Submit all code for code-java-string branch

2022-07-15 13:10:35 -04:00
83 changed files with 3202 additions and 0 deletions
@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile default="true" name="Default" enabled="true" />
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="codebank" />
+        <module name="core-java-collections-list" />
+        <module name="core-java-streams" />
+        <module name="assertion-libraries" />
+        <module name="core-java-io" />
+        <module name="core-java-annotations" />
+        <module name="core-java-8-2" />
+        <module name="core-java-numbers" />
+        <module name="discourse" />
+        <module name="core-java-11-2" />
+        <module name="core-java-strings" />
+        <module name="core-java-11" />
+        <module name="core-java-collections-list-2" />
+        <module name="core-java-collections" />
+        <module name="core-java-datetime-conversion" />
+        <module name="core-java-collections-list-3" />
+        <module name="core-java-8" />
+        <module name="junit-5-basics" />
+        <module name="core-java-collections-3" />
+        <module name="core-java-collections-2" />
+      </profile>
+    </annotationProcessing>
+  </component>
+  <component name="JavacSettings">
+    <option name="ADDITIONAL_OPTIONS_OVERRIDE">
+      <module name="core-java-streams" options="-parameters" />
+    </option>
+  </component>
+</project>
@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding">
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11-2/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11-2/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-11/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8-2/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8-2/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-8/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-annotations/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-annotations/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-2/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-2/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-3/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-3/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-2/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-2/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-3/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list-3/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections-list/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-collections/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-datetime-conversion/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-datetime-conversion/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-io/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-io/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-numbers/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-numbers/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-streams/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-streams/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-strings/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/core-java-strings/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/core-java-modules/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/testing-modules/assertion-libraries/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/testing-modules/assertion-libraries/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/testing-modules/junit-5-basics/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/testing-modules/junit-5-basics/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/testing-modules/junit-5-basics/src/test/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/testing-modules/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/testing-modules/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/toolkits/codebank/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/toolkits/codebank/src/main/resources" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/toolkits/discourse/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/toolkits/discourse/src/main/resources" charset="UTF-8" />
+  </component>
+</project>
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://repo.maven.apache.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+  </component>
+</project>
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ThriftCompiler">
+    <compilers />
+  </component>
+</project>
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
@@ -0,0 +1,21 @@
+package com.ossez.java9.compactstring;
+
+import java.util.List;
+import java.util.stream.IntStream;
+
+import static java.util.stream.Collectors.toList;
+
+public class CompactStringDemo {
+
+    public static void main(String[] args) {
+        long startTime = System.currentTimeMillis();
+        List strings = IntStream.rangeClosed(1, 10_000_000).mapToObj(Integer::toString).collect(toList());
+        long totalTime = System.currentTimeMillis() - startTime;
+        System.out.println("Generated " + strings.size() + " strings in " + totalTime + " ms.");
+
+        startTime = System.currentTimeMillis();
+        String appended = (String) strings.stream().limit(100_000).reduce("", (left, right) -> left.toString() + right.toString());
+        totalTime = System.currentTimeMillis() - startTime;
+        System.out.println("Created string of length " + appended.length() + " in " + totalTime + " ms.");
+    }
+}
@@ -0,0 +1,21 @@
+package com.ossez.localization;
+
+import java.text.ParseException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+
+public class App {
+
+    /**
+     * Runs all available formatter
+     * @throws ParseException 
+     */
+    public static void main(String[] args) {
+        List<Locale> locales = Arrays.asList(new Locale[] { Locale.UK, Locale.ITALY, Locale.FRANCE, Locale.forLanguageTag("pl-PL") });
+        Localization.run(locales);
+        JavaSEFormat.run(locales);
+        ICUFormat.run(locales);
+    }
+
+}
@@ -0,0 +1,29 @@
+package com.ossez.localization;
+
+import com.ibm.icu.text.MessageFormat;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.ResourceBundle;
+
+public class ICUFormat {
+
+    public static String getLabel(Locale locale, Object[] data) {
+        ResourceBundle bundle = ResourceBundle.getBundle("formats", locale);
+        String format = bundle.getString("label-icu");
+        MessageFormat formatter = new MessageFormat(format, locale);
+        return formatter.format(data);
+    }
+
+    public static void run(List<Locale> locales) {
+        System.out.println("ICU formatter");
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Alice", "female", 0 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Alice", "female", 1 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Alice", "female", 2 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Alice", "female", 3 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Bob", "male", 0 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Bob", "male", 1 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Bob", "male", 2 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { "Bob", "male", 3 })));
+    }
+}
@@ -0,0 +1,24 @@
+package com.ossez.localization;
+
+import java.text.MessageFormat;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
+import java.util.ResourceBundle;
+
+public class JavaSEFormat {
+
+    public static String getLabel(Locale locale, Object[] data) {
+        ResourceBundle bundle = ResourceBundle.getBundle("formats", locale);
+        final String pattern = bundle.getString("label");
+        final MessageFormat formatter = new MessageFormat(pattern, locale);
+        return formatter.format(data);
+    }
+
+    public static void run(List<Locale> locales) {
+        System.out.println("Java formatter");
+        final Date date = new Date(System.currentTimeMillis());
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { date, "Alice", 0 })));
+        locales.forEach(locale -> System.out.println(getLabel(locale, new Object[] { date, "Alice", 2 })));
+    }
+}
@@ -0,0 +1,18 @@
+package com.ossez.localization;
+
+import java.util.List;
+import java.util.Locale;
+import java.util.ResourceBundle;
+
+public class Localization {
+
+    public static String getLabel(Locale locale) {
+        final ResourceBundle bundle = ResourceBundle.getBundle("messages", locale);
+        return bundle.getString("label");
+    }
+
+    public static void run(List<Locale> locales) {
+        locales.forEach(locale -> System.out.println(getLabel(locale)));
+    }
+
+}
@@ -0,0 +1,198 @@
+package com.ossez.stringperformance;
+
+import com.google.common.base.Splitter;
+import org.apache.commons.lang3.StringUtils;
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.StringTokenizer;
+import java.util.concurrent.TimeUnit;
+import java.util.regex.Pattern;
+
+@BenchmarkMode(Mode.SingleShotTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@Measurement(batchSize = 100000, iterations = 10)
+@Warmup(batchSize = 100000, iterations = 10)
+@State(Scope.Thread)
+public class StringPerformance {
+
+    protected String baeldung = "baeldung";
+    protected String longString = "Hello baeldung, I am a bit longer than other Strings";
+    protected String formatString = "hello %s, nice to meet you";
+    protected String formatDigit = "%d";
+    protected String emptyString = " ";
+    protected String result = "";
+
+    protected int sampleNumber = 100;
+
+    protected Pattern spacePattern = Pattern.compile(emptyString);
+    protected Pattern longPattern = Pattern.compile(longString);
+    protected List<String> stringSplit = new ArrayList<>();
+    protected List<String> stringTokenizer = new ArrayList<>();
+
+    @Benchmark
+    public String benchmarkStringDynamicConcat() {
+        result += baeldung;
+        return result;
+    }
+
+    @Benchmark
+    public StringBuilder  benchmarkStringBuilder() {
+        StringBuilder stringBuilder = new StringBuilder(result);
+        stringBuilder.append(baeldung);
+        return stringBuilder;
+    }
+
+    @Benchmark
+    public StringBuffer benchmarkStringBuffer() {
+        StringBuffer stringBuffer = new StringBuffer(result);
+        stringBuffer.append(baeldung);
+        return stringBuffer;
+    }
+
+    @Benchmark
+    public String benchmarkStringConstructor() {
+        String result = new String("baeldung");
+        return result;
+    }
+
+    @Benchmark
+    public String benchmarkStringLiteral() {
+        String result = "baeldung";
+        return result;
+    }
+
+    @Benchmark
+    public String benchmarkStringFormat_s() {
+        return String.format(formatString, baeldung);
+    }
+
+    @Benchmark
+    public String benchmarkStringConcat() {
+        result = result.concat(baeldung);
+        return result;
+    }
+
+    @Benchmark
+    public String benchmarkStringIntern() {
+        return baeldung.intern();
+    }
+
+    @Benchmark
+    public String benchmarkStringReplace() {
+        return longString.replace("average", " average !!!");
+    }
+
+    @Benchmark
+    public String benchmarkStringUtilsReplace() {
+        return StringUtils.replace(longString, "average", " average !!!");
+    }
+
+    @Benchmark
+    public List<String> benchmarkGuavaSplitter() {
+        return Splitter.on(" ").trimResults()
+                .omitEmptyStrings()
+                .splitToList(longString);
+    }
+
+    @Benchmark
+    public String [] benchmarkStringSplit() {
+        return longString.split(emptyString);
+    }
+
+    @Benchmark
+    public String [] benchmarkStringSplitPattern() {
+        return spacePattern.split(longString, 0);
+    }
+
+    @Benchmark
+    public List benchmarkStringTokenizer() {
+        StringTokenizer st = new StringTokenizer(longString);
+        while (st.hasMoreTokens()) {
+            stringTokenizer.add(st.nextToken());
+        }
+        return stringTokenizer;
+    }
+
+    @Benchmark
+    public List benchmarkStringIndexOf() {
+        int pos = 0, end;
+        while ((end = longString.indexOf(' ', pos)) >= 0) {
+            stringSplit.add(longString.substring(pos, end));
+            pos = end + 1;
+        }
+        //Add last token of string
+        stringSplit.add(longString.substring(pos));
+        return stringSplit;
+    }
+
+    @Benchmark
+    public String benchmarkIntegerToString() {
+        return Integer.toString(sampleNumber);
+    }
+
+    @Benchmark
+    public String benchmarkStringValueOf() {
+        return String.valueOf(sampleNumber);
+    }
+
+
+    @Benchmark
+    public String benchmarkStringConvertPlus() {
+        return sampleNumber + "";
+    }
+
+        @Benchmark
+    public String benchmarkStringFormat_d() {
+        return String.format(formatDigit, sampleNumber);
+    }
+
+    @Benchmark
+    public boolean benchmarkStringEquals() {
+        return longString.equals(baeldung);
+    }
+
+
+    @Benchmark
+    public boolean benchmarkStringEqualsIgnoreCase() {
+        return longString.equalsIgnoreCase(baeldung);
+    }
+
+    @Benchmark
+    public boolean benchmarkStringMatches() {
+        return longString.matches(baeldung);
+    }
+
+    @Benchmark
+    public boolean benchmarkPrecompiledMatches() {
+        return longPattern.matcher(baeldung).matches();
+    }
+
+    @Benchmark
+    public int benchmarkStringCompareTo() {
+        return longString.compareTo(baeldung);
+    }
+
+    @Benchmark
+    public boolean benchmarkStringIsEmpty() {
+        return longString.isEmpty();
+    }
+
+    @Benchmark
+    public boolean benchmarkStringLengthZero() {
+        return longString.length() == 0;
+    }
+
+    public static void main(String[] args) throws Exception {
+        Options options = new OptionsBuilder()
+                .include(StringPerformance.class.getSimpleName()).threads(1)
+                .forks(1).shouldFailOnError(true)
+                .shouldDoGC(true)
+                .jvmArgs("-server").build();
+        new Runner(options).run();
+    }
+}
@@ -0,0 +1,2 @@
+label=On {0, date, short} {1} has sent you {2, choice, 0#no messages|1#a message|2#two messages|2<{2,number,integer} messages}.
+label-icu={0} has sent you {2, plural, =0 {no messages} =1 {a message} other {{2, number, integer} messages}}.
@@ -0,0 +1,2 @@
+label={0, date, short}, {1}{2, choice, 0# ne|0<} vous a envoy\u00e9 {2, choice, 0#aucun message|1#un message|2#deux messages|2<{2,number,integer} messages}.
+label-icu={0} {2, plural, =0 {ne } other {}}vous a envoy\u00e9 {2, plural, =0 {aucun message} =1 {un message} other {{2, number, integer} messages}}.
@@ -0,0 +1,2 @@
+label={0, date, short} {1} ti ha inviato {2, choice, 0#nessun messagio|1#un messaggio|2#due messaggi|2<{2, number, integer} messaggi}.
+label-icu={0} {2, plural, =0 {non } other {}}ti ha inviato {2, plural, =0 {nessun messaggio} =1 {un messaggio} other {{2, number, integer} messaggi}}.
@@ -0,0 +1,2 @@
+label=W {0, date, short} {1}{2, choice, 0# nie|0<} wys\u0142a\u0142a ci {2, choice, 0#\u017Cadnych wiadomo\u015Bci|1#wiadomo\u015B\u0107|2#dwie wiadomo\u015Bci|2<{2, number, integer} wiadomo\u015Bci}.
+label-icu={0} {2, plural, =0 {nie } other {}}{1, select, male {wys\u0142a\u0142} female {wys\u0142a\u0142a} other {wys\u0142a\u0142o}} ci {2, plural, =0 {\u017Cadnej wiadomo\u015Bci} =1 {wiadomo\u015B\u0107} other {{2, number, integer} wiadomo\u015Bci}}.
@@ -0,0 +1 @@
+label=Alice has sent you a message.
@@ -0,0 +1 @@
+label=Alice vous a envoy\u00e9 un message.
@@ -0,0 +1 @@
+label=Alice ti ha inviato un messaggio.
@@ -0,0 +1 @@
+label=Alice wys\u0142a\u0142a ci wiadomo\u015B\u0107.
@@ -0,0 +1,4 @@
+Get busy living
+or
+get busy dying.
+--Stephen King
@@ -0,0 +1,20 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import java.math.BigDecimal;
+import java.text.NumberFormat;
+import java.util.Locale;
+
+import static org.junit.Assert.assertEquals;
+
+public class LocaleUnitTest {
+    @Test
+    public void whenUsingLocal_thenCorrectResultsForDifferentLocale() {
+        Locale usLocale = Locale.US;
+        BigDecimal number = new BigDecimal(102_300.456d);
+         
+        NumberFormat usNumberFormat = NumberFormat.getCurrencyInstance(usLocale); 
+        assertEquals(usNumberFormat.format(number), "$102,300.46");
+    }
+}
@@ -0,0 +1,29 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class StringAnagramUnitTest {
+    public boolean isAnagram(String s1, String s2) {
+        if(s1.length() != s2.length())
+            return false;
+            
+        char[] arr1 = s1.toCharArray();
+        char[] arr2 = s2.toCharArray();
+        
+        Arrays.sort(arr1);
+        Arrays.sort(arr2);
+        
+        return Arrays.equals(arr1, arr2);
+    }
+    
+    @Test
+    public void whenTestAnagrams_thenTestingCorrectly() {
+        assertThat(isAnagram("car", "arc")).isTrue();
+        assertThat(isAnagram("west", "stew")).isTrue();
+        assertThat(isAnagram("west", "east")).isFalse();
+    }
+}
@@ -0,0 +1,20 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class StringChangeCaseUnitTest {
+    @Test
+    public void givenString_whenChangingToUppercase_thenCaseChanged() {
+        String s = "Welcome to Baeldung!";
+        assertEquals("WELCOME TO BAELDUNG!", s.toUpperCase());
+    }
+    
+
+    @Test
+    public void givenString_whenChangingToLowerrcase_thenCaseChanged() {
+        String s = "Welcome to Baeldung!";
+        assertEquals("welcome to baeldung!", s.toLowerCase());
+    }
+}
@@ -0,0 +1,28 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class StringCountOccurrencesUnitTest {
+    public int countOccurrences(String s, char c) {
+        int count = 0;
+        for (int i = 0; i < s.length(); i++) {
+            if (s.charAt(i) == c) {
+                count++;
+            }
+        }
+        return count;
+    }
+
+    @Test
+    public void givenString_whenCountingFrequencyOfChar_thenCountCorrect() {
+        assertEquals(3, countOccurrences("united states", 't'));
+    }
+
+    public void givenString_whenUsingJava8_thenCountingOfCharCorrect() {
+        String str = "united states";
+        long count = str.chars().filter(ch -> (char)ch == 't').count();
+        assertEquals(3, count);
+    }
+}
@@ -0,0 +1,14 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class StringFormatUnitTest {
+    @Test
+    public void givenString_whenUsingStringFormat_thenStringFormatted() {
+        String title = "Baeldung"; 
+        String formatted = String.format("Title is %s", title);
+        assertEquals(formatted, "Title is Baeldung");
+    }
+}
@@ -0,0 +1,17 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class StringInternUnitTest {
+    @Test
+    public void whenCallingStringIntern_thenStringsInterned() {
+        String s1 = "Baeldung";
+        String s2 = new String("Baeldung");
+        String s3 = new String("Baeldung").intern();
+         
+        assertThat(s1 == s2).isFalse();
+        assertThat(s1 == s3).isTrue();
+    }
+}
@@ -0,0 +1,19 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import java.util.StringJoiner;
+
+import static org.junit.Assert.assertEquals;
+
+public class StringJoinerUnitTest {
+    @Test
+    public void whenUsingStringJoiner_thenStringsJoined() {
+        StringJoiner joiner = new StringJoiner(",", "[", "]");
+        joiner.add("Red")
+          .add("Green")
+          .add("Blue");
+         
+        assertEquals(joiner.toString(), "[Red,Green,Blue]");
+    }
+}
@@ -0,0 +1,29 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class StringPalindromeUnitTest {
+    
+    public boolean isPalindrome(String text) {
+        int forward = 0;
+        int backward = text.length() - 1;
+        while (backward > forward) {
+            char forwardChar = text.charAt(forward++);
+            char backwardChar = text.charAt(backward--);
+            if (forwardChar != backwardChar)
+                return false;
+        }
+        return true;
+    }
+    
+    @Test
+    public void givenIsPalindromeMethod_whenCheckingString_thenFindIfPalindrome() {
+        assertThat(isPalindrome("madam")).isTrue();
+        assertThat(isPalindrome("radar")).isTrue();
+        assertThat(isPalindrome("level")).isTrue();
+
+        assertThat(isPalindrome("baeldung")).isFalse();
+    }
+}
@@ -0,0 +1,13 @@
+package com.ossez.interview;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class StringReverseUnitTest {
+    @Test
+    public void whenUsingInbuildMethods_thenStringReversed() {
+        String reversed = new StringBuilder("baeldung").reverse().toString();
+        assertEquals("gnudleab", reversed);
+    }
+}
--- a/Show More
+++ b/Show More
				`@@ -0,0 +1 @@`
				`label=Alice wys\u0142a\u0142a ci wiadomo\u015B\u0107.`