Java 8 poc code

.idea/.gitignore

+# Default ignored files
+/shelf/
+/workspace.xml

.idea/compiler.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <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="com.main.poc" />
+      </profile>
+    </annotationProcessing>
+  </component>
+</project>
\ No newline at end of file

.idea/jarRepositories.xml

+<?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>
\ No newline at end of file

.idea/misc.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/com.main.poc/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
\ No newline at end of file

.idea/modules.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/pocjava8.iml" filepath="$PROJECT_DIR$/.idea/pocjava8.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file

.idea/pocjava8.iml

+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file

.idea/vcs.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file

com.main.poc/pom.xml

+<?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>org.example</groupId>
+    <artifactId>com.main.poc</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+
+</project>
\ No newline at end of file

com.main.poc/src/main/java/org/poc/ConsumerUsage.java

+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+public class ConsumerUsage {
+    public static void main(String args[]){
+
+
+            List<String> cities = new ArrayList<>();
+            cities.add("Delhi");
+            cities.add("Mumbai");
+            cities.add("Goa");
+            cities.add("Pune");
+
+            Consumer<String> printConsumer= city-> System.out.println(city);
+            cities.forEach(printConsumer);
+            cities.forEach(System.out::println);
+
+            // predicate
+            System.out.println("**** test predicate");
+            Predicate<String> filterCity = city -> city.equals("Mumbai");
+            cities.stream().filter(filterCity).forEach(System.out::println);
+            cities.stream().filter(c->c.equalsIgnoreCase("Pune")).forEach(System.out::println);
+
+            // function
+        System.out.println("**** test function");
+        Function<String, Character> getFirstCharFunction = city -> {
+            return city.charAt(0);
+        };
+        cities.stream().map(getFirstCharFunction)
+                .forEach(System.out::println);
+        //cities.stream().map(city->city.charAt(0)).forEach(System.out::println);
+        }
+
+}

com.main.poc/src/main/java/org/poc/DefaultInterfaceTest.java

+public class DefaultInterfaceTest {
+    public static void main(String args[]){
+        DefaultMethodSampleImpl impl = new DefaultMethodSampleImpl();
+        impl.testDefault("default method is called");
+
+    }
+}

com.main.poc/src/main/java/org/poc/DefaultMethodSample.java

+public interface DefaultMethodSample {
+    default void testDefault(String str){
+        System.out.println(str);
+    }
+}

com.main.poc/src/main/java/org/poc/DefaultMethodSampleImpl.java

+public class DefaultMethodSampleImpl implements DefaultMethodSample {
+}

com.main.poc/src/main/java/org/poc/Employee.java

+
+public class Employee {
+    private int id;
+    private String name;
+    private int age;
+    private long salary;
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public long getSalary() {
+        return salary;
+    }
+
+    public void setSalary(long salary) {
+        this.salary = salary;
+    }
+
+
+    public Employee(int id, String name, int age, long salary) {
+        super();
+        this.id = id;
+        this.name = name;
+        this.age = age;
+        this.salary = salary;
+    }
+    @Override
+    public String toString() {
+        return "Employee [id=" + id + ", name=" + name + ", age=" + age + ", salary=" + salary + "]";
+    }
+}

com.main.poc/src/main/java/org/poc/ForEachSample.java

+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.function.Consumer;
+
+public class ForEachSample {
+    public static void main(String[] args) {
+        List<Integer> myList = Arrays.asList(1,244,343,33);
+        Iterator<Integer> it = myList.iterator();
+        while(it.hasNext()){
+            Integer i = it.next();
+            System.out.println("Iterator Value::"+i);
+        }
+        List<String> bankNameList = Arrays.asList("hdfc","icici","boa");
+
+        System.out.println("Bank  Name List");
+                bankNameList.forEach(bankName -> System.out.println(bankName));
+
+    }
+
+}
+
+
+

com.main.poc/src/main/java/org/poc/Main.java

+public class Main {
+    public static void main(String[] args) {
+        System.out.println("Hello world!");
+    }
+}
\ No newline at end of file

com.main.poc/src/main/java/org/poc/OccurrenceOfCharInString.java

+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class OccurrenceOfCharInString {
+    public static void main(String args[]){
+
+        String testCharCount = "OCcurrence ";
+    Map<String, Long> count = Arrays.stream(testCharCount.split(""))
+            //.map(String::toLowerCase)
+            .collect(Collectors.groupingBy(s->s, LinkedHashMap::new , Collectors.counting()));
+        System.out.println(count);
+        Map<String, Long> result = Arrays.stream(testCharCount.split("")).map(String::toLowerCase).
+                collect(Collectors.groupingBy(s -> s, LinkedHashMap::new, Collectors.counting()));
+        System.out.println(result);
+
+    }
+}

com.main.poc/src/main/java/org/poc/OccurrenceOfNumInArray.java

+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class OccurrenceOfNumInArray {
+    public static void main(String args[]){
+        //List<Integer> arr = Arrays.asList(12,12,12,4,4,4,4,3,3,3,2);
+        int[] arr = {10, 10, 22, 22, 22, 43, 21};
+        List<Integer> numsList=Arrays.asList(1,2,3,5,2,4,3,1,2,2,4,4,5);
+        List<Integer> test = Arrays.asList(22,33,3,1,1,1,1,2,3,33,33);
+        Map<Integer, Long> map=numsList.stream().collect(Collectors.groupingBy(Integer::intValue,Collectors.counting()));
+        System.out.println(map);
+        map.forEach((k,v)->{System.out.println(k+" = "+v);});
+        Map<Integer,Long> occurrences =
+                Arrays.stream(arr)
+                        .boxed()
+                        .collect(Collectors.groupingBy(s -> s, Collectors.counting()));
+        System.out.println(occurrences);
+    }
+}

com.main.poc/src/main/java/org/poc/OptionalClassSample.java

+import java.util.Optional;
+
+public class OptionalClassSample {
+
+        public static void main(String[] args) {
+            String[] str = new String[5];
+           // str[3] = "testPass";
+            Optional<String> checkNull =
+                    Optional.ofNullable(str[3]);
+            if (checkNull.isPresent()) {
+                String word = str[3].toLowerCase();
+                System.out.print(word);
+            } else
+                System.out.println("string is null");
+        }
+    }
+

com.main.poc/src/main/java/org/poc/TestSoryByKey.java

+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import static java.util.Map.Entry.comparingByValue;
+import static java.util.stream.Collectors.toMap;
+
+public class TestSoryByKey {
+    public static void main(String args[]){
+
+        HashMap<String, Integer> map = new HashMap();
+        map.put("java",233);
+        map.put("spring",233);
+        map.put("springboot",231);
+        map.put("UI",123);
+
+        HashMap<String,Integer> sortedMap = map.entrySet().stream().
+                sorted((i1,i2)
+                         ->i1.getKey().compareTo(i2.getKey())).
+                collect(toMap(Map.Entry::getKey,
+                         Map.Entry::getValue,
+                          (e1, e2) -> e1, LinkedHashMap::new));
+
+        System.out.println("Sorted Map:"+sortedMap);
+
+        HashMap<String, Integer> map2 = new HashMap();
+        map2.put("java",23);
+        map2.put("spring",233);
+        map2.put("springboot",231);
+        Map<String, Integer> sorted = map2
+                .entrySet()
+                .stream()
+                .sorted(comparingByValue())
+                .collect(toMap(Map.Entry::getKey,
+                         Map.Entry::getValue,
+                         (e1, e2) -> e1, LinkedHashMap::new));
+        System.out.println("Sort by Value: "+sorted);
+
+        Map<String,Integer> reverseOrder = map2
+                .entrySet()
+                .stream()
+                .sorted(Collections.reverseOrder(Map.Entry.comparingByValue()))
+                .collect(toMap(Map.Entry::getKey,
+                        Map.Entry::getValue,
+                        (e1, e2) -> e1, LinkedHashMap::new));
+        System.out.println("Sort by value in reverse Order: "+reverseOrder);
+
+        System.out.println(sortedMap);
+
+    }
+}