Merge 50968093- to master

[Completes #50968093]

Author: Glyn Normington

lib/java_buildpack/version_resolver.rb

@@ -102,6 +102,7 @@ def major_or_minor_and_tail(s)
         if s.nil? || s.empty?
           major_or_minor, tail = nil, nil
         else
+          raise "Invalid version '#{s}': must not end in '.'" if s[-1] == '.'
           tokens = s.match(/^([^\.]+)(?:\.(.*))?/)
 
           major_or_minor, tail = tokens[1..-1]
@@ -116,6 +117,7 @@ def micro_and_qualifier(s)
         if s.nil? || s.empty?
           micro, qualifier = nil, nil
         else
+          raise "Invalid version '#{s}': must not end in '_'" if s[-1] == '_'
           tokens = s.match(/^([^\_]+)(?:_(.*))?/)
 
           micro, qualifier = tokens[1..-1]

spec/java_buildpack/version_resolver_spec.rb

@@ -129,4 +129,10 @@
     expect { JavaBuildpack::VersionResolver.resolve('1.6.0_25', ['+']) }.to raise_error
   end
 
+  it 'should raise an exception when a version ends with a component separator' do
+    expect { JavaBuildpack::VersionResolver.resolve('1.', ['1.']) }.to raise_error
+    expect { JavaBuildpack::VersionResolver.resolve('1.7.', ['1.7.']) }.to raise_error
+    expect { JavaBuildpack::VersionResolver.resolve('1.7.0_', ['1.7.0_']) }.to raise_error
+  end
+
 end