.Log4jBusinessService;
+import com.baeldung.mdc.log4j.Log4JRunnable;
 
 public class GenericApp {
+		
 	public static void main(String[] args) {
 		
 		ExecutorService executor = Executors.newFixedThreadPool(3);
 		TransactionFactory transactionFactory = new TransactionFactory();
 		
 		for(int i=0; i<10; i++){
-			
+			final Transaction tx = transactionFactory.newInstance();
-			TransactionContext tx = transactionFactory.buildTransaction();
+			executor.submit(new Log4JRunnable(tx));
-			
-			executor.submit(new Runnable() {
-				@Override
-				public void run() {
-					new DelegateBusiness() {
-						
-						@Override
-						protected void preTransfer() {
-							MDC.put("transaction.id", tx.getTransactionId());
-							MDC.put("transaction.owner", tx.getOwner());
-							MDC.put("transaction.createdAt", tx.getCreatedAt());
 		}
 		
-						@Override
+		executor.shutdown();
-						protected void postTransfer(boolean outcome) {
-							// TODO Auto-generated method stub
-							
-						}
-					}.transfer(
-							tx.getAmount()
-					);
-				}
-			});
-		}
 				
 	}
 }

log-mdc-ndc/src/main/java/com/baeldung/mdc/Transaction.java

@@ -2,18 +2,18 @@ package com.baeldung.mdc;
 
 import java.util.Date;
 
-public class TransactionContext {
+public class Transaction {
 	
 	private String transactionId;
 	private String owner;
 	private Date createdAt;
 	private Long amount;
 	
-	public TransactionContext(String transactionId, String owner) {
+	public Transaction(String transactionId, String owner, long amount) {
 		this.transactionId = transactionId;
 		this.owner = owner;
 		this.createdAt = new Date();
-		this.amount = (long) (Math.random()*100);
+		this.amount = amount;
 	}
 
 	public String getOwner() {

log-mdc-ndc/src/main/java/com/baeldung/mdc/TransactionFactory.java

@@ -1,10 +1,20 @@
 package com.baeldung.mdc;
 
+import static java.lang.Math.floor;
+import static java.lang.Math.random;
+
+import java.util.UUID;
+
 public class TransactionFactory {
 
-	public TransactionContext buildTransaction() {
+	private static final String[] NAMES = {"John", "Susan", "Marc", "Samantha"};
-		TransactionContext ctx = new TransactionContext("" + Math.random(), "owner" + Math.random());
+	
-		return ctx;
+	public Transaction newInstance() {
+		String transactionId = UUID.randomUUID().toString();
+		String owner = NAMES[ (int) floor(random()*NAMES.length) ];
+		long amount = (long) (random()*1500 + 500);
+		Transaction tx = new Transaction(transactionId, owner, amount);
+		return tx;
 	}
 	
 }

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j/Log4JBusinessService.java

@@ -0,0 +1,22 @@
+package com.baeldung.mdc.log4j;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import com.baeldung.mdc.DelegateBusiness;
+
+final class Log4JBusinessService extends DelegateBusiness {
+	
+	private static final Logger logger = LogManager.getLogger();
+
+	@Override
+	protected void preTransfer(long amount) {
+		logger.info("Preparing to transfer {}$.");
+	}
+
+	@Override
+	protected void postTransfer(long amount, boolean outcome) {
+		logger.info("Has transfer of {}$ completed successfully ? {}.");
+	}
+	
+}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j/Log4JRunnable.java

@@ -0,0 +1,25 @@
+package com.baeldung.mdc.log4j;
+
+import org.apache.log4j.MDC;
+
+import com.baeldung.mdc.Transaction;
+
+public class Log4JRunnable implements Runnable {
+	private final Transaction tx;
+
+	public Log4JRunnable(Transaction tx) {
+		this.tx = tx;
+	}
+
+	public void run() {
+
+		MDC.put("transaction.id", tx.getTransactionId());
+		MDC.put("transaction.owner", tx.getOwner());
+		MDC.put("transaction.createdAt", tx.getCreatedAt());
+
+		new Log4JBusinessService().transfer(tx.getAmount());
+
+		MDC.clear();
+
+	}
+}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j/Log4jBusinessService.java

@@ -1,17 +0,0 @@
-package com.baeldung.mdc.log4j;
-
-import org.apache.log4j.Logger;
-
-import com.baeldung.mdc.BusinessService;
-
-public class Log4jBusinessService implements BusinessService {
-	
-	private final static Logger logger = Logger.getLogger(Log4jBusinessService.class);
-	
-	@Override
-	public boolean transfer(Long amount) {
-		logger.info("Executing transaction #" + amount );
-		return false;
-	}
-	
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j/Log4jDemo.java

@@ -1,17 +0,0 @@
-package com.baeldung.mdc.log4j;
-
-public class Log4jDemo {
-	
-	public static void main(String[] args) throws InterruptedException {
-		Log4jExecutor greeter = new Log4jExecutor();
-		Thread thread1 = new Thread(greeter);
-		Thread thread2 = new Thread(greeter);
-		
-		thread1.start();
-		thread2.start();
-		
-		thread1.join();
-		thread2.join();
-	}
-
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j/Log4jExecutor.java

@@ -1,21 +0,0 @@
-package com.baeldung.mdc.log4j;
-
-import org.apache.log4j.MDC;
-
-import com.baeldung.mdc.TransactionContext;
-import com.baeldung.mdc.TransactionFactory;
-
-public class Log4jExecutor implements Runnable {
-	
-	public void run() {
-
-		TransactionContext ctx = new TransactionFactory().buildTransaction();
-
-		MDC.put("transaction.id", ctx.getTransactionId());
-		MDC.put("transaction.owner", ctx.getOwner());
-		MDC.put("transaction.createdAt", ctx.getCreatedAt());
-
-		new Log4jBusinessService().transfer(ctx.getAmount());
-	}
-
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j2/Log4J2BusinessService.java

@@ -0,0 +1,21 @@
+package com.baeldung.mdc.log4j2;
+
+import org.apache.log4j.Logger;
+
+import com.baeldung.mdc.DelegateBusiness;
+
+final class Log4J2BusinessService extends DelegateBusiness {
+	
+	private Logger logger = Logger.getLogger(Log4J2BusinessService.class);
+
+	@Override
+	protected void preTransfer(long amount) {
+		logger .info("Preparing to transfer " + amount + "$.");
+	}
+
+	@Override
+	protected void postTransfer(long amount, boolean outcome) {
+		logger.info("Has transfer of " + amount + "$ completed successfully ? " + outcome + ".");
+	}
+	
+}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j2/Log4J2Runnable.java

@@ -0,0 +1,25 @@
+package com.baeldung.mdc.log4j2;
+
+import org.apache.logging.log4j.ThreadContext;
+
+import com.baeldung.mdc.Transaction;
+
+final class Log4J2Runnable implements Runnable {
+	private final Transaction tx;
+
+	Log4J2Runnable(Transaction tx) {
+		this.tx = tx;
+	}
+
+	public void run() {
+							
+		ThreadContext.put("transaction.id", tx.getTransactionId());
+		ThreadContext.put("transaction.owner", tx.getOwner());
+		ThreadContext.put("transaction.createdAt", tx.getCreatedAt().toString());		
+		
+		new Log4J2BusinessService().transfer(tx.getAmount());
+		
+		ThreadContext.clearAll();
+							
+	}
+}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j2/Log4j2BusinessService.java

@@ -1,20 +0,0 @@
-package com.baeldung.mdc.log4j2;
-
-
-
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-
-import com.baeldung.mdc.BusinessService;
-
-public class Log4j2BusinessService implements BusinessService {
-	
-	private static final Logger logger = LogManager.getLogger(); //Log4j2BusinessService.class);
-	
-	@Override
-	public boolean transfer(Long amount) {
-		logger.info("Executing transaction #{}", amount );
-		return false;
-	}
-	
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j2/Log4j2Demo.java

@@ -1,17 +0,0 @@
-package com.baeldung.mdc.log4j2;
-
-public class Log4j2Demo {
-	
-	public static void main(String[] args) throws InterruptedException {
-		Log4j2Executor greeter = new Log4j2Executor();
-		Thread thread1 = new Thread(greeter);
-		Thread thread2 = new Thread(greeter);
-		
-		thread1.start();
-		thread2.start();
-		
-		thread1.join();
-		thread2.join();
-	}
-
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/log4j2/Log4j2Executor.java

@@ -1,21 +0,0 @@
-package com.baeldung.mdc.log4j2;
-
-import org.apache.logging.log4j.ThreadContext;
-
-import com.baeldung.mdc.TransactionContext;
-import com.baeldung.mdc.TransactionFactory;
-
-public class Log4j2Executor implements Runnable {
-	
-	public void run() {
-
-		TransactionContext ctx = new TransactionFactory().buildTransaction();
-		
-		ThreadContext.put("transaction.id", ctx.getTransactionId());
-		ThreadContext.put("transaction.owner", ctx.getOwner());
-		ThreadContext.put("transaction.createdAt", ctx.getCreatedAt().toString());
-
-		new Log4j2BusinessService().transfer(ctx.getAmount());
-	}
-
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/logback/LogbackBusinessService.java

@@ -1,18 +0,0 @@
-package com.baeldung.mdc.logback;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import com.baeldung.mdc.BusinessService;
-
-public class LogbackBusinessService implements BusinessService {
-
-	private static final Logger logger = LoggerFactory.getLogger(LogbackBusinessService.class);
-
-	@Override
-	public boolean transfer(Long amount) {
-		logger.info("Executing transaction #{}", amount);
-		return false;
-	}
-
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/logback/LogbackDemo.java

@@ -1,17 +0,0 @@
-package com.baeldung.mdc.logback;
-
-public class LogbackDemo {
-	
-	public static void main(String[] args) throws InterruptedException {
-		LogbackExecutor greeter = new LogbackExecutor();
-		Thread thread1 = new Thread(greeter);
-		Thread thread2 = new Thread(greeter);
-		
-		thread1.start();
-		thread2.start();
-		
-		thread1.join();
-		thread2.join();
-	}
-
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/logback/LogbackExecutor.java

@@ -1,23 +0,0 @@
-package com.baeldung.mdc.logback;
-
-import org.slf4j.MDC;
-
-import com.baeldung.mdc.TransactionContext;
-import com.baeldung.mdc.TransactionFactory;
-
-public class LogbackExecutor implements Runnable {
-
-	public void run() {
-
-		TransactionContext ctx = new TransactionFactory().buildTransaction();
-
-		MDC.put("transaction.id", ctx.getTransactionId());
-		MDC.put("transaction.owner", ctx.getOwner());
-		MDC.put("transaction.createdAt", ctx.getCreatedAt().toString());
-
-		new LogbackBusinessService().transfer(ctx.getAmount());
-	}
-
-
-
-}

log-mdc-ndc/src/main/java/com/baeldung/mdc/slf4j/Slf4jBusinessService.java

@@ -0,0 +1,22 @@
+package com.baeldung.mdc.slf4j;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.baeldung.mdc.DelegateBusiness;
+
+final class Slf4jBusinessService extends DelegateBusiness {
+	
+	private static final Logger logger = LoggerFactory.getLogger(Slf4jBusinessService.class);
+
+	@Override
+	protected void preTransfer(long amount) {
+		logger.info("Preparing to transfer " + amount + "$.");
+	}
+
+	@Override
+	protected void postTransfer(long amount, boolean outcome) {
+		logger.info("Has transfer of " + amount + "$ completed successfully ? " + outcome + ".");
+	}
+	
+}

log-mdc-ndc/src/main/java/com/baeldung/mdc/slf4j/Slf4jRunnable.java

@@ -0,0 +1,25 @@
+package com.baeldung.mdc.slf4j;
+
+import org.slf4j.MDC;
+
+import com.baeldung.mdc.Transaction;
+
+final class Slf4jRunnable implements Runnable {
+	private final Transaction tx;
+
+	Slf4jRunnable(Transaction tx) {
+		this.tx = tx;
+	}
+
+	public void run() {
+							
+		MDC.put("transaction.id", tx.getTransactionId());
+		MDC.put("transaction.owner", tx.getOwner());
+		MDC.put("transaction.createdAt", tx.getCreatedAt().toString());		
+		
+		new Slf4jBusinessService().transfer(tx.getAmount());
+		
+		MDC.clear();
+							
+	}
+}

log-mdc-ndc/src/main/java/com/baeldung/web/Application.java

@@ -1,12 +0,0 @@
-package com.baeldung.web;
-
-import org.springframework.boot.SpringApplication;
-import org.springframework.boot.autoconfigure.SpringBootApplication;
-
-@SpringBootApplication
-public class Application {
-
-    public static void main(String[] args) {
-        SpringApplication.run(Application.class, args);
-    }
-}

log-mdc-ndc/src/main/java/com/baeldung/web/GreetingController.java

@@ -1,18 +0,0 @@
-package com.baeldung.web;
-
-import java.util.concurrent.atomic.AtomicLong;
-
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.RequestBody;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RequestParam;
-import org.springframework.web.bind.annotation.RestController;
-
-@RestController
-public class GreetingController {
-
-    @GetMapping("/echo")
-    public String echo(@RequestBody String body) {
-        return body;
-    }
-}

log-mdc-ndc/src/main/resources/log4j.properties

@@ -2,11 +2,13 @@ log4j.appender.consoleAppender=org.apache.log4j.ConsoleAppender
 log4j.appender.consoleAppender.layout=org.apache.log4j.PatternLayout
 
 log4j.appender.file=org.apache.log4j.FileAppender
-log4j.appender.file.File=/tmp/$X{transaction.owner}
+log4j.appender.file.File=/tmp/baeldung.log
 log4j.appender.file.layout=org.apache.log4j.PatternLayout
 
 #note the %X{userName} - this is how you fetch data from Mapped Diagnostic Context (MDC)
-log4j.appender.consoleAppender.layout.ConversionPattern=%-4r [%t] %5p %c %x - %m - owner=%X{transaction.owner} creation=%X{transaction.createdAt}%n
+#log4j.appender.consoleAppender.layout.ConversionPattern=%-4r [%t] %5p %c %x - %m - owner=%X{transaction.owner} creation=%X{transaction.createdAt}%n
-log4j.appender.file.layout.ConversionPattern=%-4r [%t] %5p %c %x - %m - owner=%X{transaction.owner} creation=%X{transaction.createdAt}%n
+#log4j.appender.file.layout.ConversionPattern=%-4r [%t] %5p %c %x - %m - owner=%X{transaction.owner} creation=%X{transaction.createdAt}%n
+log4j.appender.consoleAppender.layout.ConversionPattern=%-4r [%t] %5p %c %x - %m%n
+log4j.appender.file.layout.ConversionPattern=%-4r [%t] %5p %c %x - %m%n
 
-log4j.rootLogger = ALL, consoleAppender, file
+log4j.rootLogger = TRACE, consoleAppender, file