examples/bin/verify-java

#!/usr/bin/env perl

# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

use strict;
use warnings;

my $java_version = qx[java -version 2>&1];
if ($?) {
  die "Please install Java 8 or better!\n";
}

# If we know it won't work, die. Otherwise hope for the best.
if ($java_version =~ /java version \"((\d+)\.(\d+).*?)\"/ && ($2 < 1 || $3 < 8)) {
  die "Please upgrade to Java 8 or better! Your current version is: $1\n";
}

exit 0;