Merge remote-tracking branch 'refs/remotes/eugenp/master'

apache-commons-math/pom.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>apache-commons-math</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>3.6.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    
+</project>

apache-commons-math/src/test/java/com/baeldung/commons/math/ComplexTests.java

@@ -0,0 +1,20 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.complex.Complex;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ComplexTests {
+
+    @Test
+    public void whenComplexPow_thenCorrect() {
+        Complex first  = new Complex(1.0, 3.0);
+        Complex second = new Complex(2.0, 5.0);
+
+        Complex power = first.pow(second);
+
+        Assert.assertEquals(-0.007563724861696302, power.getReal(), 1e-7);
+        Assert.assertEquals(0.01786136835085382, power.getImaginary(), 1e-7);
+    }
+
+}

apache-commons-math/src/test/java/com/baeldung/commons/math/FractionTests.java

@@ -0,0 +1,20 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.fraction.Fraction;
+import org.apache.commons.math3.fraction.FractionFormat;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class FractionTests {
+
+    @Test
+    public void whenFractionAdd_thenCorrect() {
+        Fraction lhs = new Fraction(1, 3);
+        Fraction rhs = new Fraction(2, 5);
+        Fraction sum = lhs.add(rhs);
+
+        Assert.assertEquals(11, sum.getNumerator());
+        Assert.assertEquals(15, sum.getDenominator());
+    }
+
+}

apache-commons-math/src/test/java/com/baeldung/commons/math/GeometryTests.java

@@ -0,0 +1,21 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.geometry.euclidean.twod.Line;
+import org.apache.commons.math3.geometry.euclidean.twod.Vector2D;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class GeometryTests {
+
+    @Test
+    public void whenLineIntersection_thenCorrect() {
+        Line l1 = new Line(new Vector2D(0, 0), new Vector2D(1, 1), 0);
+        Line l2 = new Line(new Vector2D(0, 1), new Vector2D(1, 1.5), 0);
+
+        Vector2D intersection = l1.intersection(l2);
+
+        Assert.assertEquals(2, intersection.getX(), 1e-7);
+        Assert.assertEquals(2, intersection.getY(), 1e-7);
+    }
+
+}

apache-commons-math/src/test/java/com/baeldung/commons/math/IntegrationTests.java

@@ -0,0 +1,21 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.analysis.UnivariateFunction;
+import org.apache.commons.math3.analysis.integration.SimpsonIntegrator;
+import org.apache.commons.math3.analysis.integration.UnivariateIntegrator;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class IntegrationTests {
+
+    @Test
+    public void whenUnivariateIntegratorIntegrate_thenCorrect() {
+        final UnivariateFunction function = v -> v;
+        final UnivariateIntegrator integrator = new SimpsonIntegrator(1.0e-12, 1.0e-8, 1, 32);
+
+        final double i = integrator.integrate(100, function, 0, 10);
+
+        Assert.assertEquals(16 + 2d/3d, i, 1e-7);
+    }
+
+}

apache-commons-math/src/test/java/com/baeldung/commons/math/LinearAlgebraTests.java

@@ -0,0 +1,25 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.linear.*;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class LinearAlgebraTests {
+
+    @Test
+    public void whenDecompositionSolverSolve_thenCorrect() {
+        RealMatrix a =
+                new Array2DRowRealMatrix(new double[][] { { 2, 3, -2 }, { -1, 7, 6 }, { 4, -3, -5 } },
+                        false);
+        RealVector b = new ArrayRealVector(new double[] { 1, -2, 1 }, false);
+
+        DecompositionSolver solver = new LUDecomposition(a).getSolver();
+
+        RealVector solution = solver.solve(b);
+
+        Assert.assertEquals(-0.3698630137, solution.getEntry(0), 1e-7);
+        Assert.assertEquals(0.1780821918, solution.getEntry(1), 1e-7);
+        Assert.assertEquals(-0.602739726, solution.getEntry(2), 1e-7);
+    }
+
+}

apache-commons-math/src/test/java/com/baeldung/commons/math/ProbabilitiesTests.java

@@ -0,0 +1,15 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.distribution.NormalDistribution;
+import org.junit.Test;
+
+public class ProbabilitiesTests {
+
+    @Test
+    public void whenNormalDistributionSample_thenSuccess() {
+        final NormalDistribution normalDistribution = new NormalDistribution(10, 3);
+
+        System.out.println(normalDistribution.sample());
+    }
+
+}

apache-commons-math/src/test/java/com/baeldung/commons/math/RootFindingTests.java

@@ -0,0 +1,20 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.analysis.UnivariateFunction;
+import org.apache.commons.math3.analysis.solvers.BracketingNthOrderBrentSolver;
+import org.apache.commons.math3.analysis.solvers.UnivariateSolver;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class RootFindingTests {
+
+    @Test
+    public void whenUnivariateSolverSolver_thenCorrect() {
+        final UnivariateFunction function = v -> Math.pow(v, 2) - 2;
+        UnivariateSolver solver = new BracketingNthOrderBrentSolver(1.0e-12, 1.0e-8, 5);
+        double c = solver.solve(100, function, -10.0, 10.0, 0);
+
+        Assert.assertEquals(-Math.sqrt(2), c, 1e-7);
+    }
+
+}

apache-commons-math/src/test/java/com/baeldung/commons/math/StatisticsTests.java

@@ -0,0 +1,38 @@
+package com.baeldung.commons.math;
+
+import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class StatisticsTests {
+
+    private double[] values;
+    private DescriptiveStatistics descriptiveStatistics;
+
+    @Before
+    public void setUp() {
+        values = new double[] {65, 51 , 16, 11 , 6519, 191 ,0 , 98, 19854, 1, 32};
+
+        descriptiveStatistics = new DescriptiveStatistics();
+        for(double v : values) {
+            descriptiveStatistics.addValue(v);
+        }
+    }
+
+    @Test
+    public void whenDescriptiveStatisticsGetMean_thenCorrect() {
+        Assert.assertEquals(2439.8181818181815, descriptiveStatistics.getMean(), 1e-7);
+    }
+
+    @Test
+    public void whenDescriptiveStatisticsGetMedian_thenCorrect() {
+        Assert.assertEquals(51, descriptiveStatistics.getPercentile(50), 1e-7);
+    }
+
+    @Test
+    public void whenDescriptiveStatisticsGetStandardDeviation_thenCorrect() {
+        Assert.assertEquals(6093.054649651221, descriptiveStatistics.getStandardDeviation(), 1e-7);
+    }
+
+}

apache-fop/src/main/resources/logback.xml

@@ -1,5 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-
     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
@@ -7,10 +7,13 @@
         </encoder>
     </appender>
 
-    <!-- <logger name="org.springframework" level="WARN" /> -->
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>
-
 </configuration>

apache-velocity/src/main/resources/logback.xml

@@ -1,23 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-    
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<layout class="ch.qos.logback.classic.PatternLayout">
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-			<Pattern>
-				%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n
-			</Pattern>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-		</layout>
-	</appender>
-
-	<logger name="com.baeldung.apache.velocity.service" level="debug"
-		additivity="false">
-		<appender-ref ref="STDOUT" />
-	</logger>
-
-	<root level="error">
-		<appender-ref ref="STDOUT" />
-	</root>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

aspectj/pom.xml

@@ -70,11 +70,6 @@
             <artifactId>spring-aop</artifactId>
             <version>4.3.4.RELEASE</version>
         </dependency>
-        <dependency>
-            <groupId>log4j</groupId>
-            <artifactId>log4j</artifactId>
-            <version>1.2.17</version>
-        </dependency>
     </dependencies>
 
     <build>

aspectj/src/main/resources/log4j.properties

@@ -1,10 +0,0 @@
-log4j.rootLogger=TRACE, stdout
-
-# Redirect log messages to console
-log4j.appender.stdout=org.apache.log4j.ConsoleAppender
-log4j.appender.stdout.Target=System.out
-log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
-log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
-
-log4j.logger.org.springframework.aop.interceptor.PerformanceMonitorInterceptor=TRACE, stdout
-log4j.logger.com.baeldung.performancemonitor.MyPerformanceMonitorInterceptor=INFO, stdout

aspectj/src/main/resources/logback.xml

@@ -1,18 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<layout class="ch.qos.logback.classic.PatternLayout">
-		      <pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg %n</pattern>
-	    </layout>
-	</appender>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-	<logger name="com.baeldung.hazelcast" level="INFO" additivity="false">
-		<appender-ref ref="STDOUT" />
-  	</logger>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
-	<root level="DEBUG">          
-		<appender-ref ref="STDOUT" />
-	</root>  
-  
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

core-java-9/src/main/resources/logback.xml

@@ -1,5 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-
     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
@@ -7,10 +7,13 @@
         </encoder>
     </appender>
 
-    <!-- <logger name="org.springframework" level="WARN" /> -->
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
     <root level="INFO">
-        <appender-ref ref="STDOUT"/>
+        <appender-ref ref="STDOUT" />
     </root>
-
 </configuration>

core-java/README.md

@@ -91,4 +91,4 @@
 - [Avoiding ConcurrentModificationException when iterating and removing](http://www.baeldung.com/avoiding-concurrentmodificationexception-when-iterating-and-removing)
 - [Removing all nulls from a List in Java](http://www.baeldung.com/java-remove-nulls-from-list)
 - [Removing all duplicates from a List in Java](http://www.baeldung.com/java-remove-duplicates-from-list)
-
+- [An Introduction to ThreadLocal in Java](http://www.baeldung.com/java-threadlocal)

core-java/src/main/java/com/baeldung/logforging/LogForgingDemo.java

@@ -14,9 +14,9 @@ public class LogForgingDemo {
 
 	public static void main(String[] args) {
 		LogForgingDemo demo = new LogForgingDemo();
-		demo.addLog(String.valueOf(300));
-		demo.addLog(String.valueOf(300 + "\n\nweb - 2017-04-12 17:47:08,957 [main] INFO Amount reversed successfully"));
-		demo.addLog(String.valueOf(encode(300 + "\n\nweb - 2017-04-12 17:47:08,957 [main] INFO Amount reversed successfully")));
+		demo.addLog("300");
+		demo.addLog("300 \n\nweb - 2017-04-12 17:47:08,957 [main] INFO Amount reversed successfully");
+		demo.addLog(encode("300 \n\nweb - 2017-04-12 17:47:08,957 [main] INFO Amount reversed successfully"));
 	}
 
 	public static String encode(String message) {

core-java/src/main/resources/logback.xml

@@ -1,5 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-
     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
@@ -7,10 +7,13 @@
         </encoder>
     </appender>
 
-    <!-- <logger name="org.springframework" level="WARN" /> -->
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>
-
 </configuration>

couchbase-sdk/src/main/resources/logback.xml

@@ -1,5 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-
     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
@@ -8,10 +8,12 @@
     </appender>
 
     <logger name="org.springframework" level="WARN" />
-    <logger name="com.baeldung" level="DEBUG" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>
-
 </configuration>

couchbase-sdk/src/test/resources/logback.xml

@@ -1,5 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-
     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
@@ -8,10 +8,12 @@
     </appender>
 
     <logger name="org.springframework" level="WARN" />
-    <logger name="com.baeldung" level="DEBUG" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>
-
 </configuration>

gson/src/main/resources/logback.xml

@@ -1,20 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<encoder>
-			<pattern>web - %date [%thread] %-5level %logger{36} - %message%n
-			</pattern>
-		</encoder>
-	</appender>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-	<logger name="org.springframework" level="WARN" />
-	<logger name="org.springframework.transaction" level="WARN" />
-
-	<!-- in order to debug some marshalling issues, this needs to be TRACE -->
-	<logger name="org.springframework.web.servlet.mvc" level="WARN" />
-
-	<root level="INFO">
-		<appender-ref ref="STDOUT" />
-	</root>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

guava/src/main/resources/logback.xml

@@ -1,20 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<encoder>
-			<pattern>web - %date [%thread] %-5level %logger{36} - %message%n
-			</pattern>
-		</encoder>
-	</appender>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-	<logger name="org.springframework" level="WARN" />
-	<logger name="org.springframework.transaction" level="WARN" />
-
-	<!-- in order to debug some marshalling issues, this needs to be TRACE -->
-	<logger name="org.springframework.web.servlet.mvc" level="WARN" />
-
-	<root level="INFO">
-		<appender-ref ref="STDOUT" />
-	</root>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

handling-spring-static-resources/src/main/resources/logback.xml

@@ -1,20 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<encoder>
-			<pattern>web - %date [%thread] %-5level %logger{36} - %message%n
-			</pattern>
-		</encoder>
-	</appender>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-	<logger name="org.springframework" level="WARN" />
-	<logger name="org.springframework.transaction" level="WARN" />
-
-	<!-- in order to debug some marshalling issues, this needs to be TRACE -->
-	<logger name="org.springframework.web.servlet.mvc" level="WARN" />
-
-	<root level="INFO">
-		<appender-ref ref="STDOUT" />
-	</root>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

hazelcast/src/main/resources/logback.xml

@@ -1,18 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<layout class="ch.qos.logback.classic.PatternLayout">
-		      <pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg %n</pattern>
-	    </layout>
-	</appender>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-	<logger name="com.baeldung.hazelcast" level="INFO" additivity="false">
-		<appender-ref ref="STDOUT" />
-  	</logger>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
-	<root level="DEBUG">          
-		<appender-ref ref="STDOUT" />
-	</root>  
-  
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

httpclient/src/main/resources/logback.xml

@@ -1,5 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-
     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
@@ -7,11 +7,13 @@
         </encoder>
     </appender>
 
-    <logger name="org.apache.http" level="DEBUG" />
-    <logger name="org.apache.http.wire" level="INFO" />
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>
-
 </configuration>

jackson/src/main/resources/logback.xml

@@ -1,20 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<encoder>
-			<pattern>web - %date [%thread] %-5level %logger{36} - %message%n
-			</pattern>
-		</encoder>
-	</appender>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-	<logger name="org.springframework" level="WARN" />
-	<logger name="org.springframework.transaction" level="WARN" />
-
-	<!-- in order to debug some marshalling issues, this needs to be TRACE -->
-	<logger name="org.springframework.web.servlet.mvc" level="WARN" />
-
-	<root level="INFO">
-		<appender-ref ref="STDOUT" />
-	</root>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

jaxb/src/main/resources/logback.xml

@@ -1,18 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
+            </pattern>
+        </encoder>
+    </appender>
 
-	<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-		<layout class="ch.qos.logback.classic.PatternLayout">
-		      <pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg %n</pattern>
-	    </layout>
-	</appender>
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
 
-	<logger name="com.baeldung.hazelcast" level="INFO" additivity="false">
-		<appender-ref ref="STDOUT" />
-  	</logger>
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
 
-	<root level="DEBUG">          
-		<appender-ref ref="STDOUT" />
-	</root>  
-  
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
 </configuration>

jsf/src/main/resources/logback.xml

@@ -1,5 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-
     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>web - %date [%thread] %-5level %logger{36} - %message%n
@@ -7,8 +7,13 @@
         </encoder>
     </appender>
 
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+
     <root level="INFO">
         <appender-ref ref="STDOUT" />
     </root>
-
 </configuration>

kotlin/src/test/kotlin/com/baeldung/kotlin/GenericsTest.kt

@@ -0,0 +1,143 @@
+package com.baeldung.kotlin
+
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class GenericsTest {
+
+    @Test
+    fun givenParametrizeClass_whenInitializeItWithSpecificType_thenShouldBeParameterized() {
+        //given
+        val parameterizedClass = ParameterizedClass<String>("string-value")
+
+        //when
+        val res = parameterizedClass.getValue()
+
+        //then
+        assertTrue(res is String)
+    }
+
+    @Test
+    fun givenParametrizeClass_whenInitializeIt_thenShouldBeParameterizedByInferredType() {
+        //given
+        val parameterizedClass = ParameterizedClass("string-value")
+
+        //when
+        val res = parameterizedClass.getValue()
+
+        //then
+        assertTrue(res is String)
+    }
+
+    @Test
+    fun givenParameterizedProducerByOutKeyword_whenGetValue_thenCanAssignItToSuperType() {
+        //given
+        val parameterizedProducer = ParameterizedProducer("string")
+
+        //when
+        val ref: ParameterizedProducer<Any> = parameterizedProducer
+
+        //then
+        assertTrue(ref is ParameterizedProducer<Any>)
+    }
+
+    @Test
+    fun givenParameterizedConsumerByInKeyword_whenGetValue_thenCanAssignItToSubType() {
+        //given
+        val parameterizedConsumer = ParameterizedConsumer<Number>()
+
+        //when
+        val ref: ParameterizedConsumer<Double> = parameterizedConsumer
+
+        //then
+        assertTrue(ref is ParameterizedConsumer<Double>)
+    }
+
+    @Test
+    fun givenTypeProjections_whenOperateOnTwoList_thenCanAcceptListOfSubtypes() {
+        //given
+        val ints: Array<Int> = arrayOf(1, 2, 3)
+        val any: Array<Any?> = arrayOfNulls(3)
+
+        //when
+        copy(ints, any)
+
+        //then
+        assertEquals(any[0], 1)
+        assertEquals(any[1], 2)
+        assertEquals(any[2], 3)
+
+    }
+
+    fun copy(from: Array<out Any>, to: Array<Any?>) {
+        assert(from.size == to.size)
+        for (i in from.indices)
+            to[i] = from[i]
+    }
+
+    @Test
+    fun givenTypeProjection_whenHaveArrayOfIn_thenShouldAddElementsOfSubtypesToIt() {
+        //given
+        val objects: Array<Any?> = arrayOfNulls(1)
+
+        //when
+        fill(objects, 1)
+
+        //then
+        assertEquals(objects[0], 1)
+    }
+
+    fun fill(dest: Array<in Int>, value: Int) {
+        dest[0] = value
+    }
+
+    @Test
+    fun givenStartProjection_whenPassAnyType_thenCompile() {
+        //given
+        val array = arrayOf(1,2,3)
+
+        //then
+        printArray(array)
+
+    }
+
+    fun printArray(array: Array<*>) {
+        array.forEach { println(it) }
+    }
+
+    @Test
+    fun givenFunctionWithDefinedGenericConstraints_whenCallWithProperType_thenCompile(){
+        //given
+        val listOfInts = listOf(5,2,3,4,1)
+
+        //when
+        val sorted = sort(listOfInts)
+
+        //then
+        assertEquals(sorted, listOf(1,2,3,4,5))
+    }
+
+    fun <T: Comparable<T>> sort(list: List<T>): List<T>{
+        return list.sorted()
+    }
+
+    class ParameterizedClass<A>(private val value: A) {
+
+        fun getValue(): A {
+            return value
+        }
+    }
+
+    class ParameterizedProducer<out T>(private val value: T) {
+        fun get(): T {
+            return value
+        }
+    }
+
+    class ParameterizedConsumer<in T> {
+        fun toString(value: T): String {
+            return value.toString()
+        }
+    }
+}

libraries/README.md

@@ -5,7 +5,8 @@
 - [String Processing with Apache Commons Lang 3](http://www.baeldung.com/string-processing-commons-lang)
 - [Introduction to Javatuples](http://www.baeldung.com/java-tuples)
 - [Introduction to Javassist](http://www.baeldung.com/javassist)
-- [Embedded Jetty Server in Java](http://www.baeldung.com/jetty-embedded) 
+- [Embedded Jetty Server in Java](http://www.baeldung.com/jetty-embedded)
+- [Introduction to Apache Flink with Java](http://www.baeldung.com/apache-flink)
 
 
 The libraries module contains examples related to small libraries that are relatively easy to use and does not require any separate module of its own.