JAVA EE: June 2017

Instance method reference of an existing object| Method reference in Java 8 | Java method reference

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Instance method reference of an existing object| Method reference in Java 8 | Java method reference

Mechanic.java

import java.util.function.Consumer;

class Car
{
    private String name;

    public Car(String name)
    {
        super();
        this.name = name;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

}

public class Mechanic
{
    public void fix(Car c)
    {
        System.out.println("Mechanic is fixing " + c.getName());
    }

    public void execute(Car car, Consumer<Car> c)
    {
        c.accept(car);
    }
}

LambdaDemo.java

import java.util.function.Consumer;

public class LambdaDemo
{
    public static void main(String[] args)
    {

        final Mechanic mechanic = new Mechanic();
        Car car = new Car("Honda Jazz");

        // Using an anonymous class
        mechanic.execute(car, new Consumer<Car>()
        {
            public void accept(Car c)
            {
                mechanic.fix(c);
            }
        });

        // Using a lambda expression
        mechanic.execute(car, c -> mechanic.fix(c));

        // Using a method reference
        mechanic.execute(car, mechanic::fix);
    }

}

Output

Mechanic is fixing Honda Jazz
Mechanic is fixing Honda Jazz
Mechanic is fixing Honda Jazz

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_Instance_method_ref_mechanic-app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_Instance_method_ref_mechanic-app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_Instance_method_ref_mechanic-app/?at=master

See also:

Thursday 15 June 2017

Static Method reference - Number more than 50| Method reference in Java 8 | Java method reference

Click here to watch in Youtube :
https://www.youtube.com/watch?v=wuHdFDUE2uA&list=UUhwKlOVR041tngjerWxVccw

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Static Method reference - Number more than 50| Method reference in Java 8 | Java method reference

Numbers.java

import java.util.ArrayList;
import java.util.List;
import java.util.function.BiPredicate;

class Numbers
{
    public static boolean isMoreThanFifty(int n1, int n2)
    {
        return (n1 + n2) > 50;
    }

    public static List<Integer> findNumbers(List<Integer> list,
                                        BiPredicate<Integer, Integer> p)
    {
        List<Integer> newList = new ArrayList<>();
        for (Integer i : list)
        {
            if (p.test(i, i + 10))
            {
                newList.add(i);
            }
        }
        return newList;
    }
}

LambdaDemo.java

import java.util.Arrays;
import java.util.List;
import java.util.function.BiPredicate;

public class LambdaDemo
{
    public static void main(String[] args)
    {

        List<Integer> list = Arrays.asList(12, 5, 45, 18, 33, 24, 40);

        // Using an anonymous class
        List<Integer> listOfNumbers = Numbers.findNumbers(list, new BiPredicate<Integer, Integer>()
        {
            public boolean test(Integer i1, Integer i2)
            {
                return Numbers.isMoreThanFifty(i1, i2);
            }
        });
        
        System.out.println("listOfNumbers using a anonymous class = "+listOfNumbers);
        
        // Using a lambda expression
        listOfNumbers =Numbers.findNumbers(list, (i1, i2) -> Numbers.isMoreThanFifty(i1, i2));
        System.out.println("listOfNumbers using a lambda expression = "+listOfNumbers);
        
        // Using a method reference
        listOfNumbers = Numbers.findNumbers(list, Numbers::isMoreThanFifty);
        System.out.println("listOfNumbers using a method reference = "+listOfNumbers);
    }

}

Output

listOfNumbers using a anonymous class = [45, 33, 24, 40]
listOfNumbers using a lambda expression = [45, 33, 24, 40]
listOfNumbers using a method reference = [45, 33, 24, 40]

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_static_method_ref_more50_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_static_method_ref_more50_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_static_method_ref_more50_app/?at=master

See also:

Static Method reference - Number less than 50| Method reference in Java 8 | Java method reference

Click here to watch in Youtube :
https://www.youtube.com/watch?v=kLl--x0N3Q8&list=UUhwKlOVR041tngjerWxVccw

Click the below Image to Enlarge

Static Method reference - Number less than 50| Method reference in Java 8 | Java method reference

Numbers.java

import java.util.ArrayList;
import java.util.List;
import java.util.function.Predicate;

class Numbers
{
    public static boolean isLessThanFifty(int number)
    {
        return number < 50;
    }

    public static List<Integer> findNumbers(List<Integer> list,
                                                Predicate<Integer> p)
    {
        List<Integer> newList = new ArrayList<>();
        for (Integer i : list)
        {
            /*
             * test the number is less than 50
             * then add to the newList.
             */
            if (p.test(i))
            {
                newList.add(i);
            }
        }
        return newList;
    }
}

LambdaDemo.java

import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

public class LambdaDemo
{
    public static void main(String[] args)
    {

        List<Integer> list = Arrays.asList(12, 55, 75, 88, 24, 40);

        // Using an anonymous class
        List<Integer> listOfLessthanfiftyNumbers = Numbers.findNumbers(list, new Predicate<Integer>()
        {
            public boolean test(Integer i)
            {
                return Numbers.isLessThanFifty(i);
            }
        });
        
        System.out.println("listOfLessthanfiftyNumbers - anonymous class = "+listOfLessthanfiftyNumbers);
        
        // Using a lambda expression
        listOfLessthanfiftyNumbers = Numbers.findNumbers(list, (i) -> Numbers.isLessThanFifty(i));
        System.out.println("listOfLessthanfiftyNumbers - lambda expression = "+listOfLessthanfiftyNumbers);
        
        // Using a method reference
        listOfLessthanfiftyNumbers = Numbers.findNumbers(list, Numbers::isLessThanFifty);
        System.out.println("listOfLessthanfiftyNumbers - method reference = "+listOfLessthanfiftyNumbers);
    }

}

Output

listOfLessthanfiftyNumbers - anonymous class = [12, 24, 40]
listOfLessthanfiftyNumbers - lambda expression = [12, 24, 40]
listOfLessthanfiftyNumbers - method reference = [12, 24, 40]

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_static_method_ref_less50_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_static_method_ref_less50_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_static_method_ref_less50_app/?at=master

See also:

How to use Method reference in forEach method of List | Method reference in Java 8

Click here to watch in Youtube :
https://www.youtube.com/watch?v=LQX1Cl3ECrA&list=UUhwKlOVR041tngjerWxVccw

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How to use Method reference in forEach method of List | Method reference in Java 8

MethodReferenceDemo.java

import java.util.ArrayList;
import java.util.List;

public class MethodReferenceDemo
{
    public static void main(String[] args)
    {

        List<String> nameList = new ArrayList<>();
        nameList.add("Peter");
        nameList.add("John");
        nameList.add("Juli");
        nameList.add("Stephan");

        nameList.forEach(name -> System.out.println(name));
        
        System.out.println("------------------------");
        
        // method reference
        nameList.forEach(System.out::println);
    }

}

Output

Peter
John
Juli
Stephan
------------------------
Peter
John
Juli
Stephan

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_list_foreach_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_list_foreach_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/769cad933ec9a28ea0eb78bc3917feeab1685676/BasicJava/LambdaDemo_method_ref_list_foreach_app/?at=master

See also:

How to refer a constructor using method reference | Method reference in Java 8

Click here to watch in Youtube :
https://www.youtube.com/watch?v=AEywwBHNllo&list=UUhwKlOVR041tngjerWxVccw

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How to refer a constructor using method reference | Method reference in Java 8

MethodReferenceDemo.java

/**
 *
 * We are using functional interface Messageable and referring constructor with
 * the help of functional interface.
 *
 */
@FunctionalInterface
interface Messageable
{
    Message getMessage(String msg);
}

class Message
{
    public Message(String msg)
    {
        System.out.print(msg);
    }
}

public class MethodReferenceDemo
{
    public static void main(String[] args)
    {
        Messageable messageable = Message::new;
        messageable.getMessage("Hello");
    }
}

Output

Hello

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_constructor_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_constructor_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_method_ref_constructor_app/?at=master

See also:

Non-Static Method reference - BiFunction | Method reference in Java 8 | Java method reference

Click here to watch in Youtube :
https://www.youtube.com/watch?v=zqTh-I6HZ4A&list=UUhwKlOVR041tngjerWxVccw

MethodReferenceDemo.java

import java.util.function.BiFunction;

/**
 *
 * We are using predefined functional interface BiFunction and
 * referring a non-static method add(int a, int b) to it's functional
 * method apply(Integer t,Integer u).
 *
 */

class Arithmetic
{
    public int add(int a, int b)
    {
        return a + b;
    }
}

public class MethodReferenceDemo
{
    public static void main(String[] args)
    {
        BiFunction<Integer, Integer, Integer> adder = new Arithmetic()::add;
        int result = adder.apply(200, 200);
        System.out.println(result);
    }
}

Output

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_nonstatic_Bifunction_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_nonstatic_Bifunction_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_method_ref_nonstatic_Bifunction_app/?at=master

See also:

Wednesday 14 June 2017

Non-Static Method reference - Runnable| Method reference in Java 8 | Java method reference

Click here to watch in Youtube :
https://www.youtube.com/watch?v=lm8Z0vZ7Zg4&list=UUhwKlOVR041tngjerWxVccw

MethodReferenceDemo.java

/**
 *
 * We are using predefined functional interface Runnable and referring
 * a non-static method ThreadStatus() to it's functional method run().
 *
 */

public class MethodReferenceDemo
{
    public void ThreadStatus()
    {
        System.out.println("Thread is running...");
    }

    public static void main(String[] args)
    {
        MethodReferenceDemo methodReferenceDemo = new MethodReferenceDemo();
        Runnable runnable = methodReferenceDemo::ThreadStatus;
        Thread thread = new Thread(runnable);
        thread.start();
    }
}

Output

Thread is running...

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_nonstatic_runnable_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_nonstatic_runnable_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_method_ref_nonstatic_runnable_app/?at=master

See also:

Non-Static Method reference - Dog | Method reference in Java 8 | Java method reference

Click here to watch in Youtube :
https://www.youtube.com/watch?v=-aDo8HDxWgQ&list=UUhwKlOVR041tngjerWxVccw

Click the below Image to Enlarge

Non-Static Method reference - Dog | Method reference in Java 8 | Java method reference

MethodReferenceDemo.java

/**
 *
 * We have defined a functional interface Dog and referring a
 * non-static method dogEating() to it's functional method eat().
 *
 */

@FunctionalInterface
interface Dog
{
    void eat();
}

public class MethodReferenceDemo
{
    public void dogEating()
    {
        System.out.println("Dog is eating chicken.");
    }

    public static void main(String[] args)
    {
        // Creating object
        MethodReferenceDemo methodReferenceDemo = new MethodReferenceDemo();
        
        // Referring non-static method using reference
        Dog dog = methodReferenceDemo::dogEating;
        
        // Calling interface method
        dog.eat();
    }
}

Output

Dog is eating chicken.

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_nonstatic_dog_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_nonstatic_dog_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_method_ref_nonstatic_dog_app/?at=master

See also:

Monday 12 June 2017

Static Method reference - BiFunction Overload methods | Method reference in Java 8

Click here to watch in Youtube :
https://www.youtube.com/watch?v=NVnYhSQoKHU&list=UUhwKlOVR041tngjerWxVccw

Click the below Image to Enlarge

Static Method reference - BiFunction Overload methods | Method reference in Java 8

MethodReferenceDemo.java

import java.util.function.BiFunction;

/**
 *
 * We can also override static methods by referring methods. In the
 * following example, we have defined and overloaded three add
 * methods.
 *
 */

class Arithmetic
{
    public static int add(int a, int b)
    {
        return a + b;
    }

    public static float add(int a, float b)
    {
        return a + b;
    }

    public static float add(float a, float b)
    {
        return a + b;
    }
}

public class MethodReferenceDemo
{
    public static void main(String[] args)
    {
        BiFunction<Integer, Integer, Integer> adder1 = Arithmetic::add;
        BiFunction<Integer, Float, Float> adder2 = Arithmetic::add;
        BiFunction<Float, Float, Float> adder3 = Arithmetic::add;

        int result1 = adder1.apply(10, 20);
        System.out.println(result1);
        
        float result2 = adder2.apply(10, 20.3f);
        System.out.println(result2);
        
        float result3 = adder3.apply(10.6f, 20.8f);     
        System.out.println(result3);
    }
}

Output

30
30.3
31.4

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_static_BiFunc_overload_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_static_BiFunc_overload_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_method_ref_static_BiFunc_overload_app/?at=master

See also:

Static Method reference - BiFunction | Method reference in Java 8 | Java method reference

Click here to watch in Youtube :
https://www.youtube.com/watch?v=k7wG-XFyFWo&list=UUhwKlOVR041tngjerWxVccw

MethodReferenceDemo.java

import java.util.function.BiFunction;

/**
 *
 * We are using predefined functional interface BiFunction and
 * referring a static method add(int a, int b) to it's functional
 * method apply(Integer t,Integer u).
 *
 */

class Arithmetic
{
    public static int add(int a, int b)
    {
        return a + b;
    }
}

public class MethodReferenceDemo
{
    public static void main(String[] args)
    {
        BiFunction<Integer, Integer, Integer> adder = Arithmetic::add;
        int result = adder.apply(20, 20);
        System.out.println(result);
    }
}

Output

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_static_BiFunc_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_static_BiFunc_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_method_ref_static_BiFunc_app/?at=master

See also:

Static Method reference - Runnable| Method reference in Java 8 | Java method reference

Click here to watch in Youtube :
https://www.youtube.com/watch?v=bzTQ1eCgaBI&list=UUhwKlOVR041tngjerWxVccw

MethodReferenceDemo.java

/**
 *
 * We are using predefined functional interface Runnable and referring
 * a static method ThreadStatus() to it's functional method run().
 *
 */

public class MethodReferenceDemo
{
    public static void ThreadStatus()
    {
        System.out.println("Thread is running...");
    }

    public static void main(String[] args)
    {
        Runnable runnable = MethodReferenceDemo::ThreadStatus;
        Thread thread = new Thread(runnable);
        thread.start();
    }
}

Output

Thread is running...

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/LambdaDemo_method_ref_static_Runnable_app.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/LambdaDemo_method_ref_static_Runnable_app

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/525432e9afa25ee5052810cb2318f64453ffeffa/BasicJava/LambdaDemo_method_ref_static_Runnable_app/?at=master

See also: