Q:

H2o with predict_json: "Error: Could not find or load main class water.util.H2OPredictor"?

I tried to use the H2o predict_json in R, 
h2o.predict_json(modelpath, jsondata)

and got the error message:
Error: Could not find or load main class water.util.H2OPredictor

I am using h2o_3.20.0.8. 
I searched the documentation from H2o but didn't help.
> h2o.predict_json(modelpath, jsondata)
$error
[1] "Error: Could not find or load main class water.util.H2OPredictor"

Warning message:
In system2(java, args, stdout = TRUE, stderr = TRUE) :
  running command ''java'  -Xmx4g -cp .:/Library/Frameworks/R.framework/Versions/3.5/Resources/library/mylib/Models/h2o-genmodel.jar:/Library/Frameworks/R.framework/Versions/3.5/Resources/library/mylib/Models:genmodel.jar:/ water.util.H2OPredictor  /Library/Frameworks/R.framework/Versions/3.5/Resources/library/mylib/Models/mymodel.zip '[{"da1":252,"da2":22,"da3":62,"da4":63,"da5":84.83}]' 2>&1' had status 1

A:

It looks like you are missing your h2o-genmodel.jar file - this is what the error message Could not find or load main class water.util.H2OPredictor indicates. You may want to provide all the arguments to checkoff that you have everything:
h2o.predict_json(model, json, genmodelpath, labels, classpath, javaoptions)
documentation here

