Or-tools: Cannot build ortools from binary with jdk8

[unfuse]

I attempted to use OR-Tools installed from binary (for Java, on Mac) in a local project, and encountered an error in compilation. Error below:

bad class file: /Users/david.kennedy/Downloads/or-tools_MacOsX-10.14.2_v7.0.6546/lib/com.google.ortools.jar(com/google/ortools/graph/LinearSumAssignment.class)
class file has wrong version 54.0, should be 52.0
Please remove or make sure it appears in the correct subdirectory of the classpath.`

The instructions state you need jdk 7, and i have jdk 8, but it seems like the jar was built with jdk 10

cat MANIFEST.MF
Manifest-Version: 1.0
Created-By: 10.0.1 (Oracle Corporation)

[lperron]

We should be building using jdk8.
If not, it is a bug. We will check.

Thanks
Laurent Perron | Operations Research | [email protected] | (33) 1 42 68 53
00

Le ven. 12 avr. 2019 à 17:06, David Kennedy [e-mail] a
écrit :

I attempted to use OR-Tools installed from binary (for Java, on Mac) in a
local project, and encountered an error in compilation. Error below:

bad class file:
/Users/david.kennedy/Downloads/or-tools_MacOsX-10.14.2_v7.0.6546/lib/com.google.ortools.jar(com/google/ortools/graph/LinearSumAssignment.class)
class file has wrong version 54.0, should be 52.0
Please remove or make sure it appears in the correct subdirectory of the
classpath.`

The instructions
https://developers.google.com/optimization/install/java/mac state you
need jdk 7, and i have jdk 8, but it seems like the jar was built with jdk
10

cat MANIFEST.MF
Manifest-Version: 1.0
Created-By: 10.0.1 (Oracle Corporation)

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[Mizux]

When performing a brew update, I got Java 12 (which is the current default)

On my way to setup java8.

dev note:

# check java version available
brew tap caskroom/versions
brew search java

# Install JDK 8
brew cask install java8
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-8-latest/Contents/Home
java -version

# Makefile.local contains JAVa_HOME so need to suppress it by
make clean_third_party
# OR
rm Makefile.local
make detect_java

# Otherwise you can force it on cli since GNU/Make cli args have precedences over Makefile...
make detect_java JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-8-latest/Contents/Home

WARNING: /usr/libexec/java_home don't care about JAVA_HOME

[Mizux]

@unfuse I've just re-uploaded archive which should have been built against brew cask java8 package

[unfuse]

Thanks much! I noticed that the download link from the install site doesn't work anymore (https://github.com/google/or-tools/releases/download/v7.0/or-tools_MacOsX-10.14.2_v7.0.6546.tar.gz) - says not found. It looks like ...MacOsX-10.14.2... should be ...MacOsX-10.14.4...?

However, I tested by downloading it directly from https://github.com/google/or-tools/releases and built it with my local project and it works!

[Mizux]

Thanks for the feedback, I'll try to fix the link on documentation ASAP.

EDIT: optimization link have been updated !