Adding map() Stream Operation

spdpiyush · spdpiyush · commit d987cd840fd2 · 2025-02-26T13:16:44.000+05:30
diff --git a/Modern-Java-Examples/src/com/learn/streams/StreamsMapExample.java b/Modern-Java-Examples/src/com/learn/streams/StreamsMapExample.java
@@ -0,0 +1,44 @@
+package com.learn.streams;
+
+import com.learn.data.Student;
+import com.learn.data.StudentDataBase;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class StreamsMapExample {
+
+    public static void main(String[] args) {
+
+        System.out.println(namesList());
+
+        System.out.println(upperCaseNamesList());
+    }
+
+    /**
+     * <p>
+     *   we want all the names of Student from StudentDataBase and collect it in List.
+     * </p>
+     */
+    public static List<String> namesList() {
+        return StudentDataBase.getAllStudents().stream()
+                // this Map converting type, taking Student as i/p and return String as output.
+                .map(Student::getName)
+                .collect(Collectors.toList());
+    }
+
+    /**
+     * <p>
+     *     we want all the names of Student from StudentDataBase and collect it in List
+     *     and performing uppercase operation on that.
+     * </p>
+     * @return
+     */
+    public static List<String> upperCaseNamesList() {
+        return StudentDataBase.getAllStudents().stream()
+                .map(Student::getName)
+                // this Map not converting the type, taking String (name) as input and return String as output
+                .map(String::toUpperCase)
+                .collect(Collectors.toList());
+    }
+}
diff --git a/README.md b/README.md
@@ -24,6 +24,8 @@ This repository contains the basic &amp; advance level examples related to Java
   * [Streams](Modern-Java-Examples/src/com/learn/streams)
     * [Stream Example](Modern-Java-Examples/src/com/learn/streams/StreamsExample.java)
     * [Collection vs Stream](Modern-Java-Examples/src/com/learn/streams/CollectionVsStream.java)
+  * [Streams API Operations]
+    * [map()](Modern-Java-Examples/src/com/learn/streams/StreamsMapExample.java)
 
 
 
