Update samples with the GCP telemetry endpoint (#398)

Author: psx95

examples/otlp-spring/README.md

@@ -24,7 +24,6 @@ Update [`build.gradle`](build.grade) to set the following:
 
 ```
 	'-Dgoogle.cloud.project=your-gcp-project-id',
-	'-Dotel.exporter.otlp.endpoint=https://your-api-endpoint:port',,
 ```
 
 ## Running Locally on your machine

examples/otlp-spring/build.gradle

@@ -44,7 +44,7 @@ dependencies {
 
 def autoconf_config = [
 	'-Dgoogle.cloud.project=your-gcp-project-id',
-	'-Dotel.exporter.otlp.endpoint=https://your-api-endpoint:port',
+	'-Dotel.exporter.otlp.endpoint=https://telemetry.googleapis.com',
 	'-Dotel.traces.exporter=otlp',
 	'-Dotel.metrics.exporter=none',
 	'-Dotel.exporter.otlp.protocol=http/protobuf',

examples/otlptrace/README.md

@@ -11,14 +11,10 @@ Executing this command will save your application credentials to default path wh
  - Linux, macOS: `$HOME/.config/gcloud/application_default_credentials.json`
  - Windows: `%APPDATA%\gcloud\application_default_credentials.json`
 
-Next, update the `build.gradle` file to modify required JVM arguments:
-
-```groovy
-def autoconf_config = [
-        '-Dgoogle.cloud.project=your-gcp-project-id',
-        '-Dotel.exporter.otlp.endpoint=https://your-api-endpoint:port',
-        // other arguments
-    ]
+Next, export the `GOOGLE_CLOUD_PROJECT` environment variable:
+```shell
+# Use your GCP project ID
+export GOOGLE_CLOUD_PROJECT="your-gcp-project-id"
 ```
 
 Finally, to run the sample from the project root:

examples/otlptrace/build.gradle

@@ -37,7 +37,7 @@ dependencies {
 // Provide headers from env variable
 def autoconf_config = [
 	'-Dgoogle.cloud.project=your-gcp-project-id',
-	'-Dotel.exporter.otlp.endpoint=https://your-api-endpoint:port',
+	'-Dotel.exporter.otlp.endpoint=https://telemetry.googleapis.com',
 	'-Dotel.traces.exporter=otlp',
 	'-Dotel.logs.exporter=none',
 	'-Dotel.metrics.exporter=none',