Update java.md

Updated this page with steps to install the v3 client SDK and sample program so as to make developer's life bit easy.

content/influxdb/cloud-serverless/reference/client-libraries/v3/java.md

@@ -21,3 +21,73 @@ to write and query data stored in an {{% product-name %}} bucket.
 The documentation for this client library is available on GitHub.
 
 <a href="https://github.com/InfluxCommunity/influxdb3-java" target="_blank" class="btn github">InfluxDB v3 Java client library</a>
+
+## Installation
+
+### Maven
+```xml
+<dependency>
+  <groupId>com.influxdb</groupId>
+  <artifactId>influxdb3-java</artifactId>
+  <version>RELEASE</version>
+</dependency>
+```
+
+### Gradle
+```groovy
+implementation group: 'com.influxdb', name: 'influxdb3-java', version: 'latest.release'
+```
+
+## Sample Code
+
+```java
+public class HelloInfluxDB {
+  private static final String HOST_URL = "https://eu-central-1-1.aws.cloud2.influxdata.com"; // URL information is present in the cloud portal
+  private static final String DATABASE = "java"; // Database name is the bucket name present in the cloud portal
+  private static final char[] API_TOKEN = "API_TOKEN".toCharArray(); // Avoid hard-coding API_TOKEN in production. It is present in the cloud portal.
+
+  // Authenticate, Write and Query data from the serverless InfluxDB
+  public static void main(String[] args) {
+    try (InfluxDBClient client = InfluxDBClient.getInstance(HOST_URL, API_TOKEN, DATABASE)) {
+      writeData(client);
+      queryData(client);
+    }
+    catch (Exception e) {
+      System.err.println("An error occurred while connecting with the serverless InfluxDB!");
+      e.printStackTrace();
+    }
+  }
+
+  // Write sample measurement using Point class API
+  private static void writeData(InfluxDBClient client) {
+    Point point = Point.measurement("temperature")
+                       .setTag("location", "London")
+                       .setField("value", 30.01)
+                       .setTimestamp(Instant.now().minusSeconds(10));
+    try {
+      client.writePoint(point);
+      System.out.println("Data written to the bucket.");
+    }
+    catch (Exception e) {
+      System.err.println("Failed to write data to the bucket.");
+      e.printStackTrace();
+    }
+  }
+
+  // Query the latest 10 measurements using SQL
+  private static void queryData(InfluxDBClient client) {
+    System.out.printf("--------------------------------------------------------%n");
+    System.out.printf("| %-8s | %-8s | %-30s |%n", "location", "value", "time");
+    System.out.printf("--------------------------------------------------------%n");
+
+    String sql = "select time,location,value from temperature order by time desc limit 10";
+    try (Stream<Object[]> stream = client.query(sql)) {
+      stream.forEach(row -> System.out.printf("| %-8s | %-8s | %-30s |%n", row[1], row[2], row[0]));
+    }
+    catch (Exception e) {
+      System.err.println("Failed to query data from the bucket.");
+      e.printStackTrace();
+    }
+  }
+}
+```