Merge branch 'master' of https://github.com/chris9408/tutorials into feature/selenium-cookies

algorithms-miscellaneous-5/README.md

@@ -10,4 +10,6 @@ This module contains articles about algorithms. Some classes of algorithms, e.g.
 - [Find If Two Numbers Are Relatively Prime in Java](https://www.baeldung.com/java-two-relatively-prime-numbers)
 - [Knapsack Problem Implementation in Java](https://www.baeldung.com/java-knapsack)
 - [How to Determine if a Binary Tree is Balanced](https://www.baeldung.com/java-balanced-binary-tree)
+- [The Caesar Cipher in Java](https://www.baeldung.com/java-caesar-cipher)
+- [Overview of Combinatorial Problems in Java](https://www.baeldung.com/java-combinatorial-algorithms)
 - More articles: [[<-- prev]](/../algorithms-miscellaneous-4)

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/integerstreammedian/MedianOfIntegerStream.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.integerstreammedian;
+
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+import static java.util.Comparator.reverseOrder;
+
+public class MedianOfIntegerStream {
+
+    private Queue<Integer> minHeap, maxHeap;
+
+    MedianOfIntegerStream() {
+        minHeap = new PriorityQueue<>();
+        maxHeap = new PriorityQueue<>(reverseOrder());
+    }
+
+    void add(int num) {
+        if (!minHeap.isEmpty() && num < minHeap.peek()) {
+            maxHeap.offer(num);
+            if (maxHeap.size() > minHeap.size() + 1) {
+                minHeap.offer(maxHeap.poll());
+            }
+        } else {
+            minHeap.offer(num);
+            if (minHeap.size() > maxHeap.size() + 1) {
+                maxHeap.offer(minHeap.poll());
+            }
+        }
+    }
+
+    double getMedian() {
+        int median;
+        if (minHeap.size() < maxHeap.size()) {
+            median = maxHeap.peek();
+        } else if (minHeap.size() > maxHeap.size()) {
+            median = minHeap.peek();
+        } else {
+            median = (minHeap.peek() + maxHeap.peek()) / 2;
+        }
+        return median;
+    }
+}

algorithms-miscellaneous-5/src/main/java/com/baeldung/algorithms/integerstreammedian/MedianOfIntegerStream2.java

@@ -0,0 +1,36 @@
+package com.baeldung.algorithms.integerstreammedian;
+
+import java.util.PriorityQueue;
+import java.util.Queue;
+
+import static java.util.Comparator.reverseOrder;
+
+public class MedianOfIntegerStream2 {
+
+    private Queue<Integer> minHeap, maxHeap;
+
+    MedianOfIntegerStream2() {
+        minHeap = new PriorityQueue<>();
+        maxHeap = new PriorityQueue<>(reverseOrder());
+    }
+
+    void add(int num) {
+        if (minHeap.size() == maxHeap.size()) {
+            maxHeap.offer(num);
+            minHeap.offer(maxHeap.poll());
+        } else {
+            minHeap.offer(num);
+            maxHeap.offer(minHeap.poll());
+        }
+    }
+
+    double getMedian() {
+        int median;
+        if (minHeap.size() > maxHeap.size()) {
+            median = minHeap.peek();
+        } else {
+            median = (minHeap.peek() + maxHeap.peek()) / 2;
+        }
+        return median;
+    }
+}

algorithms-miscellaneous-5/src/test/java/com/baeldung/algorithms/integerstreammedian/MedianOfIntegerStreamUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.algorithms.integerstreammedian;
+
+import org.junit.Test;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+public class MedianOfIntegerStreamUnitTest {
+
+    @Test
+    public void givenStreamOfIntegers_whenAnElementIsRead_thenMedianChangesWithApproach1() {
+        MedianOfIntegerStream mis = new MedianOfIntegerStream();
+        for (Map.Entry<Integer, Double> e : testcaseFixture().entrySet()) {
+            mis.add(e.getKey());
+            assertEquals(e.getValue(), (Double) mis.getMedian());
+        }
+    }
+
+    @Test
+    public void givenStreamOfIntegers_whenAnElementIsRead_thenMedianChangesWithApproach2() {
+        MedianOfIntegerStream2 mis = new MedianOfIntegerStream2();
+        for (Map.Entry<Integer, Double> e : testcaseFixture().entrySet()) {
+            mis.add(e.getKey());
+            assertEquals(e.getValue(), (Double) mis.getMedian());
+        }
+    }
+
+    private Map<Integer, Double> testcaseFixture() {
+        return new LinkedHashMap<Integer, Double>() {{
+            put(1, 1d);
+            put(7, 4d);
+            put(5, 5d);
+            put(8, 6d);
+            put(3, 5d);
+            put(9, 6d);
+            put(4, 5d);
+        }};
+    }
+}

core-java-modules/core-java-11/README.md

@@ -12,3 +12,4 @@ This module contains articles about Java 11 core features
 - [An Introduction to Epsilon GC: A No-Op Experimental Garbage Collector](https://www.baeldung.com/jvm-epsilon-gc-garbage-collector)
 - [Guide to jlink](https://www.baeldung.com/jlink)
 - [Negate a Predicate Method Reference with Java 11](https://www.baeldung.com/java-negate-predicate-method-reference)
+- [Benchmark JDK Collections vs Eclipse Collections](https://www.baeldung.com/jdk-collections-vs-eclipse-collections)

core-java-modules/core-java-11/src/test/java/com/baeldung/patternreuse/PatternJava11UnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.patternreuse;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class PatternJava11UnitTest {
+
+    @Test
+    public void givenPreCompiledPattern_whenCallAsMatchPredicate_thenReturnMatchPredicateToMatchesPattern() {
+        List<String> namesToValidate = Arrays.asList("Fabio Silva", "Fabio Luis Silva");
+        Pattern firstLastNamePreCompiledPattern = Pattern.compile("[a-zA-Z]{3,} [a-zA-Z]{3,}");
+
+        Predicate<String> patternAsMatchPredicate = firstLastNamePreCompiledPattern.asMatchPredicate();
+        List<String> validatedNames = namesToValidate.stream()
+                .filter(patternAsMatchPredicate)
+                .collect(Collectors.toList());
+
+        assertTrue(validatedNames.contains("Fabio Silva"));
+        assertFalse(validatedNames.contains("Fabio Luis Silva"));
+    }
+}

core-java-modules/core-java-date-operations/src/test/java/com/baeldung/jvmtimezone/ModifyDefaultTimezoneUnitTest.java

@@ -1,9 +1,8 @@
-package com.baeldung.timezone;
+package com.baeldung.jvmtimezone;
 
 import org.junit.Test;
 
 import java.util.Calendar;
-import java.util.Date;
 import java.util.TimeZone;
 
 import static org.junit.Assert.assertEquals;
@@ -13,9 +12,7 @@ public class ModifyDefaultTimezoneUnitTest {
     @Test
     public void givenDefaultTimezoneSet_thenDateTimezoneIsCorrect() {
         TimeZone.setDefault(TimeZone.getTimeZone("Portugal"));
-        Date date = new Date();
         Calendar calendar = Calendar.getInstance();
-        calendar.setTime(date);
         assertEquals(calendar.getTimeZone(), TimeZone.getTimeZone("Portugal"));
     }
 

core-java-modules/core-java-date-operations/src/test/java/com/baeldung/jvmtimezone/ModifyTimezonePropertyUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.timezone;
+package com.baeldung.jvmtimezone;
 
 import org.junit.After;
 import org.junit.Before;
@@ -14,7 +14,7 @@ public class ModifyTimezonePropertyUnitTest {
 
     @Before
     public void setup() {
-        System.setProperty("user.timezone", "IST");
+        System.setProperty("user.timezone", "Asia/Kolkata");
         TimeZone.setDefault(null);
     }
 
@@ -25,10 +25,8 @@ public class ModifyTimezonePropertyUnitTest {
 
     @Test
     public void givenTimezonePropertySet_thenDateTimezoneIsCorrect() {
-        Date date = new Date();
         Calendar calendar = Calendar.getInstance();
-        calendar.setTime(date);
-        assertEquals(calendar.getTimeZone(), TimeZone.getTimeZone("IST"));
+        assertEquals(calendar.getTimeZone(), TimeZone.getTimeZone("Asia/Kolkata"));
     }
 
 }

core-java-modules/core-java-lang-math/README.md

@@ -7,3 +7,5 @@
 - [Java 8 Unsigned Arithmetic Support](https://www.baeldung.com/java-unsigned-arithmetic)
 - [How to Separate Double into Integer and Decimal Parts](https://www.baeldung.com/java-separate-double-into-integer-decimal-parts)
 - [The strictfp Keyword in Java](https://www.baeldung.com/java-strictfp)
+- [Basic Calculator in Java](https://www.baeldung.com/java-basic-calculator)
+- [Overflow and Underflow in Java](https://www.baeldung.com/java-overflow-underflow)

core-java-modules/core-java-lang-operators/README.md

@@ -11,4 +11,5 @@ This module contains articles about Java operators
 - [Java Compound Operators](https://www.baeldung.com/java-compound-operators)
 - [The XOR Operator in Java](https://www.baeldung.com/java-xor-operator)
 - [Java Bitwise Operators](https://www.baeldung.com/java-bitwise-operators)
+- [Bitwise & vs Logical && Operators](https://www.baeldung.com/bitwise-vs-logical-operators/)
 

core-java-modules/core-java-lang-operators/src/test/java/com/baeldung/andoperators/BitwiseAndLogicalANDOperatorsUnitTest.java

@@ -0,0 +1,71 @@
+package com.baeldung.andoperators;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.Assert.*;
+
+public class BitwiseAndLogicalANDOperatorsUnitTest {
+
+    @Test
+    public void givenTwoTrueBooleans_whenBitwiseAndOperator_thenTrue() {
+        boolean trueBool = true;
+        boolean anotherTrueBool = true;
+        boolean trueANDTrue = trueBool & anotherTrueBool;
+        assertTrue(trueANDTrue);
+    }
+
+    @Test
+    public void givenOneFalseAndOneTrueBooleans_whenBitwiseAndOperator_thenFalse() {
+        boolean trueBool = true;
+        boolean falseBool = false;
+        boolean trueANDFalse = trueBool & falseBool;
+        assertFalse(trueANDFalse);
+    }
+
+    @Test
+    public void givenTwoFalseBooleans_whenBitwiseAndOperator_thenFalse() {
+        boolean falseBool = false;
+        boolean anotherFalseBool = false;
+        boolean falseANDFalse = falseBool & anotherFalseBool;
+        assertFalse(falseANDFalse);
+    }
+
+    @Test
+    public void givenTwoIntegers_whenBitwiseAndOperator_thenNewDecimalNumber() {
+        int six = 6;
+        int five = 5;
+        int shouldBeFour = six & five;
+        assertEquals(4, shouldBeFour);
+    }
+
+    @Test
+    public void givenTwoTrueBooleans_whenLogicalAndOperator_thenTrue() {
+        boolean trueBool = true;
+        boolean anotherTrueBool = true;
+        boolean trueANDTrue = trueBool && anotherTrueBool;
+        assertTrue(trueANDTrue);
+    }
+
+    @Test
+    public void givenOneFalseAndOneTrueBooleans_whenLogicalAndOperator_thenFalse() {
+        boolean trueBool = true;
+        boolean falseBool = false;
+        boolean trueANDFalse = trueBool && falseBool;
+        assertFalse(trueANDFalse);
+    }
+
+    @Test
+    public void givenTwoFalseBooleans_whenLogicalAndOperator_thenFalse() {
+        boolean falseBool = false;
+        boolean anotherFalseBool = false;
+        boolean falseANDFalse = falseBool && anotherFalseBool;
+        assertFalse(falseANDFalse);
+    }
+
+    @Test
+    public void givenTwoFalseExpressions_whenLogicalAndOperator_thenShortCircuitFalse() {
+        boolean shortCircuitResult = (2<1) && (4<5);
+        assertFalse(shortCircuitResult);
+    }
+
+}

core-java-modules/core-java-lang-syntax-2/src/main/java/com/baeldung/core/operators/notoperator/NotOperator.java

@@ -0,0 +1,99 @@
+package com.baeldung.core.operators.notoperator;
+
+/**
+ * Examples used in the article `Using the Not Operator in If Conditions in Java`.
+ */
+public class NotOperator {
+
+    public static void ifElseStatementExample() {
+        boolean isValid = true;
+
+        if (isValid) {
+            System.out.println("Valid");
+        } else {
+            System.out.println("Invalid");
+        }
+    }
+
+    public static void checkIsValidIsFalseWithEmptyIfBlock() {
+        boolean isValid = true;
+
+        if (isValid) {
+
+        } else {
+            System.out.println("Invalid");
+        }
+    }
+
+    public static void checkIsValidIsFalseWithJustTheIfBlock() {
+        boolean isValid = true;
+
+        if (isValid == false) {
+            System.out.println("Invalid");
+        }
+    }
+
+    public static void checkIsValidIsFalseWithTheNotOperator() {
+        boolean isValid = true;
+
+        if (!isValid) {
+            System.out.println("Invalid");
+        }
+    }
+
+    public static void notOperatorWithBooleanValueAsOperand() {
+        System.out.println(!true);   // prints false
+        System.out.println(!false);  // prints true
+        System.out.println(!!false); // prints false
+    }
+
+    public static void applyNotOperatorToAnExpression_example1() {
+        int count = 2;
+
+        System.out.println(!(count > 2));  // prints true
+        System.out.println(!(count <= 2)); // prints false
+    }
+
+    public static void applyNotOperatorToAnExpression_LogicalOperators() {
+        boolean x = true;
+        boolean y = false;
+
+        System.out.println(!(x && y));  // prints true
+        System.out.println(!(x || y));  // prints false
+    }
+
+    public static void precedence_example() {
+        boolean x = true;
+        boolean y = false;
+
+        System.out.println(!x && y);   // prints false
+        System.out.println(!(x && y)); // prints true
+    }
+
+    public static void pitfalls_ComplexConditionsExample() {
+        int count = 9;
+        int total = 100;
+
+        if (!(count >= 10 || total >= 1000)) {
+            System.out.println("Some more work to do");
+        }
+    }
+
+    public static void pitfalls_simplifyComplexConditionsByReversingLogicExample() {
+        int count = 9;
+        int total = 100;
+
+        if (count < 10 && total < 1000) {
+            System.out.println("Some more work to do");
+        }
+    }
+
+    public static void exitEarlyExample() {
+        boolean isValid = false;
+
+        if(!isValid) {
+            throw new IllegalArgumentException("Invalid input");
+        }
+        // Code to execute when isValid == true goes here
+    }
+}

core-java-modules/core-java-strings/src/test/java/com/baeldung/randomstrings/RandomStringsUnitTest.java

@@ -1,72 +1,103 @@
-package com.baeldung.randomstrings;
-
-import org.apache.commons.lang3.RandomStringUtils;
-import org.junit.Test;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.nio.charset.Charset;
-import java.util.Random;
-
-public class RandomStringsUnitTest {
-
-    private static final Logger LOG = LoggerFactory.getLogger(RandomStringsUnitTest.class);
-
-    @Test
-    public void givenUsingPlainJava_whenGeneratingRandomStringUnbounded_thenCorrect() {
-        final byte[] array = new byte[7]; // length is bounded by 7
-        new Random().nextBytes(array);
-        final String generatedString = new String(array, Charset.forName("UTF-8"));
-
-        LOG.debug(generatedString);
-    }
-
-    @Test
-    public void givenUsingPlainJava_whenGeneratingRandomStringBounded_thenCorrect() {
-        final int leftLimit = 97; // letter 'a'
-        final int rightLimit = 122; // letter 'z'
-        final int targetStringLength = 10;
-        final Random random = new Random();
-        final StringBuilder buffer = new StringBuilder(targetStringLength);
-
-        for (int i = 0; i < targetStringLength; i++) {
-            final int randomLimitedInt = leftLimit + (int) (random.nextFloat() * (rightLimit - leftLimit + 1));
-            buffer.append((char) randomLimitedInt);
-        }
-        final String generatedString = buffer.toString();
-
-        LOG.debug(generatedString);
-    }
-
-    @Test
-    public void givenUsingApache_whenGeneratingRandomString_thenCorrect() {
-        final String generatedString = RandomStringUtils.random(10);
-
-        LOG.debug(generatedString);
-    }
-
-    @Test
-    public void givenUsingApache_whenGeneratingRandomAlphabeticString_thenCorrect() {
-        final String generatedString = RandomStringUtils.randomAlphabetic(10);
-
-        LOG.debug(generatedString);
-    }
-
-    @Test
-    public void givenUsingApache_whenGeneratingRandomAlphanumericString_thenCorrect() {
-        final String generatedString = RandomStringUtils.randomAlphanumeric(10);
-
-        LOG.debug(generatedString);
-    }
-
-    @Test
-    public void givenUsingApache_whenGeneratingRandomStringBounded_thenCorrect() {
-        final int length = 10;
-        final boolean useLetters = true;
-        final boolean useNumbers = false;
-        final String generatedString = RandomStringUtils.random(length, useLetters, useNumbers);
-
-        LOG.debug(generatedString);
-    }
-
-}
+package com.baeldung.randomstrings;
+
+import org.apache.commons.lang3.RandomStringUtils;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.nio.charset.Charset;
+import java.util.Random;
+
+public class RandomStringsUnitTest {
+
+    private static final Logger LOG = LoggerFactory.getLogger(RandomStringsUnitTest.class);
+
+    @Test
+    public void givenUsingPlainJava_whenGeneratingRandomStringUnbounded_thenCorrect() {
+        byte[] array = new byte[7]; // length is bounded by 7
+        new Random().nextBytes(array);
+        String generatedString = new String(array, Charset.forName("UTF-8"));
+
+        LOG.debug(generatedString);
+    }
+
+    @Test
+    public void givenUsingPlainJava_whenGeneratingRandomStringBounded_thenCorrect() {
+        int leftLimit = 97; // letter 'a'
+        int rightLimit = 122; // letter 'z'
+        int targetStringLength = 10;
+        Random random = new Random();
+        StringBuilder buffer = new StringBuilder(targetStringLength);
+
+        for (int i = 0; i < targetStringLength; i++) {
+            int randomLimitedInt = leftLimit + (int) (random.nextFloat() * (rightLimit - leftLimit + 1));
+            buffer.append((char) randomLimitedInt);
+        }
+        String generatedString = buffer.toString();
+
+        LOG.debug(generatedString);
+    }
+
+    @Test
+    public void givenUsingJava8_whenGeneratingRandomAlphabeticString_thenCorrect() {
+        int leftLimit = 97; // letter 'a'
+        int rightLimit = 122; // letter 'z'
+        int targetStringLength = 10;
+        Random random = new Random();
+
+        String generatedString = random.ints(leftLimit, rightLimit + 1)
+            .limit(targetStringLength)
+            .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
+            .toString();
+
+        LOG.debug(generatedString);
+    }
+
+    @Test
+    public void givenUsingJava8_whenGeneratingRandomAlphanumericString_thenCorrect() {
+        int leftLimit = 48; // numeral '0'
+        int rightLimit = 122; // letter 'z'
+        int targetStringLength = 10;
+        Random random = new Random();
+
+        String generatedString = random.ints(leftLimit, rightLimit + 1)
+            .filter(i -> (i <= 57 || i >= 65) && (i <= 90 || i >= 97))
+            .limit(targetStringLength)
+            .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
+            .toString();
+
+        LOG.debug(generatedString);
+    }
+
+    @Test
+    public void givenUsingApache_whenGeneratingRandomString_thenCorrect() {
+        String generatedString = RandomStringUtils.random(10);
+
+        LOG.debug(generatedString);
+    }
+
+    @Test
+    public void givenUsingApache_whenGeneratingRandomAlphabeticString_thenCorrect() {
+        String generatedString = RandomStringUtils.randomAlphabetic(10);
+
+        LOG.debug(generatedString);
+    }
+
+    @Test
+    public void givenUsingApache_whenGeneratingRandomAlphanumericString_thenCorrect() {
+        String generatedString = RandomStringUtils.randomAlphanumeric(10);
+
+        LOG.debug(generatedString);
+    }
+
+    @Test
+    public void givenUsingApache_whenGeneratingRandomStringBounded_thenCorrect() {
+        int length = 10;
+        boolean useLetters = true;
+        boolean useNumbers = false;
+        String generatedString = RandomStringUtils.random(length, useLetters, useNumbers);
+
+        LOG.debug(generatedString);
+    }
+
+}

core-java-modules/core-java-text/pom.xml

@@ -14,6 +14,19 @@
         <relativePath>../../parent-java</relativePath>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-core</artifactId>
+            <version>${jmh-core.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jmh</groupId>
+            <artifactId>jmh-generator-annprocess</artifactId>
+            <version>${jmh-core.version}</version>
+        </dependency>
+    </dependencies>
+
     <build>
         <finalName>core-java-text</finalName>
         <resources>

core-java-modules/core-java-text/src/main/java/com/baeldung/patternreuse/PatternPerformanceComparison.java

@@ -0,0 +1,92 @@
+package com.baeldung.patternreuse;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.infra.Blackhole;
+import org.openjdk.jmh.runner.RunnerException;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@Fork(value = 1, warmups = 1)
+@Warmup(iterations = 5)
+@State(Scope.Benchmark)
+public class PatternPerformanceComparison {
+
+    private static final String PATTERN = "\\d*[02468]";
+    private static List<String> values;
+
+    private static Matcher matcherFromPreCompiledPattern;
+    private static Pattern preCompiledPattern;
+
+    public static void main(String[] args) throws IOException, RunnerException {
+        org.openjdk.jmh.Main.main(args);
+    }
+
+    @Benchmark
+    public void matcherFromPreCompiledPatternResetMatches(Blackhole bh) {
+        //With pre-compiled pattern and reusing the matcher
+        // 1 Pattern object created
+        // 1 Matcher objects created
+        for (String value : values) {
+            bh.consume(matcherFromPreCompiledPattern.reset(value).matches());
+        }
+    }
+
+    @Benchmark
+    public void preCompiledPatternMatcherMatches(Blackhole bh) {
+        // With pre-compiled pattern
+        // 1         Pattern object created
+        // 5_000_000 Matcher objects created
+        for (String value : values) {
+            bh.consume(preCompiledPattern.matcher(value).matches());
+        }
+    }
+
+    @Benchmark
+    public void patternCompileMatcherMatches(Blackhole bh) {
+        // Above approach "Pattern.matches(PATTERN, value)" makes this internally
+        // 5_000_000 Pattern objects created
+        // 5_000_000 Matcher objects created
+        for (String value : values) {
+            bh.consume(Pattern.compile(PATTERN).matcher(value).matches());
+        }
+    }
+
+    @Benchmark
+    public void patternMatches(Blackhole bh) {
+        // Above approach "value.matches(PATTERN)" makes this internally
+        // 5_000_000 Pattern objects created
+        // 5_000_000 Matcher objects created
+        for (String value : values) {
+            bh.consume(Pattern.matches(PATTERN, value));
+        }
+    }
+
+    @Benchmark
+    public void stringMatchs(Blackhole bh) {
+        // 5_000_000 Pattern objects created
+        // 5_000_000 Matcher objects created
+        Instant start = Instant.now();
+        for (String value : values) {
+            bh.consume(value.matches(PATTERN));
+        }
+    }
+
+    @Setup()
+    public void setUp() {
+        preCompiledPattern = Pattern.compile(PATTERN);
+        matcherFromPreCompiledPattern = preCompiledPattern.matcher("");
+
+        values = new ArrayList<>();
+        for (int x = 1; x <= 5_000_000; x++) {
+            values.add(String.valueOf(x));
+        }
+    }
+}

core-java-modules/core-java-text/src/test/java/com/baeldung/patternreuse/PatternUnitTest.java

@@ -0,0 +1,63 @@
+package com.baeldung.patternreuse;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.junit.Assert.*;
+
+public class PatternUnitTest {
+
+    private static final Pattern FIRST_LAST_NAME_PRE_COMPILED_PATTERN = Pattern.compile("[a-zA-Z]{3,} [a-zA-Z]{3,}");
+    private static final Pattern SPLIT_PRE_COMPILED_PATTERN = Pattern.compile("__");
+
+    @Test
+    public void givenPreCompiledPattern_whenCallMatcher_thenReturnAMatcherToMatches() {
+        Matcher matcherName1 = FIRST_LAST_NAME_PRE_COMPILED_PATTERN.matcher("Fabio Silva");
+        Matcher matcherName2 = FIRST_LAST_NAME_PRE_COMPILED_PATTERN.matcher("Mr. Silva");
+
+        boolean matchesName1 = matcherName1.matches();
+        boolean matchesName2 = matcherName2.matches();
+
+        assertTrue(matchesName1);
+        assertFalse(matchesName2);
+    }
+
+    @Test
+    public void givenPreCompiledPattern_whenCallAsPredicate_thenReturnPredicateToFindPatternInTheList() {
+        List<String> namesToValidate = Arrays.asList("Fabio Silva", "Mr. Silva");
+        Predicate<String> patternsAsPredicate = FIRST_LAST_NAME_PRE_COMPILED_PATTERN.asPredicate();
+
+        List<String> validNames = namesToValidate.stream()
+                .filter(patternsAsPredicate)
+                .collect(Collectors.toList());
+
+        assertEquals(1, validNames.size());
+        assertTrue(validNames.contains("Fabio Silva"));
+    }
+
+    @Test
+    public void givenPreCompiledPattern_whenCallSplit_thenReturnArrayWithValuesSplitByThePattern() {
+        String[] textSplit = SPLIT_PRE_COMPILED_PATTERN.split("My_Name__is__Fabio_Silva");
+
+        assertEquals("My_Name", textSplit[0]);
+        assertEquals("is", textSplit[1]);
+        assertEquals("Fabio_Silva", textSplit[2]);
+    }
+
+    @Test
+    public void givenPreCompiledPattern_whenCallSplitAsStream_thenReturnArraySplitByThePattern() {
+        Stream<String> textSplitAsStream = SPLIT_PRE_COMPILED_PATTERN.splitAsStream("My_Name__is__Fabio_Silva");
+        String[] textSplit = textSplitAsStream.toArray(String[]::new);
+
+        assertEquals("My_Name", textSplit[0]);
+        assertEquals("is", textSplit[1]);
+        assertEquals("Fabio_Silva", textSplit[2]);
+    }
+}

intelliJ/remote-debugging/README.adoc

@@ -82,3 +82,4 @@ The following guides may also be helpful:
 * https://spring.io/guides/gs/batch-processing/[Creating a Batch Service]
 
 include::https://raw.githubusercontent.com/spring-guides/getting-started-macros/master/footer.adoc[]
+

jackson-modules/jackson-annotations/pom.xml

@@ -8,22 +8,11 @@
 
     <parent>
         <groupId>com.baeldung</groupId>
-        <artifactId>parent-java</artifactId>
+        <artifactId>jackson-modules</artifactId>
         <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../parent-java</relativePath>
     </parent>
 
     <dependencies>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson.version}</version>
-        </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.dataformat</groupId>
-            <artifactId>jackson-dataformat-xml</artifactId>
-            <version>${jackson.version}</version>
-        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.module</groupId>
             <artifactId>jackson-module-jsonSchema</artifactId>

jackson-modules/jackson-conversions-2/pom.xml

@@ -8,23 +8,11 @@
 
     <parent>
         <groupId>com.baeldung</groupId>
-        <artifactId>parent-java</artifactId>
+        <artifactId>jackson-modules</artifactId>
         <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../parent-java</relativePath>
     </parent>
 
     <dependencies>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson.version}</version>
-        </dependency>
-        <!--jackson for xml -->
-        <dependency>
-            <groupId>com.fasterxml.jackson.dataformat</groupId>
-            <artifactId>jackson-dataformat-xml</artifactId>
-            <version>${jackson.version}</version>
-        </dependency>
         <!-- YAML -->
         <dependency>
             <groupId>com.fasterxml.jackson.dataformat</groupId>

jackson-modules/jackson-conversions/pom.xml

@@ -8,17 +8,11 @@
 
     <parent>
         <groupId>com.baeldung</groupId>
-        <artifactId>parent-java</artifactId>
+        <artifactId>jackson-modules</artifactId>
         <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../parent-java</relativePath>
     </parent>
 
     <dependencies>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson.version}</version>
-        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.datatype</groupId>
             <artifactId>jackson-datatype-joda</artifactId>
@@ -29,12 +23,6 @@
             <artifactId>jackson-datatype-jsr310</artifactId>
             <version>${jackson.version}</version>
         </dependency>
-        <!--jackson for xml -->
-        <dependency>
-            <groupId>com.fasterxml.jackson.dataformat</groupId>
-            <artifactId>jackson-dataformat-xml</artifactId>
-            <version>${jackson.version}</version>
-        </dependency>
     </dependencies>
 
     <build>