Solution to erroneous "please update your maxent program to version 3.3.3b or later" error when running maxent from dismo & ENMTools

I originally encountered this problem when trying to run maxent from ENMTools; but it turns out it was a combination of problem with the dismo package, and with my Mac machine having different versions of java installed (1.6 and 1.8).

I am pasting the solution that worked for me below, and to other relevant lists if I find them, since I didn't find a direct answer online.

Thanks - Nick

Solution to erroneous "please update your maxent program to version 3.3.3b or later" error when running maxent from dismo

Hi all,

I spent about 2 hours figuring this out on my Mac, so I might as well share it, as I didn't find anything else on specifically this problem online. 

SUMMARY: After installing rJava, dismo, and downloading/pasting the new maxent.jar file into the dismo install, I still got this error: "please update your maxent program to version 3.3.3b or later" 

RESOLUTION: The error was erroenous, it was actually due to a java mismatch error, in R/R.app on Mac OS X

I am posting my notes on this for google-ability, perhaps it will help others, or perhaps it will help myself when I forget all of this and get stuck with the same error on a mac laptop or something in 6 months!

I. SETUP

MacOSX El Capitan, Version 10.11.6

Use R from Terminal, and from R.app

II. PROBLEM:

I got set up to run maxent from R/dismo. Steps:

- installed rJava 

- installed dismo

- Downloaded the new maxent.jar (3.4.0, released December 2016 I think) from:

http://biodiversityinformatics.amnh.org/open_source/maxent/

- copied the jar file into the java directory of the dismo install:

/Library/Frameworks/R.framework/Versions/3.3/Resources/library/dismo/java/

But, when, when running the example code in ?maxent, I got:

Loading required namespace: rJava

Error in .getMeVersion() : 

  please update your maxent program to version 3.3.3b or later. This version is no longer supported. 

You can download it here: http://www.cs.princeton.edu/~schapire/maxent/'

Seeing as I had the newest version of maxent, this was confusing.

III. DIAGNOSIS

It turns out that this was the real problem.  Inside the maxent.R code is the following:

https://github.com/cran/dismo/blob/master/R/maxent.R

=============================

.getMeVersion <- function() {

jar <- paste(system.file(package="dismo"), "/java/maxent.jar", sep='')

if (!file.exists(jar)) {

stop('file missing:\n', jar, '.\nPlease download it here: http://www.cs.princeton.edu/~schapire/maxent/')

}

.rJava()

mxe <- rJava::.jnew("meversion") 

v <- try(rJava::.jcall(mxe, "S", "meversion") )

if (class(v) == 'try-error') {

stop('"dismo" needs a more recent version of Maxent (3.3.3b or later) \nPlease download it here: http://www.cs.princeton.edu/~schapire/maxent/

\n and put it in this folder:\n',

system.file("java", package="dismo"))

} else if (v == '3.3.3a') { 

stop("please update your maxent program to version 3.3.3b or later. This version is no longer supported. \nYou can download it here: http://www.cs.princeton.edu/~schapire/maxent/'")

}

return(v)

}

=============================

This bit of the code determines the version of maxent.jar being used:

mxe <- rJava::.jnew("meversion") 

v <- try(rJava::.jcall(mxe, "S", "meversion") )

...however, "rJava::.jcall" was giving an error due to a mismatch in java versions.  Mac OS X comes with Java 1.6 installed, but I had installed the newest java for various other applications (Beast2 etc.)

The messages were slightly different in Terminal R and R.app, but they were messages like this:

java.lang.UnsupportedClassVersionError: Unsupported major.minor version 52.0

java.lang.UnsupportedClassVersionError: density/Utils

These produce a "try-error" in "v", leading to this code mistakenly assuming that the problem is an old maxent.jar:

===============

mxe <- rJava::.jnew("meversion") 

v <- try(rJava::.jcall(mxe, "S", "meversion") )

if (class(v) == 'try-error') {

stop('"dismo" needs a more recent version of Maxent (3.3.3b or later) \nPlease download it here: http://www.cs.princeton.edu/~schapire/maxent/

\n and put it in this folder:\n',

system.file("java", package="dismo"))

===============

I was able to find my java installs, on my Mac, with:

cd /Library/Java/JavaVirtualMachines/

ls

I had:

1.6.0.jdk

jdk1.8.0_51.jdk

IV. SOLUTION(S)

Various hints were on this page:

http://stackoverflow.com/questions/26948777/how-can-i-make-rjava-use-the-newer-version-of-java-on-osx

...but I did *not* find that I had to use sudo to re-install anything.  For me, what worked was:

SOLUTION: R from Terminal

1. From the Terminal, run: "R CMD javareconf"

2. Enter R, reinstall rJava *from source*, e.g.:

install.packages('rJava',,'http://www.rforge.net/')

3. I also re-installed dismo from source, and then re-pasted maxent.jar into /Library/Frameworks/R.framework/Versions/3.3/Resources/library/dismo/java/

Then, everything worked:

library(rJava)

library(dismo)

maxent()

> This is MaxEnt version 3.4.0 

V. NEW PROBLEM

However, when I opened R.app and tried running maxent(), I now got a new error on library(rJava):

========================================

library(rJava)

Error : .onLoad failed in loadNamespace() for 'rJava', details:

  call: dyn.load(file, DLLpath = DLLpath, ...)

  error: unable to load shared object '/Library/Frameworks/R.framework/Versions/3.3/Resources/library/rJava/libs/rJava.so':

  dlopen(/Library/Frameworks/R.framework/Versions/3.3/Resources/library/rJava/libs/rJava.so, 6): Library not loaded: @rpath/libjvm.dylib

  Referenced from: /Library/Frameworks/R.framework/Versions/3.3/Resources/library/rJava/libs/rJava.so

  Reason: image not found

Error: package or namespace load failed for ‘rJava’

========================================

VI. NEW SOLUTION

The solution to this, in R.app, was:

========================================

dyn.load('/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/server/libjvm.dylib')

library(rJava)

maxent()

> This is MaxEnt version 3.4.0 

========================================

To make this "permanent", I added:

dyn.load('/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/server/libjvm.dylib')

...to my .Rprofile file, an invisible file (you might have to create it in a plain-text editor) in your mac user directory ("cd ~").

This works, but presumably will have to be changed if/when I update java.

VII. RECOMMENDATION

This bit of code in the dismo R package should probably be updated:

===============

mxe <- rJava::.jnew("meversion") 

v <- try(rJava::.jcall(mxe, "S", "meversion") )

if (class(v) == 'try-error') {

stop('"dismo" needs a more recent version of Maxent (3.3.3b or later) \nPlease download it here: http://www.cs.princeton.edu/~schapire/maxent/

\n and put it in this folder:\n',

system.file("java", package="dismo"))

===============

...to (1) distinguish between Java errors and old Maxent versions; and (2) the link http://www.cs.princeton.edu/~schapire/maxent/ should be updated to the new link, for the open-source maxent, online at the American Museum: http://biodiversityinformatics.amnh.org/open_source/maxent/

I am posting this to a couple of relevant lists, perhaps it will help others, or perhaps it will help myself when I forget all of this and get stuck with the same error on a mac laptop or something in 6 months.

Thanks,

Nick

Nick Matzke contact info

Usually in Australia:

================================

Nicholas J. Matzke

Professional introduction: http://www.nickmatzke.net

Active work website: http://phylo.wikidot.com/nicholas-j-matzke

Discovery Early Career Researcher Award (DECRA) Fellow

DECRA granted by ARC (Australian Research Council)

Division of Ecology and Evolution (E&E)

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Research School of Biology (RSB)

The Australian National University

Room 208, Building 116, Gould Wing

The Australian National University

ACT 2601 AUSTRALIA

Email: nickmatzke.ncse@gmail.com

nick.matzke@anu.edu.au

Skype: nicholas.matzke

Cell (preferred): +61 0410-726-191

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Emails: same

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