Error with H2O in R - can't connect to local host

Question

I can't get the h2o to work in my R. It shows the following error. Have no clue what it means. Previously it gave me an error because I didn't have Java 64 bit version. I downloaded the 64bit - restarted my pc - and started the process again and now it gives me this error.

Any suggestions?

library(h2o)

----------------------------------------------------------------------

Your next step is to start H2O:
    > h2o.init()

For H2O package documentation, ask for help:
    > ??h2o

After starting H2O, you can use the Web UI at http://localhost:54321
For more information visit http://docs.h2o.ai

----------------------------------------------------------------------


Attaching package: ‘h2o’

The following objects are masked from ‘package:stats’:

    cor, sd, var

The following objects are masked from ‘package:base’:

    %*%, %in%, &&, ||, apply, as.factor, as.numeric, colnames, colnames<-, ifelse,
    is.character, is.factor, is.numeric, log, log10, log1p, log2, round, signif, trunc

> h2o.init(nthreads = -1)

H2O is not running yet, starting it now...

Note:  In case of errors look at the following log files:
    C:\Users\ADM_MA~1\AppData\Local\Temp\RtmpygK1EJ/h2o_Adm_Mayur_started_from_r.out
    C:\Users\ADM_MA~1\AppData\Local\Temp\RtmpygK1EJ/h2o_Adm_Mayur_started_from_r.err

java version "9"
Java(TM) SE Runtime Environment (build 9+181)
Java HotSpot(TM) 64-Bit Server VM (build 9+181, mixed mode)

Starting H2O JVM and connecting: ............................................................ 
[1] "localhost"
[1] 54321
[1] TRUE
[1] -1
[1] "Failed to connect to localhost port 54321: Connection refused"
[1] 127
Error in h2o.init(nthreads = -1) : 
  H2O failed to start, stopping execution.
In addition: Warning message:
running command 'curl 'http://localhost:54321'' had status 127 

Screenshot for h2o error in R

Answer 1

Based on the error message and the troubleshooting we carried out in the comments, it seems that you are using a version of Java (Java 1.9) which is too new for your version of H2O.

Your 2 options seem to be:

1. Verify that your version of H2O is up to date. If not, update it.
2. Download a compatible version of Java, i.e. Java 1.8 (you can just use it for this 1 task rather than for everything, if you prefer)

Note that on the main documentation page of H2O v3 it says:

Java 7 or later. Note: Java 9 is not yet released and is not currently supported.

But at the same time they usually have several Beta and Alpha development branches going, so you might find one of those that works with Java 9.