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

.gitignore

@@ -1,3 +1,5 @@
+*/bin/*
+
 *.class
 
 # Package Files #

.travis.yml

@@ -1,11 +1,13 @@
 language: java
 
-install: travis_wait 40 mvn -q clean install -Dgib.enabled=true
+install: travis_wait 60 mvn -q test
+
+before_script:
+  - echo "MAVEN_OPTS='-Xmx2048M -Xss128M -XX:MaxPermSize=2048M -XX:+CMSClassUnloadingEnabled -XX:+UseConcMarkSweepGC -XX:+TieredCompilation -XX:TieredStopAtLevel=1 -XX:-UseGCOverheadLimit'" > ~/.mavenrc
 
 jdk:
   - oraclejdk8
 
-sudo: false
 addons:
   apt:
     packages:
@@ -14,4 +16,6 @@ addons:
 cache:
   directories:
   - .autoconf
-  - $HOME/.m2
+  - $HOME/.m2
+  
+

Twitter4J/README.md

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [Introduction to Twitter4J](http://www.baeldung.com/twitter4j)

algorithms/README.md

@@ -3,3 +3,4 @@
 - [Dijkstra Algorithm in Java](http://www.baeldung.com/java-dijkstra)
 - [Introduction to Cobertura](http://www.baeldung.com/cobertura)
 - [Ant Colony Optimization](http://www.baeldung.com/java-ant-colony-optimization)
+- [Validating Input With Finite Automata in Java](http://www.baeldung.com/finite-automata-java)

algorithms/pom.xml

@@ -10,9 +10,15 @@
 		<maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
 		<exec-maven-plugin.version>1.5.0</exec-maven-plugin.version>
 		<lombok.version>1.16.12</lombok.version>
+		<commons-math3.version>3.6.1</commons-math3.version>
 	</properties>
 
 	<dependencies>
+		<dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
 		<dependency>
 			<groupId>junit</groupId>
 			<artifactId>junit</artifactId>

algorithms/src/main/java/com/baeldung/algorithms/ga/dijkstra/Dijkstra.java

@@ -1,57 +1,57 @@
-package com.baeldung.algorithms.ga.dijkstra;
-
-import java.util.HashSet;
-import java.util.LinkedList;
-import java.util.Map.Entry;
-import java.util.Set;
-
-public class Dijkstra {
-
-    public static Graph calculateShortestPathFromSource(Graph graph, Node source) {
-
-        source.setDistance(0);
-
-        Set<Node> settledNodes = new HashSet<>();
-        Set<Node> unsettledNodes = new HashSet<>();
-        unsettledNodes.add(source);
-
-        while (unsettledNodes.size() != 0) {
-            Node currentNode = getLowestDistanceNode(unsettledNodes);
-            unsettledNodes.remove(currentNode);
-            for (Entry<Node, Integer> adjacencyPair : currentNode.getAdjacentNodes().entrySet()) {
-                Node adjacentNode = adjacencyPair.getKey();
-                Integer edgeWeigh = adjacencyPair.getValue();
-
-                if (!settledNodes.contains(adjacentNode)) {
-                    CalculateMinimumDistance(adjacentNode, edgeWeigh, currentNode);
-                    unsettledNodes.add(adjacentNode);
-                }
-            }
-            settledNodes.add(currentNode);
-        }
-        return graph;
-    }
-
-    private static void CalculateMinimumDistance(Node evaluationNode, Integer edgeWeigh, Node sourceNode) {
-        Integer sourceDistance = sourceNode.getDistance();
-        if (sourceDistance + edgeWeigh < evaluationNode.getDistance()) {
-            evaluationNode.setDistance(sourceDistance + edgeWeigh);
-            LinkedList<Node> shortestPath = new LinkedList<>(sourceNode.getShortestPath());
-            shortestPath.add(sourceNode);
-            evaluationNode.setShortestPath(shortestPath);
-        }
-    }
-
-    private static Node getLowestDistanceNode(Set<Node> unsettledNodes) {
-        Node lowestDistanceNode = null;
-        int lowestDistance = Integer.MAX_VALUE;
-        for (Node node : unsettledNodes) {
-            int nodeDistance = node.getDistance();
-            if (nodeDistance < lowestDistance) {
-                lowestDistance = nodeDistance;
-                lowestDistanceNode = node;
-            }
-        }
-        return lowestDistanceNode;
-    }
-}
+package com.baeldung.algorithms.ga.dijkstra;
+
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.Map.Entry;
+import java.util.Set;
+
+public class Dijkstra {
+
+    public static Graph calculateShortestPathFromSource(Graph graph, Node source) {
+
+        source.setDistance(0);
+
+        Set<Node> settledNodes = new HashSet<>();
+        Set<Node> unsettledNodes = new HashSet<>();
+        unsettledNodes.add(source);
+
+        while (unsettledNodes.size() != 0) {
+            Node currentNode = getLowestDistanceNode(unsettledNodes);
+            unsettledNodes.remove(currentNode);
+            for (Entry<Node, Integer> adjacencyPair : currentNode.getAdjacentNodes().entrySet()) {
+                Node adjacentNode = adjacencyPair.getKey();
+                Integer edgeWeigh = adjacencyPair.getValue();
+
+                if (!settledNodes.contains(adjacentNode)) {
+                    CalculateMinimumDistance(adjacentNode, edgeWeigh, currentNode);
+                    unsettledNodes.add(adjacentNode);
+                }
+            }
+            settledNodes.add(currentNode);
+        }
+        return graph;
+    }
+
+    private static void CalculateMinimumDistance(Node evaluationNode, Integer edgeWeigh, Node sourceNode) {
+        Integer sourceDistance = sourceNode.getDistance();
+        if (sourceDistance + edgeWeigh < evaluationNode.getDistance()) {
+            evaluationNode.setDistance(sourceDistance + edgeWeigh);
+            LinkedList<Node> shortestPath = new LinkedList<>(sourceNode.getShortestPath());
+            shortestPath.add(sourceNode);
+            evaluationNode.setShortestPath(shortestPath);
+        }
+    }
+
+    private static Node getLowestDistanceNode(Set<Node> unsettledNodes) {
+        Node lowestDistanceNode = null;
+        int lowestDistance = Integer.MAX_VALUE;
+        for (Node node : unsettledNodes) {
+            int nodeDistance = node.getDistance();
+            if (nodeDistance < lowestDistance) {
+                lowestDistance = nodeDistance;
+                lowestDistanceNode = node;
+            }
+        }
+        return lowestDistanceNode;
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/ga/dijkstra/Graph.java

@@ -1,21 +1,21 @@
-package com.baeldung.algorithms.ga.dijkstra;
-
-import java.util.HashSet;
-import java.util.Set;
-
-public class Graph {
-
-    private Set<Node> nodes = new HashSet<>();
-
-    public void addNode(Node nodeA) {
-        nodes.add(nodeA);
-    }
-
-    public Set<Node> getNodes() {
-        return nodes;
-    }
-
-    public void setNodes(Set<Node> nodes) {
-        this.nodes = nodes;
-    }
-}
+package com.baeldung.algorithms.ga.dijkstra;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class Graph {
+
+    private Set<Node> nodes = new HashSet<>();
+
+    public void addNode(Node nodeA) {
+        nodes.add(nodeA);
+    }
+
+    public Set<Node> getNodes() {
+        return nodes;
+    }
+
+    public void setNodes(Set<Node> nodes) {
+        this.nodes = nodes;
+    }
+}

algorithms/src/main/java/com/baeldung/algorithms/ga/dijkstra/Node.java

@@ -1,58 +1,58 @@
-package com.baeldung.algorithms.ga.dijkstra;
-
-import java.util.HashMap;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-
-public class Node {
-
-    private String name;
-
-    private LinkedList<Node> shortestPath = new LinkedList<>();
-
-    private Integer distance = Integer.MAX_VALUE;
-
-    private Map<Node, Integer> adjacentNodes = new HashMap<>();
-
-    public Node(String name) {
-        this.name = name;
-    }
-
-    public void addDestination(Node destination, int distance) {
-        adjacentNodes.put(destination, distance);
-    }
-
-    public String getName() {
-        return name;
-    }
-
-    public void setName(String name) {
-        this.name = name;
-    }
-
-    public Map<Node, Integer> getAdjacentNodes() {
-        return adjacentNodes;
-    }
-
-    public void setAdjacentNodes(Map<Node, Integer> adjacentNodes) {
-        this.adjacentNodes = adjacentNodes;
-    }
-
-    public Integer getDistance() {
-        return distance;
-    }
-
-    public void setDistance(Integer distance) {
-        this.distance = distance;
-    }
-
-    public List<Node> getShortestPath() {
-        return shortestPath;
-    }
-
-    public void setShortestPath(LinkedList<Node> shortestPath) {
-        this.shortestPath = shortestPath;
-    }
-
-}
+package com.baeldung.algorithms.ga.dijkstra;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+public class Node {
+
+    private String name;
+
+    private LinkedList<Node> shortestPath = new LinkedList<>();
+
+    private Integer distance = Integer.MAX_VALUE;
+
+    private Map<Node, Integer> adjacentNodes = new HashMap<>();
+
+    public Node(String name) {
+        this.name = name;
+    }
+
+    public void addDestination(Node destination, int distance) {
+        adjacentNodes.put(destination, distance);
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Map<Node, Integer> getAdjacentNodes() {
+        return adjacentNodes;
+    }
+
+    public void setAdjacentNodes(Map<Node, Integer> adjacentNodes) {
+        this.adjacentNodes = adjacentNodes;
+    }
+
+    public Integer getDistance() {
+        return distance;
+    }
+
+    public void setDistance(Integer distance) {
+        this.distance = distance;
+    }
+
+    public List<Node> getShortestPath() {
+        return shortestPath;
+    }
+
+    public void setShortestPath(LinkedList<Node> shortestPath) {
+        this.shortestPath = shortestPath;
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/primechecker/BigIntegerPrimeChecker.java

@@ -0,0 +1,13 @@
+package com.baeldung.algorithms.primechecker;
+
+import java.math.BigInteger;
+
+public class BigIntegerPrimeChecker implements PrimeChecker{
+
+    @Override
+    public boolean isPrime(int number) {
+        BigInteger bigInt = BigInteger.valueOf(number);
+        return bigInt.isProbablePrime(100);
+    }
+
+}

algorithms/src/main/java/com/baeldung/algorithms/primechecker/BruteForcePrimeChecker.java

@@ -0,0 +1,13 @@
+package com.baeldung.algorithms.primechecker;
+
+import java.util.stream.IntStream;
+
+public class BruteForcePrimeChecker implements PrimeChecker{
+
+    @Override
+    public boolean isPrime(int number) {
+        return IntStream.range(2, number).noneMatch(n -> (number % n == 0));
+    }
+
+    
+}       

algorithms/src/main/java/com/baeldung/algorithms/primechecker/OptimisedPrimeChecker.java

@@ -0,0 +1,14 @@
+package com.baeldung.algorithms.primechecker;
+
+import java.util.stream.IntStream;
+
+public class OptimisedPrimeChecker implements PrimeChecker{
+
+    @Override
+    public boolean isPrime(int number) {
+        return IntStream.range(2, (int)Math.sqrt(number) + 1)
+            .noneMatch(n -> (number % n == 0));
+    }
+
+    
+}

algorithms/src/main/java/com/baeldung/algorithms/primechecker/PrimeChecker.java

@@ -0,0 +1,6 @@
+package com.baeldung.algorithms.primechecker;
+
+public interface PrimeChecker {
+    
+    public boolean isPrime( int number );
+}

algorithms/src/main/java/com/baeldung/algorithms/primechecker/PrimesPrimeChecker.java

@@ -0,0 +1,12 @@
+package com.baeldung.algorithms.primechecker;
+
+import org.apache.commons.math3.primes.Primes;
+
+public class PrimesPrimeChecker implements PrimeChecker{
+
+    @Override
+    public boolean isPrime(int number) {
+        return Primes.isPrime(number);
+    }
+
+}

algorithms/src/main/java/com/baeldung/automata/FiniteStateMachine.java

@@ -5,12 +5,12 @@ package com.baeldung.automata;
  */
 public interface FiniteStateMachine {
 
-	/**
-	 * Follow a transition, switch the state of the machine.
-	 * @param c Char.
-	 * @return A new finite state machine with the new state.
-	 */
-	FiniteStateMachine switchState(final CharSequence c);
+    /**
+     * Follow a transition, switch the state of the machine.
+     * @param c Char.
+     * @return A new finite state machine with the new state.
+     */
+    FiniteStateMachine switchState(final CharSequence c);
 
     /**
      * Is the current state a final one?

algorithms/src/main/java/com/baeldung/automata/RtFiniteStateMachine.java

@@ -6,25 +6,25 @@ package com.baeldung.automata;
  */
 public final class RtFiniteStateMachine implements FiniteStateMachine {
 
-	/**
-	 * Current state.
-	 */
-	private State current;
+    /**
+     * Current state.
+     */
+    private State current;
 
-	/**
-	 * Ctor.
-	 * @param initial Initial state of this machine.
-	 */
-	public RtFiniteStateMachine(final State initial) {
-		this.current = initial;
-	}
+    /**
+     * Ctor.
+     * @param initial Initial state of this machine.
+     */
+    public RtFiniteStateMachine(final State initial) {
+        this.current = initial;
+    }
 
-	public FiniteStateMachine switchState(final CharSequence c) {
-		return new RtFiniteStateMachine(this.current.transit(c));
-	}
+    public FiniteStateMachine switchState(final CharSequence c) {
+        return new RtFiniteStateMachine(this.current.transit(c));
+    }
 
-	public boolean canStop() {
-		return this.current.isFinal();
-	}
+    public boolean canStop() {
+        return this.current.isFinal();
+    }
 
 }

algorithms/src/main/java/com/baeldung/automata/RtState.java

@@ -21,22 +21,22 @@ public final class RtState implements State {
     }
 
     public State transit(final CharSequence c) {
-        for(final Transition t : this.transitions) {
-            if(t.isPossible(c)) {
-                return t.state();
-            }
-        }
-        throw new IllegalArgumentException("Input not accepted: " + c);
+        return transitions
+          .stream()
+          .filter(t -> t.isPossible(c))
+          .map(Transition::state)
+          .findAny()
+          .orElseThrow(() -> new IllegalArgumentException("Input not accepted: " + c));
     }
 
     public boolean isFinal() {
         return this.isFinal;
     }
 
-	@Override
-	public State with(Transition tr) {
-		this.transitions.add(tr);
-		return this;
-	}
+    @Override
+    public State with(Transition tr) {
+        this.transitions.add(tr);
+        return this;
+    }
 
 }

algorithms/src/main/java/com/baeldung/automata/RtTransition.java

@@ -6,26 +6,26 @@ package com.baeldung.automata;
  */
 public final class RtTransition implements Transition {
 
-	private String rule;
-	private State next;
-	
-	/**
-	 * Ctor.
-	 * @param rule Rule that a character has to meet 
-	 *  in order to get to the next state.  
-	 * @param next Next state.
-	 */
-	public RtTransition (String rule, State next) {
-		this.rule = rule;
-		this.next = next;
-	}
-	
-	public State state() {
-		return this.next;
-	}
+    private String rule;
+    private State next;
+    
+    /**
+     * Ctor.
+     * @param rule Rule that a character has to meet 
+     *  in order to get to the next state.  
+     * @param next Next state.
+     */
+    public RtTransition (String rule, State next) {
+        this.rule = rule;
+        this.next = next;
+    }
+    
+    public State state() {
+        return this.next;
+    }
 
-	public boolean isPossible(CharSequence c) {
-		return this.rule.equalsIgnoreCase(String.valueOf(c));
-	}
+    public boolean isPossible(CharSequence c) {
+        return this.rule.equalsIgnoreCase(String.valueOf(c));
+    }
 
 }

algorithms/src/main/java/com/baeldung/automata/State.java

@@ -5,12 +5,12 @@ package com.baeldung.automata;
  */
 public interface State {
 
-	/**
-	 * Add a Transition to this state.
-	 * @param tr Given transition.
-	 * @return Modified State.
-	 */
-	State with(final Transition tr);
+    /**
+     * Add a Transition to this state.
+     * @param tr Given transition.
+     * @return Modified State.
+     */
+    State with(final Transition tr);
 
     /**
      * Follow one of the transitions, to get 

algorithms/src/main/java/com/baeldung/automata/Transition.java

@@ -5,16 +5,16 @@ package com.baeldung.automata;
  */
 public interface Transition {
 
-	/**
-	 * Is the transition possible with the given character?
-	 * @param c char.
-	 * @return true or false.
-	 */
-	boolean isPossible(final CharSequence c);
+    /**
+     * Is the transition possible with the given character?
+     * @param c char.
+     * @return true or false.
+     */
+    boolean isPossible(final CharSequence c);
 
-	/**
-	 * The state to which this transition leads.
-	 * @return State.
-	 */
+    /**
+     * The state to which this transition leads.
+     * @return State.
+     */
     State state();
 }

algorithms/src/test/java/algorithms/RtFiniteStateMachineTest.java

@@ -9,74 +9,74 @@ import com.baeldung.automata.*;
  */
 public final class RtFiniteStateMachineTest {
 
-	@Test
+    @Test
     public void acceptsSimplePair() {
-    	String json = "{\"key\":\"value\"}";
-    	FiniteStateMachine machine = this.buildJsonStateMachine();
-    	for (int i=0;i<json.length();i++) {
-    	    machine = machine.switchState(String.valueOf(json.charAt(i)));
-    	}
-    	assertTrue(machine.canStop());
+        String json = "{\"key\":\"value\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i=0;i<json.length();i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+        assertTrue(machine.canStop());
     }
-	@Test
+    @Test
     public void acceptsMorePairs() {
-    	String json = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
-    	FiniteStateMachine machine = this.buildJsonStateMachine();
-    	for (int i=0;i<json.length();i++) {
-    	    machine = machine.switchState(String.valueOf(json.charAt(i)));
-    	}
-    	assertTrue(machine.canStop());
+        String json = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i=0;i<json.length();i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+        assertTrue(machine.canStop());
     }
-	
-	@Test(expected = IllegalArgumentException.class)
+    
+    @Test(expected = IllegalArgumentException.class)
     public void missingColon() {
-    	String json = "{\"key\"\"value\"}";
-    	FiniteStateMachine machine = this.buildJsonStateMachine();
-    	for (int i=0;i<json.length();i++) {
-    	    machine = machine.switchState(String.valueOf(json.charAt(i)));
-    	}
+        String json = "{\"key\"\"value\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i=0;i<json.length();i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
     }
 
-	/**
-	 * Builds a finite state machine to validate a simple
-	 * Json object.
-	 * @return
-	 */
-	private FiniteStateMachine buildJsonStateMachine() {
-		State first = new RtState();
-    	State second = new RtState();
-    	State third = new RtState();
-    	State fourth = new RtState();
-    	State fifth = new RtState();
-    	State sixth = new RtState();
-    	State seventh = new RtState();
-    	State eighth = new RtState(true);
+    /**
+     * Builds a finite state machine to validate a simple
+     * Json object.
+     * @return
+     */
+    private FiniteStateMachine buildJsonStateMachine() {
+        State first = new RtState();
+        State second = new RtState();
+        State third = new RtState();
+        State fourth = new RtState();
+        State fifth = new RtState();
+        State sixth = new RtState();
+        State seventh = new RtState();
+        State eighth = new RtState(true);
 
-    	first.with(new RtTransition("{", second));
-    	second.with(new RtTransition("\"", third));
-    	//Add transitions with chars 0-9 and a-z
-    	for (int i = 0; i < 26; i++) {
-    		if(i<10) {
-        	    third = third.with(
-            	    new RtTransition(String.valueOf(i), third)
-            	);
-        	    sixth = sixth.with(
-                	new RtTransition(String.valueOf(i), sixth)
+        first.with(new RtTransition("{", second));
+        second.with(new RtTransition("\"", third));
+        //Add transitions with chars 0-9 and a-z
+        for (int i = 0; i < 26; i++) {
+            if(i<10) {
+                third = third.with(
+                    new RtTransition(String.valueOf(i), third)
                 );
-    		}
-    	    third = third.with(
-    	        new RtTransition(String.valueOf((char) ('a' + i)), third)
-    	    );
-    	    sixth = sixth.with(
-        	    new RtTransition(String.valueOf((char) ('a' + i)), sixth)
-        	);
-    	}
-    	third.with(new RtTransition("\"", fourth));
-    	fourth.with(new RtTransition(":", fifth));
-    	fifth.with(new RtTransition("\"", sixth));
-    	sixth.with(new RtTransition("\"", seventh));
-    	seventh.with(new RtTransition(",", second));
-    	seventh.with(new RtTransition("}", eighth));
-    	return new RtFiniteStateMachine(first);
-	}
+                sixth = sixth.with(
+                    new RtTransition(String.valueOf(i), sixth)
+                );
+            }
+            third = third.with(
+                new RtTransition(String.valueOf((char) ('a' + i)), third)
+            );
+            sixth = sixth.with(
+                new RtTransition(String.valueOf((char) ('a' + i)), sixth)
+            );
+        }
+        third.with(new RtTransition("\"", fourth));
+        fourth.with(new RtTransition(":", fifth));
+        fifth.with(new RtTransition("\"", sixth));
+        sixth.with(new RtTransition("\"", seventh));
+        seventh.with(new RtTransition(",", second));
+        seventh.with(new RtTransition("}", eighth));
+        return new RtFiniteStateMachine(first);
+    }
 }

algorithms/src/test/java/com/baeldung/algorithms/primechecker/BigIntegerPrimeCheckerTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.primechecker;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import com.baeldung.algorithms.primechecker.BigIntegerPrimeChecker;
+import com.baeldung.algorithms.primechecker.PrimeChecker;
+
+public class BigIntegerPrimeCheckerTest {
+
+    PrimeChecker primeChecker = new BigIntegerPrimeChecker();
+    
+    @Test
+    public void givenPrimeNumber_whenCheckIsPrime_thenTrue(){
+        assertTrue(primeChecker.isPrime(13));
+        assertTrue(primeChecker.isPrime(1009));
+    }
+    
+    @Test
+    public void givenNonPrimeNumber_whenCheckIsPrime_thenFalse(){
+        assertTrue(!primeChecker.isPrime(50));
+        assertTrue(!primeChecker.isPrime(1001));
+    }
+    
+}

algorithms/src/test/java/com/baeldung/algorithms/primechecker/BruteForcePrimeCheckerTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.algorithms.primechecker;
+
+import org.junit.Test;
+
+import com.baeldung.algorithms.primechecker.BruteForcePrimeChecker;
+
+import static org.junit.Assert.*;
+
+public class BruteForcePrimeCheckerTest {
+
+    BruteForcePrimeChecker primeChecker = new BruteForcePrimeChecker();
+    
+    @Test
+    public void givenPrimeNumber_whenCheckIsPrime_thenTrue(){
+        assertTrue(primeChecker.isPrime(13));
+        assertTrue(primeChecker.isPrime(1009));
+    }
+    
+    @Test
+    public void givenNonPrimeNumber_whenCheckIsPrime_thenFalse(){
+        assertTrue(!primeChecker.isPrime(50));
+        assertTrue(!primeChecker.isPrime(1001));
+    }
+    
+    
+    
+}

algorithms/src/test/java/com/baeldung/algorithms/primechecker/OptimisedPrimeCheckerTest.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.primechecker;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import com.baeldung.algorithms.primechecker.OptimisedPrimeChecker;
+import com.baeldung.algorithms.primechecker.PrimeChecker;
+
+public class OptimisedPrimeCheckerTest {
+
+    PrimeChecker primeChecker = new OptimisedPrimeChecker();
+    
+    @Test
+    public void givenPrimeNumber_whenCheckIsPrime_thenTrue(){
+        assertTrue(primeChecker.isPrime(13));
+        assertTrue(primeChecker.isPrime(1009));
+    }
+    
+    @Test
+    public void givenNonPrimeNumber_whenCheckIsPrime_thenFalse(){
+        assertTrue(!primeChecker.isPrime(50));
+        assertTrue(!primeChecker.isPrime(1001));
+    }
+    
+}

algorithms/src/test/java/com/baeldung/algorithms/primechecker/PrimesPrimeCheckerTest.java

@@ -0,0 +1,25 @@
+package com.baeldung.algorithms.primechecker;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import com.baeldung.algorithms.primechecker.PrimeChecker;
+import com.baeldung.algorithms.primechecker.PrimesPrimeChecker;
+
+public class PrimesPrimeCheckerTest {
+    PrimeChecker primeChecker = new PrimesPrimeChecker();
+
+    @Test
+    public void givenPrimeNumber_whenCheckIsPrime_thenTrue() {
+        assertTrue(primeChecker.isPrime(13));
+        assertTrue(primeChecker.isPrime(1009));
+    }
+
+    @Test
+    public void givenNonPrimeNumber_whenCheckIsPrime_thenFalse() {
+        assertTrue(!primeChecker.isPrime(50));
+        assertTrue(!primeChecker.isPrime(1001));
+    }
+
+}

apache-poi/.gitignore

@@ -1 +1,3 @@
 *.docx
+temp.xls
+temp.xlsx

aws/README.md

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [AWS Lambda Using DynamoDB With Java](http://www.baeldung.com/aws-lambda-dynamodb-java)

axon/README.md

@@ -0,0 +1,3 @@
+### Relevant articles
+
+- [A Guide to the Axon Framework](http://www.baeldung.com/axon-cqrs-event-sourcing)

core-java-9/README.md

@@ -8,4 +8,7 @@
 - [Java 9 Stream API Improvements](http://www.baeldung.com/java-9-stream-api)
 - [Java 9 Convenience Factory Methods for Collections](http://www.baeldung.com/java-9-collections-factory-methods) 
 - [New Stream Collectors in Java 9](http://www.baeldung.com/java9-stream-collectors)
-- [Java 9 CompletableFuture API Improvements](http://www.baeldung.com/java9-completablefuture-api-improvements/)
+- [Java 9 CompletableFuture API Improvements](http://www.baeldung.com/java9-completablefuture-api-improvements/)
+- [Spring Security – Redirect to the Previous URL After Login](http://www.baeldung.com/spring-security-redirect-login)
+- [Java 9 Process API Improvements](http://www.baeldung.com/java-9-process-api)
+- [Introduction to Java 9 StackWalking API](http://www.baeldung.com/java-9-stackwalking-api)