CLI - Bad error message when maven is not present #304
Description
With only the JDK installed, the init command fails with a confusing error message.
The message should indicate that maven is not installed.
helidon init --debug
error: C:\Program Files\AdoptOpenJDK\jdk-11.0.8.10-hotspot\bin\mvn.cmd
java.lang.IllegalStateException: C:\Program Files\AdoptOpenJDK\jdk-11.0.8.10-hotspot\bin\mvn.cmd
at io.helidon.build.util.MavenCommand.mavenExecutable(MavenCommand.java:129)
at io.helidon.build.util.MavenCommand.mavenHome(MavenCommand.java:143)
at io.helidon.build.util.MavenCommand.installedVersion(MavenCommand.java:156)
at io.helidon.build.util.MavenCommand.assertRequiredMavenVersion(MavenCommand.java:196)
at io.helidon.build.cli.impl.CommandRequirements.requireMinimumMavenVersion(CommandRequirements.java:89)
at io.helidon.build.cli.impl.InitCommand.assertPreconditions(InitCommand.java:136)
at io.helidon.build.cli.impl.BaseCommand.execute(BaseCommand.java:52)
at io.helidon.build.cli.harness.CommandRunner.doExecuteCommand(CommandRunner.java:86)
at java.util.Optional.ifPresentOrElse(Optional.java:201)
at io.helidon.build.cli.harness.CommandRunner.doExecuteCommandName(CommandRunner.java:60)
at java.util.Optional.ifPresentOrElse(Optional.java:201)
at io.helidon.build.cli.harness.CommandRunner.doExecute(CommandRunner.java:50)
at java.util.Optional.ifPresentOrElse(Optional.java:203)
at io.helidon.build.cli.harness.CommandRunner.execute(CommandRunner.java:43)
at io.helidon.build.cli.harness.CommandRunner.execute(CommandRunner.java:118)
at io.helidon.build.cli.harness.CommandRunner.execute(CommandRunner.java:132)
at io.helidon.build.cli.impl.Main.main(Main.java:36)