It looks like I have the same issue. I use Android Studio 3.0 beta2.

objc[79443]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk/Contents/Home/bin/java (0x1079024c0) and /Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk/Contents/Home/jre/lib/libinstrument.dylib (0x1079ca4e0). One of the two will be used. Which one is undefined.
Exception in thread "main" java.lang.NoClassDefFoundError: org/greenrobot/greendao/generator/Schema
at co.fronto.daogenerator.Generator.main(Generator.java:11)
Caused by: java.lang.ClassNotFoundException: org.greenrobot.greendao.generator.Schema
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more

Process finished with exit code 1

I have the same issue. Please, could you give us some guidelines to repair it?

Solved!!
I update Android Studio to version 3.0.0 beta 5.
After I added in Android Studio config Build,Execution,Deployment/Compiler/Command.line Options this line: --debug --stacktrace
When I executed gradle/application/run I viewed in stacktrace one error: Not found mainClassName.
In Android Studio find Main class in DaoGenerator package, right button clicked/copy reference and paste in mainClassName in build.gradle.

After executed gradle/application/run and viewed other error in this line:
new DaoGenerator().generateAll(schema, "./app/src/main/java"); Path not exist.
Solved changing path like this:
new DaoGenerator().generateAll(schema, "../app/src/main/java");
When I executed last gradle/application/run, GreenDao generated new tables without error.

This is my DaoGenerator build.gradle:

apply plugin: 'java'
apply plugin: 'application'

mainClassName = "com.*****.daogenerator.DAoGenerator"
sourceCompatibility = 1.8

dependencies {
    compile fileTree(dir: 'libs',include: ['*.jar'])
    compile 'org.greenrobot:greendao-generator:3.2.2'
}

References:
https://github.com/greenrobot/greenDAO/blob/V2.2.1/DaoExampleGenerator/src/de/greenrobot/daogenerator/gentest/ExampleDaoGenerator.java
#619
http://greenrobot.org/greendao/documentation/updating-to-greendao-3-and-annotations/
https://stackoverflow.com/a/37356322/2183365

Changing from 2 dots to 1 dot worked for me. Thank you.

So the issue is just that paths are resolved differently? Closing this then. -ut