doc: improve examples doc

docs/user-guide/examples.md

@@ -3,6 +3,16 @@ built with the spark image tool, as described in the
 [spark documentation](https://spark.apache.org/docs/latest/running-on-kubernetes.html#docker-images).
 
 ### Python
+
+In this example, we use a small PySpark application that takes a parameter `num_points` to calculate the value of Pi:
+```python
+--8<-- "examples/python/job.py"
+```
+and a Dockerfile to package the application with the spark image:
+```dockerfile
+--8<-- "examples/python/Dockerfile"
+```
+
 First, build the docker image and push it to a registry accessible by your cluster,
 or load it into your cluster's local registry if you're using minikube or kind:
 ```bash
@@ -16,17 +26,29 @@ kind load docker-image pyspark-job
 # and then push it to that registry
 docker push pyspark-job
 ```
-Then, submit the job:
-```bash
-python examples/python/submit.py
+Then, you can submit the job using the python client:
+```python
+--8<-- "examples/python/submit.py"
 ```
-Or via the bash script:
+or using the CLI:
 ```bash
-./examples/python/submit.sh
+--8<-- "examples/python/submit.sh"
 ```
 
 ### Java
-Same as above, but with the java example:
+This example is similar to the previous one, but it's implemented in java (with maven).
+
+pom.xml:
+```xml
+--8<-- "examples/java/job/pom.xml"
+```
+the job class (`src/main/java/com/oss_tech/examples/TestJob.java`):
+```java
+--8<-- "examples/java/job/src/main/java/com/oss_tech/examples/TestJob.java"
+```
+
+Similar to the PySpark application, you need to build the docker image and push it to a registry accessible by
+your cluster, or load it into your cluster's local registry if you're using minikube or kind:
 ```bash
 docker build -t java-spark-job examples/java
 
@@ -38,12 +60,11 @@ kind load docker-image java-spark-job
 # and then push it to that registry
 docker push java-spark-job
 ```
-Then, submit the job:
-```bash
-python examples/java/submit.py
+Then, submit the job using the python client:
+```python
+--8<-- "examples/java/submit.py"
 ```
-
-Or via the bash script:
+or using the CLI:
 ```bash
-./examples/java/submit.sh
-```
+--8<-- "examples/java/submit.sh"
+```