org.codehaus.mojo:exec-maven-plugin:3.0.0:java are missing or invalid

[j143]

> mvn compile exec:java

[INFO] Scanning for projects...
[INFO]
[INFO] ---------------< page.janardhan.labs:spanner-with-java >----------------
[INFO] Building spanner-with-java 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ spanner-with-java ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 2 resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ spanner-with-java ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent!
[INFO] Compiling 4 source files to F:\Repo\cloud\query-spanner-with-java\spanner-with-java\target\classes
[INFO] 
[INFO] --- exec-maven-plugin:3.0.0:java (default-cli) @ spanner-with-java ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  11.927 s
[INFO] Finished at: 2021-06-19T21:53:27+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:3.0.0:java (default-cli) on project spanner-with-java: The parameters 'mainClass' for goal org.codehaus.mojo:exec-maven-plugin:3.0.0:java are missing or invalid -> [Help 1]

[j143]

[ERROR] Unknown lifecycle phase ".mainClass=labs.App". You must specify a valid lifecycle phase or a goal in the format 
<plugin-prefix>:<goal> or <plugin-group-id>:<plugin-artifact-id>[:<plugin-version>]:<goal>. Available lifecycle phases are: 
validate, initialize, generate-sources, process-sources, generate-resources, process-resources, compile, process-classes, 
generate-test-sources, process-test-sources, generate-test-resources, process-test-resources, test-compile, process-test-classes, 
test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install, deploy, pre-clean, 
clean, post-clean, pre-site, site, post-site, site-deploy. -> [Help 1]