Improve the instructions to use Build me example

Signed-off-by: cmoulliard <[email protected]>

README.md

@@ -218,28 +218,31 @@ If the build fails for any reason, a `BuildpackException` will be thrown, this i
 
 To play with the Java Buildpack client & DSL, use the following simple java project: [samples/build-me](samples/build-me)
 
-To use it, just configure the following env var pointing to a project to be built as a container image
+To use it, configure the following mandatory environment variables pointing to a project (example: [hello-quarkus](samples/hello-quarkus), [hello-spring](samples/hello-spring)) to be built as a container image
 
 ```bash
 export PROJECT_PATH=<JAVA_PROJECT>
-export IMAGE_REF=<IMAGE_REF> // quay.io/<ORG>/<IMAGE_NAME> or <IMAGE_NAME>
+export IMAGE_REF=<IMAGE_REF> // <IMAGE_NAME> without registry or <REGISTRY_SERVER>/<REGISTRY_ORG>/<IMAGE_NAME>
 ```
-and execute this command in a terminal:
+
+**Important**: To avoid the `docker rate limit` problem, then set this `CNB_` environment variable to let `lifecycle` to get rid of the limit:
 ```bash
-mvn compile exec:java
+export CNB_REGISTRY_AUTH="'{"index.docker.io":"Basic <BASE64_OF_USERNAME:PASSWORD>"}'"
+
+// Replace `<BASE64_OF_USERNAME:PASSWORD> text with
+echo -n "username:password" | base64
 ```
-**Important**: To avoid the `docker rate limit` error, set the following env var:
+
+If you plan to push your image to a registry, then set your registry credential using these variables:
 ```bash
 export REGISTRY_USERNAME="<REGISTRY_USERNAME>"
 export REGISTRY_PASSWORD="<REGISTRY_PASSWORD>"
 export REGISTRY_SERVER="docker.io"
 ```
-and also set this one to let `lifecycle` to get rid of the docker limit: 
-```bash
-export CNB_REGISTRY_AUTH="'{"index.docker.io":"Basic <BASE64_OF_USERNAME:PASSWORD>"}'"
 
-// Replace `<BASE64_OF_USERNAME:PASSWORD> text with
-echo -n "username:password" | base64
+Execute this command in a terminal:
+```bash
+mvn compile exec:java
 ```
 
 ### Jbang

samples/build-me/README.md

@@ -3,27 +3,29 @@
 Example of a java project able to build a Quarkus, Spring Boot, ... project
 using the DSL `BuildConfig.builder()`
 
-To use it, just configure the following env var pointing to a project to be built as a container image
+To use it, configure the following mandatory environment variables pointing to a project (example: [hello-quarkus](../hello-quarkus), [hello-spring](../hello-spring)) to be built as a container image
 
 ```bash
 export PROJECT_PATH=<JAVA_PROJECT>
-export IMAGE_REF=<IMAGE_REF> // quay.io/<ORG>/<IMAGE_NAME> or <IMAGE_NAME>
+export IMAGE_REF=<IMAGE_REF> // <IMAGE_NAME> without registry or <REGISTRY_SERVER>/<REGISTRY_ORG>/<IMAGE_NAME>
 ```
-and execute this command in a terminal:
+
+**Important**: To avoid the `docker rate limit` problem, then set this `CNB_` environment variable to let `lifecycle` to get rid of the limit:
 ```bash
-mvn compile exec:java
+export CNB_REGISTRY_AUTH="'{"index.docker.io":"Basic <BASE64_OF_USERNAME:PASSWORD>"}'"
+
+// Replace `<BASE64_OF_USERNAME:PASSWORD> text with
+echo -n "username:password" | base64
 ```
 
-**Important**: To avoid the `docker rate limit` error, set the following env var:
+If you plan to push your image to a registry, then set your registry credential using these variables:
 ```bash
 export REGISTRY_USERNAME="<REGISTRY_USERNAME>"
 export REGISTRY_PASSWORD="<REGISTRY_PASSWORD>"
 export REGISTRY_SERVER="docker.io"
 ```
-and also set this one to let `lifecycle` to get rid of the docker limit:
-```bash
-export CNB_REGISTRY_AUTH="'{"index.docker.io":"Basic <BASE64_OF_USERNAME:PASSWORD>"}'"
 
-// Replace `<BASE64_OF_USERNAME:PASSWORD> text with
-echo -n "username:password" | base64
+Execute this command in a terminal:
+```bash
+mvn compile exec:java
 ```

samples/build-me/src/main/java/dev/snowdrop/BuildMe.java

@@ -23,7 +23,6 @@ public static void main(String... args) {
         String REGISTRY_PASSWORD = System.getenv("REGISTRY_PASSWORD");
         String REGISTRY_SERVER = System.getenv("REGISTRY_SERVER");
         String IMAGE_REF = System.getenv("IMAGE_REF");
-
         String PROJECT_PATH = System.getenv("PROJECT_PATH");
 
         Map<String, String> envMap = new HashMap<>();