-- Error message

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  5.619 s
[INFO] Finished at: 2020-03-07T19:53:43+09:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.5.1:compile (default-compile) on project Digital2U: Fatal error compiling: tools.jar not found: C:\Program Files\Java\jre1.8.0_161\..\lib\tools.jar -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

-- Solution

1) project clean
2) project_name > properties > Java Build Path > Source > ../src/test 선택 > Remove