Fixed error handling when Java version can't be determined (#118)

* Fixed error handling when Java version can't be determined

* Made build getJavaExecutableVersion more resilient to output variations

gradle/java.gradle

@@ -234,14 +234,19 @@ JavaVersion getJavaExecutableVersion(String path) {
       commandLine = [path, "-version"]
       errorOutput = stream
     }
-    def matcher = stream.toString() =~ /^(?:java|openjdk) version "([^"]+)"/
-    if (matcher) {
-      def version = JavaVersion.toVersion(matcher.group(1))
-      cache.put(path, version)
-      return version
-    } else {
-      throw new GradleScriptException("Cannot determine java version: ${stream.toString}")
+    def output = stream.toString()
+    for (def line : output.split('\n')) {
+      line = line.trim()
+      def matcher = line =~ /^(?:java|openjdk) version "([^"]+)"/
+      if (matcher) {
+        def version = JavaVersion.toVersion(matcher.group(1))
+        cache.put(path, version)
+        return version
+      }
     }
+
+    // Getting here means we didn't find a line matching the version pattern.
+    throw new GradleScriptException("Cannot determine java version. Executable: ${path}, output: ${output}", null)
   }
 }