Catch exceptions of IDToken construction

Author: emmyzhou-db

databricks-sdk-java/src/main/java/com/databricks/sdk/core/oauth/EnvVarIDTokenSource.java

@@ -41,10 +41,12 @@ public IDToken getIDToken(String audience) {
       throw new IllegalArgumentException("Environment cannot be null");
     }
 
-    String token = env.get(envVarName);
-    if (Strings.isNullOrEmpty(token)) {
-      throw new DatabricksException("Missing environment variable: " + envVarName);
+    try {
+      String token = env.get(envVarName);
+      return new IDToken(token);
+    } catch (IllegalArgumentException e) {
+      throw new DatabricksException(
+          "Received empty ID token from environment variable " + envVarName);
     }
-    return new IDToken(token);
   }
 }

databricks-sdk-java/src/main/java/com/databricks/sdk/core/oauth/FileIDTokenSource.java

@@ -56,12 +56,13 @@ public IDToken getIDToken(String audience) {
         throw new DatabricksException("File " + filePath + " is empty");
       }
 
-      String token = lines.get(0).trim();
-      if (Strings.isNullOrEmpty(token)) {
-        throw new DatabricksException("File " + filePath + " is empty");
+      try {
+        String token = lines.get(0).trim();
+        return new IDToken(token);
+      } catch (IllegalArgumentException e) {
+        throw new DatabricksException("Received empty ID token from file " + filePath);
       }
 
-      return new IDToken(token);
     } catch (IOException e) {
       throw new DatabricksException(
           "Failed to read ID token from file " + filePath + ": " + e.getMessage(), e);