initial commit

new-features-in-java-interface/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

new-features-in-java-interface/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>new-features-in-java-interface</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

new-features-in-java-interface/.settings/org.eclipse.core.resources.prefs

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+eclipse.preferences.version=1
+encoding/<project>=UTF-8

new-features-in-java-interface/.settings/org.eclipse.jdt.core.prefs

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+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=17
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=17
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
+org.eclipse.jdt.core.compiler.release=enabled
+org.eclipse.jdt.core.compiler.source=17

new-features-in-java-interface/src/com/example/StudyInterfaceJava8.java

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+package com.example;
+
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class StudyInterfaceJava8 {
+
+	public static void main(String[] args) {
+		var numbers = List.of(4,8,15,16,23,42);
+		numbers.stream()
+		       .filter( J::isEven )
+		       .mapToInt( number -> number * number * number)
+		       .sum();
+
+	}
+
+}
+
+interface I { // before java 8
+	public abstract void fun(); 
+	public abstract void gun(); 
+	public abstract void sun(); 
+}
+
+interface J { // after java 8+
+	public abstract void fun(); 
+	public abstract void gun(); 
+	public abstract void sun(); 
+	// 1. default method
+	default public void run() {
+
+	}; 
+	// 2. static method
+	// Functional Programming Utility Method
+	public static boolean isEven(int number) { 
+		return number%2 == 0; 
+	}
+}
+
+interface K {
+	default void fun() {
+		haveFun();
+	}
+	default void sun() {
+		haveFun();
+	}
+	private void haveFun() {} // since java 9 
+	public static void haveRun() {
+		haveGun();
+	}
+	public static void haveRun(int x) {
+		haveGun();
+	}
+	private static void haveGun() {} // since java 9
+}
+
+class J1 implements J {
+
+	@Override
+	public void fun() { }
+
+	@Override
+	public void gun() { }
+
+	@Override
+	public void sun() {	}
+
+}
+
+interface LotteryService {
+	List<Integer> draw(int max,int size);
+
+	default List<List<Integer>> draw(int max,int size,int column){
+		return IntStream.range(0, column)
+				        .mapToObj(i -> draw(max,size))
+				        .toList();
+	}
+}
+
+
+
+
+
+
+
+
+
+
+
+
+

study-arrays/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

study-arrays/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>study-arrays</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

study-arrays/.settings/org.eclipse.core.resources.prefs

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+eclipse.preferences.version=1
+encoding/<project>=UTF-8

study-arrays/.settings/org.eclipse.jdt.core.prefs

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+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=17
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=17
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
+org.eclipse.jdt.core.compiler.release=enabled
+org.eclipse.jdt.core.compiler.source=17

study-arrays/src/com/example/StudyArray.java

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+package com.example;
+
+import java.util.Arrays;
+
+@SuppressWarnings("unused")
+public class StudyArray {
+
+	public static void main(String[] args) {
+		int x = 42; // scalar
+		int[] numbers = { 4, 8, 15, 16, 23, 42 }; // Heap
+		System.out.println(numbers.length);
+		int[] dizi;
+		dizi = new int[6]; // Heap -> Zero
+		dizi[0] = 4;
+		dizi[1] = 8;
+		dizi[2] = 15;
+		dizi[3] = 16;
+		dizi[4] = 23;
+		dizi[5] = 42;
+		int[] array;
+		array = new int[] { 4, 8, 15, 16, 23, 42 }; // Heap -> Zero
+		// System.out.println(array[6]); ArrayIndexOutOfBoudsException
+		// How to print array content
+		System.out.println(numbers);
+		System.out.println(Arrays.toString(numbers));
+		// Loop #1
+		for (int i = 0; i < numbers.length; ++i)
+			System.out.println(numbers[i]);
+		// Loop #1 - var
+		for (var i = 0; i < numbers.length; ++i)
+			System.out.println(numbers[i]);
+		// Loop #2 : Java SE 5 - for-each
+		for (var number : numbers) // safe, sequential, read-only
+			System.out.println(++number);
+		var sum = 0;
+		for (var number : numbers) {
+			if (number%2 == 1) { // if it is odd
+				var squared = number * number;
+				sum += squared;
+			}	
+		}
+
+		// Loop #3 : Java SE 8 -> Functional Programming
+		sum = Arrays.stream(numbers) // Stream API + Filter/Map/Reduce -> ForkJoin Framework -> JobStealing Algorithm
+				    .parallel() 
+		            .filter(u -> u%2 == 1)
+		            .map(y -> y*y)
+		            .sequential()
+		            .sum(); // Functional Programming: lazy-loading, functions?
+		// C++20: Ranges -> C++23
+	}
+
+}

study-date-time-api/.classpath

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+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

study-date-time-api/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>study-date-time-api</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

study-date-time-api/.settings/org.eclipse.core.resources.prefs

@@ -0,0 +1,4 @@
+eclipse.preferences.version=1
+encoding//src/com/example/CreatingDateAndTime.java=UTF-8
+encoding//src/com/example/StudyInternationalization.java=UTF-8
+encoding/<project>=UTF-8

study-date-time-api/.settings/org.eclipse.jdt.core.prefs

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+eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=17
+org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
+org.eclipse.jdt.core.compiler.compliance=17
+org.eclipse.jdt.core.compiler.debug.lineNumber=generate
+org.eclipse.jdt.core.compiler.debug.localVariable=generate
+org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
+org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
+org.eclipse.jdt.core.compiler.release=enabled
+org.eclipse.jdt.core.compiler.source=17

study-date-time-api/src/com/example/CreatingDateAndTime.java

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+package com.example;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.FormatStyle;
+import java.util.Locale;
+
+public class CreatingDateAndTime {
+
+	@SuppressWarnings("unused")
+	public static void main(String[] args) {
+		var tr = new Locale("tr","TR");
+		LocalDate localDate;
+		LocalTime localTime;
+		LocalDateTime localDateTime;
+		ZonedDateTime now = ZonedDateTime.now();
+		System.out.println(LocalDate.now());
+		System.out.println(LocalTime.now());
+		System.out.println(LocalDateTime.now());
+		System.out.println(ZonedDateTime.now());
+		DateTimeFormatter dtf = 
+			DateTimeFormatter.ofLocalizedDateTime(FormatStyle.FULL)
+			                 .withLocale(Locale.CHINA);
+		System.out.println(dtf.format(now));
+	}
+
+}

study-date-time-api/src/com/example/CreatingSpecificDateAndTime.java

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+package com.example;
+
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.time.Month;
+
+public class CreatingSpecificDateAndTime {
+
+	@SuppressWarnings("unused")
+	public static void main(String[] args) {
+		var birthDate1 = LocalDate.of(1973, Month.JULY, 11);
+		var birthDate2 = LocalDate.of(1973, 7, 11);
+		var time1 = LocalTime.of(9, 5);
+		var time2 = LocalTime.of(9, 5, 30);
+		var time3 = LocalTime.of(9, 5, 30, 200);
+        LocalDate.of(2020, Month.FEBRUARY, 30);
+	}
+
+}

study-date-time-api/src/com/example/DateTimeOperations.java

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+package com.example;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+
+public class DateTimeOperations {
+
+	public static void main(String[] args) {
+		LocalDate date = LocalDate.of(2100, 2, 27);
+		System.out.println(date);
+		date = date.plusDays(2);
+		System.out.println(date);
+		LocalTime time = LocalTime.of(9, 5);
+		System.out.println(time);
+		time = time.minusMinutes(10);
+		System.out.println(time);
+		// fluent api -> method chaining
+		LocalDateTime ldt = LocalDateTime.of(date,time);
+		System.out.println(ldt);
+		ldt = ldt.minusDays(1).minusHours(10).minusSeconds(30);
+		System.out.println(ldt);
+	}
+
+}

study-date-time-api/src/com/example/StudyDuration.java

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+package com.example;
+
+import java.time.Duration;
+import java.time.LocalTime;
+
+public class StudyDuration {
+
+	public static void main(String[] args) {
+		var daily = Duration.ofDays(1);
+		var hourly = Duration.ofHours(1);	
+		LocalTime time = LocalTime.of(9, 5);
+		time = time.plus(daily).plus(hourly);
+	}
+
+}