Adding lamda, method reference and stream feature examples

Author: bhavnavarshney

Java/Java8/LambdaFeature.java

@@ -21,6 +21,7 @@ public void whatIsLamdaFeature() {
         MyInterface a ;
         // a = (String s) -> System.out.println("Hey! This is lamda function and much better way of implementing me! If you want to see the magic, checkout what is created after you compile me!");
         // As there is only 1 parameter - You can write like below without braces and type!
+        // This is implemented using Consumer interface!
         a = s-> System.out.println("Hey! This is lamda function and much better way of implementing me! If you want to see the magic, checkout what is created after you compile me, "+s);
 
         a.something("Developer");

Java/Java8/MethodRef.java

@@ -0,0 +1,34 @@
+package Java8;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+
+interface Parser {
+    String parse(String s);
+}
+
+class StringParser {
+    public static String convert(String s) {
+        if(s.length()<=3) {
+            s = s.toUpperCase();
+        }
+        return s;
+    }
+}
+class MyClass {
+    public void print(String s, Parser p) {
+        s = p.parse(s);
+        System.out.println(s);
+    }
+}
+public class MethodRef {
+    public void howIsMethodPassedAsRef() {
+        List<Integer> l = Arrays.asList(1,2,3,4);
+        l.forEach(System.out::println);
+
+        //Eg: 2
+        MyClass c = new MyClass();
+        c.print("Bhavna", StringParser::convert);
+    }
+}

Java/Java8/NewFeatures.java

@@ -12,6 +12,12 @@ public static void main(String[] args) {
 
         LambdaFeature lf = new LambdaFeature();
         lf.whatIsLamdaFeature();
+
+        StreamsDemo sd = new StreamsDemo();
+        sd.whatIsStream();
+
+        MethodRef mr = new MethodRef();
+        mr.howIsMethodPassedAsRef();
     }
 
 }

Java/Java8/StreamsDemo.java

@@ -0,0 +1,20 @@
+package Java8;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class StreamsDemo {
+    void whatIsStream() {
+        // It is used for processing the data. Can be used on once!
+
+        List<Integer> l = new ArrayList<>();
+        for(int i=1; i<=100; i++) {
+            l.add(i);
+        }
+        System.out.println(l.stream().filter(i->{
+            if(i==2) return true;
+            return false;
+        }).findAny().orElse(0));
+    }
+}